diff --git a/CLAUDE.md b/CLAUDE.md
index 8a798e9..22795c3 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -54,7 +54,9 @@ So to add a field: add the public property, map it in `getMapping()`, and regist
 
 **`Parameters` subclasses:** `Event` (the aggregate root — holds `User $userData`, `Custom $customData`, a list of `Pixel`, plus `metadata` for app-internal use that is never sent), `User` (customer matching data), `Custom` (event-specific data like value/currency/contents), `Content` (a single item in `Custom::$contents`). `Event` auto-generates `eventId` (random, for [deduplication](https://developers.facebook.com/docs/marketing-api/conversions-api/parameters/server-event#event-id)) and `eventTime` in its constructor. `Event` is intentionally **not** `final` so consumers can subclass it into domain-specific events; the other data objects are `final`.
 
-**`Client` (`src/Client/Client.php`)** — `sendEvent()` delegates to `sendPreparedEvent($event->prepare())`. `Event::prepare()` returns a `PreparedEvent` (`src/Event/PreparedEvent.php`): the `getPayload()` array plus the delivery information (event name and id, pixels, test event code), made of scalars/arrays/`Pixel` only so consumers can hash at capture time and queue it. The pixels are cloned so it is a snapshot, and `withoutAccessTokens()`/`withAccessTokens()` (immutable) keep the tokens out of the queue and restore them by pixel id before sending. `sendPreparedEvent()` first rejects pixels without an access token with a `ClientException`, before any request, so an event is never delivered to only some of its pixels (Meta's own error for a missing token does not mention the token). It then POSTs the payload (form-encoded) to `graph.facebook.com/v{ApiConfig::APIVersion}/{pixelId}/events` once per pixel (each pixel carries its own access token). Non-200 responses throw `ClientException` built from `ErrorResponse`. HTTP is fully PSR-based: PSR-18 client and PSR-17 factories are auto-discovered via `php-http/discovery` but can be injected with `setHttpClient()` / `setRequestFactory()` / etc. The client is `LoggerAware` and defaults to `NullLogger`.
+**`Client` (`src/Client/Client.php`)** — `sendEvent()` delegates to `sendPreparedEvent($event->prepare())`. `Event::prepare()` returns a `PreparedEvent` (`src/Event/PreparedEvent.php`): the `getPayload()` array plus the delivery information (event name and id, pixels, test event code), made of scalars/arrays/`Pixel` only so consumers can hash at capture time and queue it. The pixels are cloned so it is a snapshot, and `withoutAccessTokens()`/`withAccessTokens()` (immutable) keep the tokens out of the queue and restore them by pixel id before sending. `sendPreparedEvent()` first rejects pixels without an access token with an `InvalidArgumentException`, before any request, so an event is never delivered to only some of its pixels (Meta's own error for a missing token does not mention the token). It then POSTs the payload (form-encoded) to `graph.facebook.com/v{ApiConfig::APIVersion}/{pixelId}/events` once per pixel (each pixel carries its own access token). A failure of the HTTP client is wrapped in a `TransportException`, and a non-200 response throws a `ResponseException` carrying the status code, the raw body and, when the body is in Meta's error format, the parsed `ErrorResponse`. HTTP is fully PSR-based: PSR-18 client and PSR-17 factories are auto-discovered via `php-http/discovery` but can be injected with `setHttpClient()` / `setRequestFactory()` / etc. The client is `LoggerAware` and defaults to `NullLogger`.
+
+**Exceptions (`src/Exception/`)** — everything the SDK throws implements `ExceptionInterface`. There are three concrete classes, one per thing a caller can do: `InvalidArgumentException` (extends SPL's; the caller's fault, never retry: bad cookie values, invalid event data, pixels without an access token, an unencodable payload), `TransportException` (no response; retry) and `ResponseException` (non-200; decide from `statusCode`/`errorResponse`). To keep that promise, never throw SPL exceptions or use `Webmozart\Assert\Assert` directly in `src/`: use `Setono\MetaConversionsApi\Assert`, an internal subclass whose failures throw the SDK's `InvalidArgumentException`, and wrap third-party exceptions (the Facebook `Normalizer`, PSR-18, `\JsonException`). `FbqGenerator` is the one place that does not throw: its output goes straight into a page, so it logs and returns an empty string when the data cannot be encoded.
 
 **`FbqGenerator` (`src/Generator/FbqGenerator.php`)** — the client-side counterpart. Generates the `fbq('init', ...)` / `fbq('track', ...)` JavaScript snippets, using the browser-context payload and reusing the same `eventId` so server and browser events deduplicate. `Event::isCustom()` decides between `track` and `trackCustom`.
 
diff --git a/README.md b/README.md
index 9f5e9c7..4decaed 100644
--- a/README.md
+++ b/README.md
@@ -129,20 +129,42 @@ $event->testEventCode = 'TEST12345';
 
 ### Error handling
 
-`sendEvent()` and `sendPreparedEvent()` throw a `ClientException` if Meta returns a non-2xx response. The message
-contains Meta's error message, code, trace id and the raw response (including the user-facing explanation when Meta
-provides one). They also throw it, without making any request, if one of the pixels has no access token:
+Everything the SDK throws implements `Setono\MetaConversionsApi\Exception\ExceptionInterface`, so you can catch it all in
+one place. There are three concrete exceptions, one for each thing you can do about a failure:
+
+| Exception | Thrown when | What to do |
+|---|---|---|
+| `InvalidArgumentException` | The SDK is given something it cannot work with: a pixel without an access token, event data Meta does not accept, a payload that cannot be encoded, a cookie value in the wrong format. Always thrown before any request is made | Fix the input. Retrying will not help |
+| `TransportException` | The request never got a response, e.g. a network error or a timeout. The exception from your HTTP client is the previous exception | Retry |
+| `ResponseException` | Meta, or a proxy in between, answered with anything but a 200 | Decide from `$e->statusCode` and `$e->errorResponse` |
+
+`ResponseException::$errorResponse` is the error Meta reported, with its `message`, `code`, `subcode`, `type`, `traceId`,
+the `transient` flag and the user-facing texts. It is null when the body is not in Meta's error format, which typically
+means the response came from a proxy. The raw body is always available as `$e->body`.
 
 ```php
-use Setono\MetaConversionsApi\Exception\ClientException;
+use Setono\MetaConversionsApi\Exception\ExceptionInterface;
+use Setono\MetaConversionsApi\Exception\ResponseException;
+use Setono\MetaConversionsApi\Exception\TransportException;
 
 try {
     $client->sendEvent($event);
-} catch (ClientException $e) {
-    $logger->error('Could not send event to Meta', ['exception' => $e]);
+} catch (TransportException $e) {
+    // no response at all: try again later
+} catch (ResponseException $e) {
+    if ($e->statusCode >= 500 || true === $e->errorResponse?->transient) {
+        // try again later
+    }
+
+    $logger->error('Meta rejected the event', ['exception' => $e, 'trace_id' => $e->errorResponse?->traceId]);
+} catch (ExceptionInterface $e) {
+    $logger->error('Could not send the event to Meta', ['exception' => $e]);
 }
 ```
 
+`InvalidArgumentException` extends PHP's own `\InvalidArgumentException`, so a plain `catch (\InvalidArgumentException $e)`
+works too.
+
 ## Sending events later, e.g. through a queue
 
 `User` holds the raw email addresses, phone numbers and names until the payload is built, so an `Event` should not be
@@ -165,8 +187,8 @@ $client->sendPreparedEvent($preparedEvent->withAccessTokens([
 `withAccessTokens()` takes the tokens indexed by pixel id and leaves pixels that are not in the list as they are. Both
 return a new instance. If your queue is trusted with the access tokens, you can skip both calls.
 
-If a pixel still has no access token when you send, the client throws a `ClientException` that names the pixel, before
-any request is made. The event is therefore never delivered to only some of its pixels.
+If a pixel still has no access token when you send, the client throws an `InvalidArgumentException` that names the
+pixel, before any request is made. The event is therefore never delivered to only some of its pixels.
 
 ## Browser-side tracking with deduplication
 
@@ -191,7 +213,8 @@ echo $generator->generateTrack($event);
 ```
 
 Both methods wrap the output in a `<script>` tag by default; pass `false` as the last argument to get the raw
-JavaScript instead (e.g. to combine several calls into one tag).
+JavaScript instead (e.g. to combine several calls into one tag). Because their output goes straight into a page, they
+do not throw when the data cannot be encoded as JSON: they log an error and return an empty string.
 
 ## Custom events
 
@@ -217,6 +240,8 @@ $event->userData->fbc = Fbc::fromString($_COOKIE['_fbc']);
 $event->userData->fbp = Fbp::fromString($_COOKIE['_fbp']);
 ```
 
+`fromString()` throws an `InvalidArgumentException` if the value does not have the expected format.
+
 ## Using your own HTTP client
 
 By default the client auto-discovers a PSR-18 client and PSR-17 factories. To inject your own (e.g. a preconfigured
diff --git a/UPGRADE-2.0.md b/UPGRADE-2.0.md
index 8c8d1c6..c41fd9e 100644
--- a/UPGRADE-2.0.md
+++ b/UPGRADE-2.0.md
@@ -4,8 +4,7 @@ The requirements are unchanged: PHP 8.1+ and the same dependencies as 1.x.
 
 ## `ClientInterface` has a second method, `sendPreparedEvent()`
 
-This is the only backwards-compatibility break, and it only affects you if you implement `ClientInterface` yourself,
-for instance in a decorator or a test double. Add:
+This only affects you if you implement `ClientInterface` yourself, for instance in a decorator or a test double. Add:
 
 ```php
 use Setono\MetaConversionsApi\Event\PreparedEvent;
@@ -16,20 +15,50 @@ public function sendPreparedEvent(PreparedEvent $preparedEvent): void;
 It sends an event that was prepared earlier with `Event::prepare()`, i.e. with the payload already normalized and
 hashed. `Client` implements it, and a decorator can simply forward the call.
 
-## Behaviour change in `Client::sendEvent()`
+## `ClientException` is gone; everything the SDK throws implements `ExceptionInterface`
 
-`sendEvent()` now delegates to `sendPreparedEvent($event->prepare())`, so the payload is built before the client checks
-whether the event has any pixels. The request that is sent is byte for byte the same as in 1.x. There is one observable
-difference: an event without pixels whose data is invalid, an unknown `action_source` for instance, now throws when the
-payload is built. In 1.x the client logged the missing pixels and returned without ever building the payload.
+There are three concrete exceptions in `Setono\MetaConversionsApi\Exception`, one for each thing you can do about a
+failure. See "Error handling" in the README for how to use them.
+
+| In 1.x | In 2.0 |
+|---|---|
+| `ClientException`, when Meta answered with an error | `ResponseException`. The error is no longer only a message: `$e->statusCode`, `$e->body` and `$e->errorResponse` (code, subcode, type, trace id, the transient flag, user-facing texts) |
+| `ClientException`, when the error response could not be parsed | `ResponseException` with `$e->errorResponse` being null |
+| The PSR-18 `ClientExceptionInterface` of your HTTP client escaped from `sendEvent()` | `TransportException`, with the PSR-18 exception as the previous exception |
+| A `\JsonException` escaped from `sendEvent()` when the payload could not be encoded | `InvalidArgumentException` |
+| `\InvalidArgumentException` or `Webmozart\Assert\InvalidArgumentException` from `Fbc::fromString()`, `Fbp::fromString()`, the `with*()` methods and `getPayload()` | `Setono\MetaConversionsApi\Exception\InvalidArgumentException` |
+
+What to change:
+
+- Replace `catch (ClientException $e)` with `catch (ExceptionInterface $e)`, or with the specific classes. If you caught
+  the PSR-18 exception around `sendEvent()`, catch `TransportException` instead.
+- The SDK's `InvalidArgumentException` extends PHP's `\InvalidArgumentException`, so existing
+  `catch (\InvalidArgumentException $e)` blocks keep working. A `catch` of `Webmozart\Assert\InvalidArgumentException`
+  does not.
+- When event data is invalid, e.g. an unknown `action_source`, the message now names the field, and the exception from
+  `facebook/php-business-sdk` is the previous exception.
+- `ErrorResponse` is no longer `@internal`. Its properties are now readonly, and `ErrorResponse::fromJson()` throws
+  `InvalidArgumentException` instead of `ClientException`.
+
+## `FbqGenerator::generateTrack()` no longer throws a `\JsonException`
+
+When the custom data cannot be encoded as JSON, it now logs an error and returns an empty string, which is what
+`generateInit()` already did. The output of both goes straight into a page, where an exception would break the page.
 
 ## Pixels without an access token are rejected before any request is made
 
 In 1.x the client sent the request anyway, and Meta answered with an error that does not mention the access token
 ("Unsupported post request. Object with ID ... does not exist, cannot be loaded due to missing permissions ..."). In 2.0
-the client throws a `ClientException` naming the pixels instead. The exception class is the same as before, but with
-several pixels there is a difference: all pixels are checked first, so the pixels listed before the one without an
-access token no longer receive the event.
+the client throws an `InvalidArgumentException` naming the pixels instead. With several pixels there is one more
+difference: all pixels are checked first, so the pixels listed before the one without an access token no longer receive
+the event.
+
+## Behaviour change in `Client::sendEvent()`
+
+`sendEvent()` now delegates to `sendPreparedEvent($event->prepare())`, so the payload is built before the client checks
+whether the event has any pixels. The request that is sent is byte for byte the same as in 1.x. There is one observable
+difference: an event without pixels whose data is invalid, an unknown `action_source` for instance, now throws when the
+payload is built. In 1.x the client logged the missing pixels and returned without ever building the payload.
 
 ## New in 2.0
 
diff --git a/src/Assert.php b/src/Assert.php
new file mode 100644
index 0000000..4eca30f
--- /dev/null
+++ b/src/Assert.php
@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Setono\MetaConversionsApi;
+
+use Setono\MetaConversionsApi\Exception\InvalidArgumentException;
+
+/**
+ * Makes a failed assertion throw the SDK's own exception, so that everything the SDK throws
+ * implements \Setono\MetaConversionsApi\Exception\ExceptionInterface
+ *
+ * @internal
+ */
+final class Assert extends \Webmozart\Assert\Assert
+{
+    /**
+     * @param string $message
+     */
+    protected static function reportInvalidArgument($message): never
+    {
+        throw new InvalidArgumentException($message);
+    }
+}
diff --git a/src/Client/Client.php b/src/Client/Client.php
index faf1d6c..78f6f8c 100644
--- a/src/Client/Client.php
+++ b/src/Client/Client.php
@@ -7,6 +7,7 @@
 use FacebookAds\ApiConfig;
 use Http\Discovery\Psr17FactoryDiscovery;
 use Http\Discovery\Psr18ClientDiscovery;
+use Psr\Http\Client\ClientExceptionInterface;
 use Psr\Http\Client\ClientInterface as HttpClientInterface;
 use Psr\Http\Message\RequestFactoryInterface;
 use Psr\Http\Message\StreamFactoryInterface;
@@ -15,7 +16,9 @@
 use Psr\Log\NullLogger;
 use Setono\MetaConversionsApi\Event\Event;
 use Setono\MetaConversionsApi\Event\PreparedEvent;
-use Setono\MetaConversionsApi\Exception\ClientException;
+use Setono\MetaConversionsApi\Exception\InvalidArgumentException;
+use Setono\MetaConversionsApi\Exception\ResponseException;
+use Setono\MetaConversionsApi\Exception\TransportException;
 
 final class Client implements ClientInterface, LoggerAwareInterface
 {
@@ -55,13 +58,23 @@ public function sendPreparedEvent(PreparedEvent $preparedEvent): void
         }
 
         if ([] !== $pixelIdsWithoutAccessToken) {
-            throw ClientException::missingAccessToken($pixelIdsWithoutAccessToken);
+            throw new InvalidArgumentException(sprintf(
+                'The event was not sent to Meta/Facebook because these pixels have no access token: %s. If the access tokens were removed with PreparedEvent::withoutAccessTokens(), add them back with PreparedEvent::withAccessTokens() before sending',
+                implode(', ', $pixelIdsWithoutAccessToken),
+            ));
         }
 
         $httpClient = $this->getHttpClient();
         $requestFactory = $this->getRequestFactory();
 
-        $data = json_encode([$preparedEvent->payload], \JSON_THROW_ON_ERROR);
+        try {
+            $data = json_encode([$preparedEvent->payload], \JSON_THROW_ON_ERROR);
+        } catch (\JsonException $e) {
+            throw new InvalidArgumentException(sprintf(
+                'The event was not sent to Meta/Facebook because its payload cannot be encoded as JSON: %s',
+                $e->getMessage(),
+            ), previous: $e);
+        }
 
         foreach ($preparedEvent->pixels as $pixel) {
             $body = [
@@ -81,10 +94,22 @@ public function sendPreparedEvent(PreparedEvent $preparedEvent): void
             ->withHeader('Accept', 'application/json')
             ->withBody($this->getStreamFactory()->createStream(http_build_query($body)));
 
-            $response = $httpClient->sendRequest($request);
+            try {
+                $response = $httpClient->sendRequest($request);
+            } catch (ClientExceptionInterface $e) {
+                throw new TransportException($e);
+            }
 
             if ($response->getStatusCode() !== 200) {
-                throw ClientException::fromErrorResponse(ErrorResponse::fromJson((string) $response->getBody()));
+                $body = (string) $response->getBody();
+
+                try {
+                    $errorResponse = ErrorResponse::fromJson($body);
+                } catch (\InvalidArgumentException $e) {
+                    throw new ResponseException($response->getStatusCode(), $body, null, $e);
+                }
+
+                throw new ResponseException($response->getStatusCode(), $body, $errorResponse);
             }
         }
     }
diff --git a/src/Client/ClientInterface.php b/src/Client/ClientInterface.php
index 81de862..a9305b5 100644
--- a/src/Client/ClientInterface.php
+++ b/src/Client/ClientInterface.php
@@ -6,7 +6,7 @@
 
 use Setono\MetaConversionsApi\Event\Event;
 use Setono\MetaConversionsApi\Event\PreparedEvent;
-use Setono\MetaConversionsApi\Exception\ClientException;
+use Setono\MetaConversionsApi\Exception\ExceptionInterface;
 
 /**
  * Implement this interface in a client that is able to send the conversion api event to a Meta/Facebook endpoint
@@ -14,7 +14,7 @@
 interface ClientInterface
 {
     /**
-     * @throws ClientException if a pixel has no access token or the request failed in any way
+     * @throws ExceptionInterface if the event's data is invalid, a pixel has no access token, or the request failed in any way
      */
     public function sendEvent(Event $event): void;
 
@@ -22,7 +22,7 @@ public function sendEvent(Event $event): void;
      * Sends an event that was prepared earlier with Event::prepare(). Use this when the personal data is hashed
      * at capture time and the event is sent later, for instance through a queue
      *
-     * @throws ClientException if a pixel has no access token or the request failed in any way
+     * @throws ExceptionInterface if a pixel has no access token, the payload cannot be encoded, or the request failed in any way
      */
     public function sendPreparedEvent(PreparedEvent $preparedEvent): void;
 }
diff --git a/src/Client/ErrorResponse.php b/src/Client/ErrorResponse.php
index 186f424..ffa5ecb 100644
--- a/src/Client/ErrorResponse.php
+++ b/src/Client/ErrorResponse.php
@@ -4,8 +4,8 @@
 
 namespace Setono\MetaConversionsApi\Client;
 
-use Setono\MetaConversionsApi\Exception\ClientException;
-use Webmozart\Assert\Assert;
+use Setono\MetaConversionsApi\Assert;
+use Setono\MetaConversionsApi\Exception\InvalidArgumentException;
 
 /**
  * Represents the error envelope Meta/Facebook returns when a request fails.
@@ -21,49 +21,38 @@
  *
  * Those optional fields are captured when present.
  *
- * @internal
+ * @see \Setono\MetaConversionsApi\Exception\ResponseException::$errorResponse
  */
 final class ErrorResponse
 {
+    private const EXPECTED_FORMAT = '{"error":{"message":"string","type":"string","code":int,"fbtrace_id":"string"}}';
+
     /**
-     * This is the raw json response
+     * @param string $json the raw json response
+     * @param bool|null $transient true if Meta considers the error temporary, i.e. retrying may succeed. Null if Meta did not say
      */
-    public string $json;
-
-    public string $message;
-
-    public string $type;
-
-    public int $code;
-
-    public string $traceId;
-
-    public ?int $subcode = null;
-
-    public ?bool $transient = null;
-
-    public ?string $userTitle = null;
-
-    public ?string $userMessage = null;
-
-    private function __construct(string $json, string $message, string $type, int $code, string $traceId)
-    {
-        $this->json = $json;
-        $this->message = $message;
-        $this->type = $type;
-        $this->code = $code;
-        $this->traceId = $traceId;
+    private function __construct(
+        public readonly string $json,
+        public readonly string $message,
+        public readonly string $type,
+        public readonly int $code,
+        public readonly string $traceId,
+        public readonly ?int $subcode,
+        public readonly ?bool $transient,
+        public readonly ?string $userTitle,
+        public readonly ?string $userMessage,
+    ) {
     }
 
     /**
-     * @throws ClientException if the JSON / response is invalid
+     * @throws InvalidArgumentException if the JSON is invalid or is not in Meta's error format
      */
     public static function fromJson(string $json): self
     {
         try {
             $data = json_decode($json, true, 512, \JSON_THROW_ON_ERROR);
         } catch (\JsonException $e) {
-            throw ClientException::invalidJson($e, $json);
+            throw new InvalidArgumentException(sprintf('The response is not valid JSON (%s): %s', $e->getMessage(), $json), previous: $e);
         }
 
         try {
@@ -74,7 +63,7 @@ public static function fromJson(string $json): self
             Assert::isArray($error);
 
             if (!isset($error['message'], $error['type'], $error['code'], $error['fbtrace_id'])) {
-                throw ClientException::invalidResponseFormat($json);
+                throw new InvalidArgumentException('One of the required fields is missing');
             }
 
             ['message' => $message, 'type' => $type, 'code' => $code, 'fbtrace_id' => $traceId] = $error;
@@ -95,16 +84,10 @@ public static function fromJson(string $json): self
 
             $userMessage = $error['error_user_msg'] ?? null;
             Assert::nullOrString($userMessage);
-        } catch (\InvalidArgumentException $e) {
-            throw ClientException::invalidResponseFormat($json);
+        } catch (InvalidArgumentException $e) {
+            throw new InvalidArgumentException(sprintf('Expected a JSON response like %s, but got %s', self::EXPECTED_FORMAT, $json), previous: $e);
         }
 
-        $self = new self($json, $message, $type, $code, $traceId);
-        $self->subcode = $subcode;
-        $self->transient = $transient;
-        $self->userTitle = $userTitle;
-        $self->userMessage = $userMessage;
-
-        return $self;
+        return new self($json, $message, $type, $code, $traceId, $subcode, $transient, $userTitle, $userMessage);
     }
 }
diff --git a/src/Event/Parameters.php b/src/Event/Parameters.php
index 7bf1354..dddf770 100644
--- a/src/Event/Parameters.php
+++ b/src/Event/Parameters.php
@@ -6,7 +6,8 @@
 
 use FacebookAds\Object\ServerSide\Normalizer;
 use FacebookAds\Object\ServerSide\Util;
-use Webmozart\Assert\Assert;
+use Setono\MetaConversionsApi\Assert;
+use Setono\MetaConversionsApi\Exception\InvalidArgumentException;
 
 abstract class Parameters
 {
@@ -79,7 +80,11 @@ private static function normalize($data, ?string $field = null)
         if (is_string($data)) {
             Assert::notNull($field);
             if (in_array($field, static::getNormalizedFields(), true)) {
-                $data = Normalizer::normalize($field, $data);
+                try {
+                    $data = Normalizer::normalize($field, $data);
+                } catch (\InvalidArgumentException $e) {
+                    throw new InvalidArgumentException(sprintf('The value of the field "%s" is invalid: %s', $field, $e->getMessage()), previous: $e);
+                }
             }
 
             if (in_array($field, static::getHashedFields(), true)) {
diff --git a/src/Exception/ClientException.php b/src/Exception/ClientException.php
deleted file mode 100644
index d3cb697..0000000
--- a/src/Exception/ClientException.php
+++ /dev/null
@@ -1,67 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace Setono\MetaConversionsApi\Exception;
-
-use JsonException;
-use Setono\MetaConversionsApi\Client\ErrorResponse;
-
-class ClientException extends \RuntimeException
-{
-    public static function invalidJson(JsonException $jsonException, string $json): self
-    {
-        $message = sprintf(
-            'The response from Meta/Facebook was not valid JSON. Given input: %s. Error was: %s',
-            $json,
-            $jsonException->getMessage(),
-        );
-
-        return new self($message, 0, $jsonException);
-    }
-
-    public static function invalidResponseFormat(string $json): self
-    {
-        return new self(sprintf(
-            'Expected a JSON response like %s, but got %s',
-            '{"error":{"message":"string","type":"string","code":int,"fbtrace_id":"string"}}',
-            $json,
-        ));
-    }
-
-    /**
-     * @param non-empty-list<string> $pixelIds the ids of the pixels that have no access token
-     */
-    public static function missingAccessToken(array $pixelIds): self
-    {
-        return new self(sprintf(
-            'The event was not sent to Meta/Facebook because these pixels have no access token: %s. If the access tokens were removed with PreparedEvent::withoutAccessTokens(), add them back with PreparedEvent::withAccessTokens() before sending',
-            implode(', ', $pixelIds),
-        ));
-    }
-
-    public static function fromErrorResponse(ErrorResponse $errorResponse): self
-    {
-        $message = sprintf(
-            'An error occurred sending an event to Meta/Facebook: %s (code: %d',
-            $errorResponse->message,
-            $errorResponse->code,
-        );
-
-        if (null !== $errorResponse->subcode) {
-            $message .= sprintf(', subcode: %d', $errorResponse->subcode);
-        }
-
-        $message .= sprintf(', type: %s, trace id: %s)', $errorResponse->type, $errorResponse->traceId);
-
-        // The user_* fields, when present, hold a human readable explanation aimed at the end user
-        $userMessage = trim(sprintf('%s %s', $errorResponse->userTitle ?? '', $errorResponse->userMessage ?? ''));
-        if ('' !== $userMessage) {
-            $message .= sprintf("\n\n%s", $userMessage);
-        }
-
-        $message .= sprintf("\n\nRaw JSON response:\n\n%s", $errorResponse->json);
-
-        return new self($message);
-    }
-}
diff --git a/src/Exception/ExceptionInterface.php b/src/Exception/ExceptionInterface.php
new file mode 100644
index 0000000..453b8ca
--- /dev/null
+++ b/src/Exception/ExceptionInterface.php
@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Setono\MetaConversionsApi\Exception;
+
+/**
+ * Implemented by every exception this SDK throws, so that you can catch them all in one place
+ */
+interface ExceptionInterface extends \Throwable
+{
+}
diff --git a/src/Exception/InvalidArgumentException.php b/src/Exception/InvalidArgumentException.php
new file mode 100644
index 0000000..9826fcb
--- /dev/null
+++ b/src/Exception/InvalidArgumentException.php
@@ -0,0 +1,13 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Setono\MetaConversionsApi\Exception;
+
+/**
+ * Thrown when the SDK is given something it cannot work with: a cookie value in the wrong format, event data Meta
+ * does not accept, a pixel without an access token, and so on. The caller has to fix the input; retrying will not help
+ */
+final class InvalidArgumentException extends \InvalidArgumentException implements ExceptionInterface
+{
+}
diff --git a/src/Exception/ResponseException.php b/src/Exception/ResponseException.php
new file mode 100644
index 0000000..4caa9e2
--- /dev/null
+++ b/src/Exception/ResponseException.php
@@ -0,0 +1,60 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Setono\MetaConversionsApi\Exception;
+
+use Setono\MetaConversionsApi\Client\ErrorResponse;
+
+/**
+ * Thrown when Meta/Facebook, or something in between like a proxy, answers with anything but a 200.
+ * Whether retrying makes sense depends on the status code and on the error Meta reported
+ */
+final class ResponseException extends \RuntimeException implements ExceptionInterface
+{
+    /**
+     * @param string $body the raw response body
+     * @param ErrorResponse|null $errorResponse the error Meta reported, or null if the body is not in Meta's error format,
+     *                                          which typically means that the response came from a proxy or a gateway
+     */
+    public function __construct(
+        public readonly int $statusCode,
+        public readonly string $body,
+        public readonly ?ErrorResponse $errorResponse,
+        ?\Throwable $previous = null,
+    ) {
+        parent::__construct(self::message($statusCode, $body, $errorResponse), 0, $previous);
+    }
+
+    private static function message(int $statusCode, string $body, ?ErrorResponse $errorResponse): string
+    {
+        if (null === $errorResponse) {
+            return sprintf(
+                "Meta/Facebook responded with status code %d and a body that is not in the expected error format:\n\n%s",
+                $statusCode,
+                $body,
+            );
+        }
+
+        $message = sprintf(
+            'An error occurred sending an event to Meta/Facebook: %s (status code: %d, code: %d',
+            $errorResponse->message,
+            $statusCode,
+            $errorResponse->code,
+        );
+
+        if (null !== $errorResponse->subcode) {
+            $message .= sprintf(', subcode: %d', $errorResponse->subcode);
+        }
+
+        $message .= sprintf(', type: %s, trace id: %s)', $errorResponse->type, $errorResponse->traceId);
+
+        // The user_* fields, when present, hold a human readable explanation aimed at the end user
+        $userMessage = trim(sprintf('%s %s', $errorResponse->userTitle ?? '', $errorResponse->userMessage ?? ''));
+        if ('' !== $userMessage) {
+            $message .= sprintf("\n\n%s", $userMessage);
+        }
+
+        return $message . sprintf("\n\nRaw response:\n\n%s", $body);
+    }
+}
diff --git a/src/Exception/TransportException.php b/src/Exception/TransportException.php
new file mode 100644
index 0000000..ab36461
--- /dev/null
+++ b/src/Exception/TransportException.php
@@ -0,0 +1,19 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Setono\MetaConversionsApi\Exception;
+
+use Psr\Http\Client\ClientExceptionInterface;
+
+/**
+ * Thrown when the request never resulted in a response, e.g. because of a network error or a timeout.
+ * The exception from the HTTP client is the previous exception. Retrying usually makes sense
+ */
+final class TransportException extends \RuntimeException implements ExceptionInterface
+{
+    public function __construct(ClientExceptionInterface $previous)
+    {
+        parent::__construct(sprintf('The request to Meta/Facebook failed: %s', $previous->getMessage()), 0, $previous);
+    }
+}
diff --git a/src/Generator/FbqGenerator.php b/src/Generator/FbqGenerator.php
index d75312a..6a38651 100644
--- a/src/Generator/FbqGenerator.php
+++ b/src/Generator/FbqGenerator.php
@@ -57,11 +57,19 @@ public function generateInit(
 
     public function generateTrack(Event $event, bool $includeScriptTag = true): string
     {
+        try {
+            $json = json_encode($event->customData->getPayload(Parameters::PAYLOAD_CONTEXT_BROWSER), \JSON_THROW_ON_ERROR);
+        } catch (\JsonException $e) {
+            $this->logger->error($e->getMessage());
+
+            return '';
+        }
+
         $str = sprintf(
             "fbq('%s', '%s', %s, {eventID: '%s'});",
             $event->isCustom() ? 'trackCustom' : 'track',
             $event->eventName,
-            json_encode($event->customData->getPayload(Parameters::PAYLOAD_CONTEXT_BROWSER), \JSON_THROW_ON_ERROR),
+            $json,
             $event->eventId,
         );
 
diff --git a/src/ValueObject/Fb.php b/src/ValueObject/Fb.php
index f895c21..ab99bfe 100644
--- a/src/ValueObject/Fb.php
+++ b/src/ValueObject/Fb.php
@@ -4,7 +4,8 @@
 
 namespace Setono\MetaConversionsApi\ValueObject;
 
-use Webmozart\Assert\Assert;
+use Setono\MetaConversionsApi\Assert;
+use Setono\MetaConversionsApi\Exception\InvalidArgumentException;
 
 abstract class Fb
 {
@@ -43,7 +44,7 @@ public function __construct()
     }
 
     /**
-     * @throws \InvalidArgumentException if the $value is not the correct format
+     * @throws InvalidArgumentException if the $value is not the correct format
      */
     abstract public static function fromString(string $value): self;
 
diff --git a/src/ValueObject/Fbc.php b/src/ValueObject/Fbc.php
index 46872f5..7b5ad3b 100644
--- a/src/ValueObject/Fbc.php
+++ b/src/ValueObject/Fbc.php
@@ -4,6 +4,8 @@
 
 namespace Setono\MetaConversionsApi\ValueObject;
 
+use Setono\MetaConversionsApi\Exception\InvalidArgumentException;
+
 /**
  * See https://developers.facebook.com/docs/marketing-api/conversions-api/parameters/fbp-and-fbc#fbc
  */
@@ -30,7 +32,7 @@ public function __construct(string $clickId)
     public static function fromString(string $value): self
     {
         if (preg_match(self::REGEXP_FBC, $value, $matches) !== 1) {
-            throw new \InvalidArgumentException(sprintf(
+            throw new InvalidArgumentException(sprintf(
                 'The value "%s" didn\'t match the expected pattern for fbc: "%s"',
                 $value,
                 self::REGEXP_FBC,
diff --git a/src/ValueObject/Fbp.php b/src/ValueObject/Fbp.php
index abe856b..e5a1ede 100644
--- a/src/ValueObject/Fbp.php
+++ b/src/ValueObject/Fbp.php
@@ -4,6 +4,8 @@
 
 namespace Setono\MetaConversionsApi\ValueObject;
 
+use Setono\MetaConversionsApi\Exception\InvalidArgumentException;
+
 /**
  * See https://developers.facebook.com/docs/marketing-api/conversions-api/parameters/fbp-and-fbc
  */
@@ -24,7 +26,7 @@ public static function fromString(string $value): self
         // Must match something like this: fb.1.1656874832584.1088522659 or fb.1.1656874832584.1088522659.AQEAAQMB
         // NOTICE we match for 13 digits for the creation time. That number will be 14 digits in year 2286, so I guess it's safe to test for a specific number of digits ;)
         if (preg_match('/^fb\.([012])\.(\d{13})\.(\d+)(?:\.([A-Za-z0-9_-]{2,8}))?$/', $value, $matches) !== 1) {
-            throw new \InvalidArgumentException(sprintf('The value "%s" didn\'t match the expected pattern for fbp', $value));
+            throw new InvalidArgumentException(sprintf('The value "%s" didn\'t match the expected pattern for fbp', $value));
         }
 
         return (new self())
diff --git a/tests/Client/ClientTest.php b/tests/Client/ClientTest.php
index 5dd189f..57f54c0 100644
--- a/tests/Client/ClientTest.php
+++ b/tests/Client/ClientTest.php
@@ -9,6 +9,7 @@
 use Http\Discovery\Strategy\DiscoveryStrategy;
 use Nyholm\Psr7\Factory\Psr17Factory;
 use PHPUnit\Framework\TestCase;
+use Psr\Http\Client\ClientExceptionInterface;
 use Psr\Http\Client\ClientInterface as HttpClientInterface;
 use Psr\Http\Message\RequestFactoryInterface;
 use Psr\Http\Message\RequestInterface;
@@ -19,7 +20,10 @@
 use Psr\Http\Message\UriInterface;
 use Setono\MetaConversionsApi\Event\Event;
 use Setono\MetaConversionsApi\Event\PreparedEvent;
-use Setono\MetaConversionsApi\Exception\ClientException;
+use Setono\MetaConversionsApi\Exception\ExceptionInterface;
+use Setono\MetaConversionsApi\Exception\InvalidArgumentException;
+use Setono\MetaConversionsApi\Exception\ResponseException;
+use Setono\MetaConversionsApi\Exception\TransportException;
 use Setono\MetaConversionsApi\Pixel\Pixel;
 use Setono\MetaConversionsApi\TestLogger;
 
@@ -235,8 +239,8 @@ public function it_throws_when_a_pixel_has_no_access_token(): void
 
         try {
             $client->sendEvent($event);
-            self::fail('Expected a ClientException');
-        } catch (ClientException $e) {
+            self::fail('Expected an InvalidArgumentException');
+        } catch (InvalidArgumentException $e) {
             self::assertStringContainsString('these pixels have no access token: pixel_id.', $e->getMessage());
         }
 
@@ -263,8 +267,8 @@ public function it_sends_nothing_when_any_of_the_pixels_has_no_access_token(): v
         try {
             // pixel_2 and pixel_4 were not in the list, so they are still without an access token
             $client->sendPreparedEvent($preparedEvent->withoutAccessTokens()->withAccessTokens(['pixel_1' => 'token_1', 'pixel_3' => 'token_3']));
-            self::fail('Expected a ClientException');
-        } catch (ClientException $e) {
+            self::fail('Expected an InvalidArgumentException');
+        } catch (InvalidArgumentException $e) {
             self::assertStringContainsString('these pixels have no access token: pixel_2, pixel_4.', $e->getMessage());
         }
 
@@ -291,8 +295,8 @@ public function it_treats_an_empty_access_token_as_missing(): void
 
         try {
             $client->sendEvent($event);
-            self::fail('Expected a ClientException');
-        } catch (ClientException $e) {
+            self::fail('Expected an InvalidArgumentException');
+        } catch (InvalidArgumentException $e) {
             self::assertStringContainsString('pixel_id', $e->getMessage());
         }
 
@@ -320,16 +324,13 @@ public function it_does_not_send_prepared_event_when_it_has_no_pixels(): void
     /**
      * @test
      */
-    public function it_throws_an_exception_when_the_response_is_not_successful(): void
+    public function it_throws_a_response_exception_with_the_error_meta_reported(): void
     {
+        $json = '{"error":{"message":"Invalid parameter","type":"OAuthException","code":100,"error_subcode":2804050,"is_transient":false,"fbtrace_id":"trace123"}}';
         $responseFactory = new Psr17Factory();
 
         $httpClient = new TestHttpClient();
-        $httpClient->response = $responseFactory
-            ->createResponse(400)
-            ->withBody($responseFactory->createStream(
-                '{"error":{"message":"Invalid parameter","type":"OAuthException","code":100,"fbtrace_id":"trace123"}}',
-            ));
+        $httpClient->response = $responseFactory->createResponse(400)->withBody($responseFactory->createStream($json));
 
         $client = new Client();
         $client->setHttpClient($httpClient);
@@ -337,10 +338,127 @@ public function it_throws_an_exception_when_the_response_is_not_successful(): vo
         $event = new Event(Event::EVENT_PURCHASE);
         $event->pixels[] = new Pixel('pixel_id', 'access_token');
 
-        $this->expectException(ClientException::class);
-        $this->expectExceptionMessage('Invalid parameter');
+        try {
+            $client->sendEvent($event);
+            self::fail('Expected a ResponseException');
+        } catch (ExceptionInterface $e) {
+            self::assertInstanceOf(ResponseException::class, $e);
+            self::assertSame(400, $e->statusCode);
+            self::assertSame($json, $e->body);
+            self::assertNotNull($e->errorResponse);
+            self::assertSame('Invalid parameter', $e->errorResponse->message);
+            self::assertSame(100, $e->errorResponse->code);
+            self::assertSame(2804050, $e->errorResponse->subcode);
+            self::assertFalse($e->errorResponse->transient);
+            self::assertSame('trace123', $e->errorResponse->traceId);
+            self::assertNull($e->getPrevious());
+        }
+    }
 
-        $client->sendEvent($event);
+    /**
+     * @test
+     */
+    public function it_throws_a_response_exception_when_the_body_is_not_in_metas_error_format(): void
+    {
+        $html = '<html><body>502 Bad Gateway</body></html>';
+        $responseFactory = new Psr17Factory();
+
+        $httpClient = new TestHttpClient();
+        $httpClient->response = $responseFactory->createResponse(502)->withBody($responseFactory->createStream($html));
+
+        $client = new Client();
+        $client->setHttpClient($httpClient);
+
+        $event = new Event(Event::EVENT_PURCHASE);
+        $event->pixels[] = new Pixel('pixel_id', 'access_token');
+
+        try {
+            $client->sendEvent($event);
+            self::fail('Expected a ResponseException');
+        } catch (ResponseException $e) {
+            self::assertSame(502, $e->statusCode);
+            self::assertSame($html, $e->body);
+            self::assertNull($e->errorResponse);
+            self::assertInstanceOf(InvalidArgumentException::class, $e->getPrevious());
+        }
+    }
+
+    /**
+     * @test
+     */
+    public function it_stops_at_the_first_pixel_that_gets_an_unsuccessful_response(): void
+    {
+        $responseFactory = new Psr17Factory();
+
+        $httpClient = new TestHttpClient();
+        $httpClient->response = $responseFactory->createResponse(500);
+
+        $client = new Client();
+        $client->setHttpClient($httpClient);
+
+        $event = new Event(Event::EVENT_PURCHASE);
+        $event->pixels[] = new Pixel('pixel_1', 'token_1');
+        $event->pixels[] = new Pixel('pixel_2', 'token_2');
+
+        try {
+            $client->sendEvent($event);
+            self::fail('Expected a ResponseException');
+        } catch (ResponseException $e) {
+            self::assertSame(500, $e->statusCode);
+        }
+
+        self::assertCount(1, $httpClient->requests);
+    }
+
+    /**
+     * @test
+     */
+    public function it_wraps_a_failure_of_the_http_client_in_a_transport_exception(): void
+    {
+        $httpClientException = new TestClientException('Connection timed out');
+
+        $httpClient = new TestHttpClient();
+        $httpClient->exception = $httpClientException;
+
+        $client = new Client();
+        $client->setHttpClient($httpClient);
+
+        $event = new Event(Event::EVENT_PURCHASE);
+        $event->pixels[] = new Pixel('pixel_id', 'access_token');
+
+        try {
+            $client->sendEvent($event);
+            self::fail('Expected a TransportException');
+        } catch (ExceptionInterface $e) {
+            self::assertInstanceOf(TransportException::class, $e);
+            self::assertSame('The request to Meta/Facebook failed: Connection timed out', $e->getMessage());
+            self::assertSame($httpClientException, $e->getPrevious());
+        }
+    }
+
+    /**
+     * @test
+     */
+    public function it_throws_when_the_payload_cannot_be_encoded(): void
+    {
+        $httpClient = new TestHttpClient();
+
+        $client = new Client();
+        $client->setHttpClient($httpClient);
+
+        // malformed UTF-8 cannot be JSON encoded
+        $preparedEvent = new PreparedEvent(Event::EVENT_PURCHASE, 'event_id', ['custom' => "\xB1\x31"], [new Pixel('pixel_id', 'access_token')]);
+
+        try {
+            $client->sendPreparedEvent($preparedEvent);
+            self::fail('Expected an InvalidArgumentException');
+        } catch (ExceptionInterface $e) {
+            self::assertInstanceOf(InvalidArgumentException::class, $e);
+            self::assertStringContainsString('cannot be encoded as JSON', $e->getMessage());
+            self::assertInstanceOf(\JsonException::class, $e->getPrevious());
+        }
+
+        self::assertCount(0, $httpClient->requests);
     }
 
     /**
@@ -371,6 +489,8 @@ final class TestHttpClient implements HttpClientInterface
 
     public ?ResponseInterface $response = null;
 
+    public ?ClientExceptionInterface $exception = null;
+
     public function __construct()
     {
         $this->responseFactory = new Psr17Factory();
@@ -380,10 +500,18 @@ public function sendRequest(RequestInterface $request): ResponseInterface
     {
         $this->requests[] = $request;
 
+        if (null !== $this->exception) {
+            throw $this->exception;
+        }
+
         return $this->response ?? $this->responseFactory->createResponse();
     }
 }
 
+final class TestClientException extends \RuntimeException implements ClientExceptionInterface
+{
+}
+
 final class TestRequestFactory implements RequestFactoryInterface
 {
     public int $calls = 0;
diff --git a/tests/Client/ErrorResponseTest.php b/tests/Client/ErrorResponseTest.php
index 6dbd4d3..3ba63d4 100644
--- a/tests/Client/ErrorResponseTest.php
+++ b/tests/Client/ErrorResponseTest.php
@@ -5,7 +5,7 @@
 namespace Setono\MetaConversionsApi\Client;
 
 use PHPUnit\Framework\TestCase;
-use Setono\MetaConversionsApi\Exception\ClientException;
+use Setono\MetaConversionsApi\Exception\InvalidArgumentException;
 
 /**
  * @covers \Setono\MetaConversionsApi\Client\ErrorResponse
@@ -52,13 +52,23 @@ public function it_captures_the_optional_fields_when_present(): void
         self::assertSame('trace123', $errorResponse->traceId);
     }
 
+    /**
+     * @test
+     */
+    public function it_captures_a_transient_error(): void
+    {
+        $errorResponse = ErrorResponse::fromJson('{"error":{"message":"Service temporarily unavailable","type":"OAuthException","code":2,"is_transient":true,"fbtrace_id":"trace123"}}');
+
+        self::assertTrue($errorResponse->transient);
+    }
+
     /**
      * @test
      */
     public function it_throws_when_the_response_is_not_valid_json(): void
     {
-        $this->expectException(ClientException::class);
-        $this->expectExceptionMessage('The response from Meta/Facebook was not valid JSON');
+        $this->expectException(InvalidArgumentException::class);
+        $this->expectExceptionMessage('The response is not valid JSON');
 
         ErrorResponse::fromJson('this is not json');
     }
@@ -70,7 +80,7 @@ public function it_throws_when_the_response_is_not_valid_json(): void
      */
     public function it_throws_when_the_response_does_not_have_the_expected_format(string $json): void
     {
-        $this->expectException(ClientException::class);
+        $this->expectException(InvalidArgumentException::class);
         $this->expectExceptionMessage('Expected a JSON response like');
 
         ErrorResponse::fromJson($json);
diff --git a/tests/Event/ContentTest.php b/tests/Event/ContentTest.php
index e45a6a8..54a5b06 100644
--- a/tests/Event/ContentTest.php
+++ b/tests/Event/ContentTest.php
@@ -5,6 +5,7 @@
 namespace Setono\MetaConversionsApi\Event;
 
 use PHPUnit\Framework\TestCase;
+use Setono\MetaConversionsApi\Exception\InvalidArgumentException;
 
 /**
  * @covers \Setono\MetaConversionsApi\Event\Content
@@ -43,7 +44,7 @@ public function it_rejects_an_invalid_delivery_category(): void
     {
         $content = new Content('product_id', 1, 9.95, 'teleportation');
 
-        $this->expectException(\InvalidArgumentException::class);
+        $this->expectException(InvalidArgumentException::class);
 
         $content->getPayload();
     }
diff --git a/tests/Event/CustomTest.php b/tests/Event/CustomTest.php
index 90b09aa..a3c5496 100644
--- a/tests/Event/CustomTest.php
+++ b/tests/Event/CustomTest.php
@@ -5,6 +5,7 @@
 namespace Setono\MetaConversionsApi\Event;
 
 use PHPUnit\Framework\TestCase;
+use Setono\MetaConversionsApi\Exception\InvalidArgumentException;
 
 /**
  * @covers \Setono\MetaConversionsApi\Event\Custom
@@ -76,7 +77,7 @@ public function it_rejects_values_it_cannot_normalize(): void
         $custom = new Custom();
         $custom->customProperties['unsupported'] = new \stdClass();
 
-        $this->expectException(\InvalidArgumentException::class);
+        $this->expectException(InvalidArgumentException::class);
 
         $custom->getPayload();
     }
diff --git a/tests/Event/EventTest.php b/tests/Event/EventTest.php
index 32c09cb..33fc719 100644
--- a/tests/Event/EventTest.php
+++ b/tests/Event/EventTest.php
@@ -5,6 +5,7 @@
 namespace Setono\MetaConversionsApi\Event;
 
 use PHPUnit\Framework\TestCase;
+use Setono\MetaConversionsApi\Exception\InvalidArgumentException;
 use Setono\MetaConversionsApi\Pixel\Pixel;
 use Setono\MetaConversionsApi\ValueObject\Fbc;
 use Setono\MetaConversionsApi\ValueObject\Fbp;
@@ -219,7 +220,8 @@ public function it_rejects_an_invalid_action_source(): void
     {
         $event = new Event(Event::EVENT_PURCHASE, 'not_a_valid_action_source');
 
-        $this->expectException(\InvalidArgumentException::class);
+        $this->expectException(InvalidArgumentException::class);
+        $this->expectExceptionMessage('The value of the field "action_source" is invalid');
 
         $event->getPayload();
     }
diff --git a/tests/Exception/InvalidArgumentExceptionTest.php b/tests/Exception/InvalidArgumentExceptionTest.php
new file mode 100644
index 0000000..6f19402
--- /dev/null
+++ b/tests/Exception/InvalidArgumentExceptionTest.php
@@ -0,0 +1,50 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Setono\MetaConversionsApi\Exception;
+
+use PHPUnit\Framework\TestCase;
+use Setono\MetaConversionsApi\Assert;
+use Setono\MetaConversionsApi\ValueObject\Fbc;
+
+final class InvalidArgumentExceptionTest extends TestCase
+{
+    /**
+     * @test
+     *
+     * @dataProvider catchableAs
+     *
+     * @param class-string<\Throwable> $class
+     */
+    public function it_can_be_caught_as_an_sdk_exception_and_as_an_spl_invalid_argument_exception(string $class): void
+    {
+        try {
+            Fbc::fromString('not an fbc value');
+            self::fail('Expected an exception');
+        } catch (\Throwable $e) {
+            self::assertInstanceOf($class, $e);
+        }
+    }
+
+    /**
+     * @return \Generator<string, array{class-string<\Throwable>}>
+     */
+    public static function catchableAs(): \Generator
+    {
+        yield 'the SDK interface' => [ExceptionInterface::class];
+        yield 'the SDK class' => [InvalidArgumentException::class];
+        yield 'the SPL class' => [\InvalidArgumentException::class];
+    }
+
+    /**
+     * @test
+     */
+    public function it_is_thrown_by_a_failed_assertion(): void
+    {
+        $this->expectException(InvalidArgumentException::class);
+        $this->expectExceptionMessage('Expected a string. Got: integer');
+
+        Assert::string(123);
+    }
+}
diff --git a/tests/Exception/ClientExceptionTest.php b/tests/Exception/ResponseExceptionTest.php
similarity index 50%
rename from tests/Exception/ClientExceptionTest.php
rename to tests/Exception/ResponseExceptionTest.php
index 3f984c9..b7ef2b0 100644
--- a/tests/Exception/ClientExceptionTest.php
+++ b/tests/Exception/ResponseExceptionTest.php
@@ -7,65 +7,24 @@
 use PHPUnit\Framework\TestCase;
 use Setono\MetaConversionsApi\Client\ErrorResponse;
 
-/**
- * @covers \Setono\MetaConversionsApi\Exception\ClientException
- */
-final class ClientExceptionTest extends TestCase
+final class ResponseExceptionTest extends TestCase
 {
     /**
      * @test
      */
-    public function it_is_created_from_invalid_json(): void
-    {
-        $jsonException = new \JsonException('Syntax error', \JSON_ERROR_SYNTAX);
-
-        $exception = ClientException::invalidJson($jsonException, 'this is not json');
-
-        self::assertSame(
-            'The response from Meta/Facebook was not valid JSON. Given input: this is not json. Error was: Syntax error',
-            $exception->getMessage(),
-        );
-        self::assertSame(0, $exception->getCode());
-        self::assertSame($jsonException, $exception->getPrevious());
-    }
-
-    /**
-     * @test
-     */
-    public function it_is_created_from_an_invalid_response_format(): void
-    {
-        $exception = ClientException::invalidResponseFormat('{"foo":"bar"}');
-
-        self::assertSame(
-            'Expected a JSON response like {"error":{"message":"string","type":"string","code":int,"fbtrace_id":"string"}}, but got {"foo":"bar"}',
-            $exception->getMessage(),
-        );
-    }
-
-    /**
-     * @test
-     */
-    public function it_is_created_from_pixels_without_an_access_token(): void
-    {
-        $exception = ClientException::missingAccessToken(['pixel_1', 'pixel_2']);
-
-        self::assertSame(
-            'The event was not sent to Meta/Facebook because these pixels have no access token: pixel_1, pixel_2. If the access tokens were removed with PreparedEvent::withoutAccessTokens(), add them back with PreparedEvent::withAccessTokens() before sending',
-            $exception->getMessage(),
-        );
-    }
-
-    /**
-     * @test
-     */
-    public function it_is_created_from_an_error_response(): void
+    public function it_describes_the_error_meta_reported(): void
     {
         $json = '{"error":{"message":"Invalid parameter","type":"OAuthException","code":100,"fbtrace_id":"trace123"}}';
 
-        $exception = ClientException::fromErrorResponse(ErrorResponse::fromJson($json));
+        $exception = new ResponseException(400, $json, ErrorResponse::fromJson($json));
 
+        self::assertSame(400, $exception->statusCode);
+        self::assertSame($json, $exception->body);
+        self::assertNotNull($exception->errorResponse);
+        self::assertSame(0, $exception->getCode());
+        self::assertNull($exception->getPrevious());
         self::assertSame(
-            "An error occurred sending an event to Meta/Facebook: Invalid parameter (code: 100, type: OAuthException, trace id: trace123)\n\nRaw JSON response:\n\n" . $json,
+            "An error occurred sending an event to Meta/Facebook: Invalid parameter (status code: 400, code: 100, type: OAuthException, trace id: trace123)\n\nRaw response:\n\n" . $json,
             $exception->getMessage(),
         );
     }
@@ -77,10 +36,10 @@ public function it_includes_the_subcode_and_the_user_facing_message_when_present
     {
         $json = '{"error":{"message":"Invalid parameter","type":"OAuthException","code":100,"error_subcode":2804050,"is_transient":false,"error_user_title":"Customer information parameters","error_user_msg":"This event has insufficient customer information.","fbtrace_id":"trace123"}}';
 
-        $exception = ClientException::fromErrorResponse(ErrorResponse::fromJson($json));
+        $exception = new ResponseException(400, $json, ErrorResponse::fromJson($json));
 
         self::assertSame(
-            "An error occurred sending an event to Meta/Facebook: Invalid parameter (code: 100, subcode: 2804050, type: OAuthException, trace id: trace123)\n\nCustomer information parameters This event has insufficient customer information.\n\nRaw JSON response:\n\n" . $json,
+            "An error occurred sending an event to Meta/Facebook: Invalid parameter (status code: 400, code: 100, subcode: 2804050, type: OAuthException, trace id: trace123)\n\nCustomer information parameters This event has insufficient customer information.\n\nRaw response:\n\n" . $json,
             $exception->getMessage(),
         );
     }
@@ -92,10 +51,10 @@ public function it_includes_the_subcode_and_the_user_facing_message_when_present
      */
     public function it_includes_the_user_facing_message_when_only_the_title_or_the_message_is_present(string $json, string $expectedUserFacingMessage): void
     {
-        $exception = ClientException::fromErrorResponse(ErrorResponse::fromJson($json));
+        $exception = new ResponseException(400, $json, ErrorResponse::fromJson($json));
 
         self::assertSame(
-            "An error occurred sending an event to Meta/Facebook: Invalid parameter (code: 100, type: OAuthException, trace id: trace123)\n\n" . $expectedUserFacingMessage . "\n\nRaw JSON response:\n\n" . $json,
+            "An error occurred sending an event to Meta/Facebook: Invalid parameter (status code: 400, code: 100, type: OAuthException, trace id: trace123)\n\n" . $expectedUserFacingMessage . "\n\nRaw response:\n\n" . $json,
             $exception->getMessage(),
         );
     }
@@ -115,4 +74,23 @@ public static function partialUserFacingMessages(): \Generator
             'This event has insufficient customer information.',
         ];
     }
+
+    /**
+     * @test
+     */
+    public function it_describes_a_response_that_is_not_in_metas_error_format(): void
+    {
+        $previous = new InvalidArgumentException('not json');
+
+        $exception = new ResponseException(502, '<html>Bad Gateway</html>', null, $previous);
+
+        self::assertSame(502, $exception->statusCode);
+        self::assertSame('<html>Bad Gateway</html>', $exception->body);
+        self::assertNull($exception->errorResponse);
+        self::assertSame($previous, $exception->getPrevious());
+        self::assertSame(
+            "Meta/Facebook responded with status code 502 and a body that is not in the expected error format:\n\n<html>Bad Gateway</html>",
+            $exception->getMessage(),
+        );
+    }
 }
diff --git a/tests/Exception/TransportExceptionTest.php b/tests/Exception/TransportExceptionTest.php
new file mode 100644
index 0000000..71d07d8
--- /dev/null
+++ b/tests/Exception/TransportExceptionTest.php
@@ -0,0 +1,26 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Setono\MetaConversionsApi\Exception;
+
+use PHPUnit\Framework\TestCase;
+use Psr\Http\Client\ClientExceptionInterface;
+
+final class TransportExceptionTest extends TestCase
+{
+    /**
+     * @test
+     */
+    public function it_wraps_the_exception_from_the_http_client(): void
+    {
+        $previous = new class('Connection timed out') extends \RuntimeException implements ClientExceptionInterface {
+        };
+
+        $exception = new TransportException($previous);
+
+        self::assertSame('The request to Meta/Facebook failed: Connection timed out', $exception->getMessage());
+        self::assertSame(0, $exception->getCode());
+        self::assertSame($previous, $exception->getPrevious());
+    }
+}
diff --git a/tests/Generator/FbqGeneratorTest.php b/tests/Generator/FbqGeneratorTest.php
index c2bc7a7..c24c769 100644
--- a/tests/Generator/FbqGeneratorTest.php
+++ b/tests/Generator/FbqGeneratorTest.php
@@ -118,4 +118,21 @@ public function it_logs_an_error_and_returns_an_empty_string_when_the_user_data_
         self::assertSame('', $generator->generateInit([new Pixel('111')], ['em' => "\xB1\x31"]));
         self::assertTrue($logger->hasMessageMatching('/Malformed UTF-8 characters/'));
     }
+
+    /**
+     * @test
+     */
+    public function it_logs_an_error_and_returns_an_empty_string_when_the_custom_data_cannot_be_encoded(): void
+    {
+        $logger = new TestLogger();
+
+        $generator = new FbqGenerator();
+        $generator->setLogger($logger);
+
+        $event = new Event(Event::EVENT_PURCHASE);
+        $event->customData->customProperties['my_custom'] = "\xB1\x31"; // malformed UTF-8 cannot be JSON encoded
+
+        self::assertSame('', $generator->generateTrack($event));
+        self::assertTrue($logger->hasMessageMatching('/Malformed UTF-8 characters/'));
+    }
 }
diff --git a/tests/ValueObject/FbTest.php b/tests/ValueObject/FbTest.php
index 78f6793..307d9ed 100644
--- a/tests/ValueObject/FbTest.php
+++ b/tests/ValueObject/FbTest.php
@@ -5,6 +5,7 @@
 namespace Setono\MetaConversionsApi\ValueObject;
 
 use PHPUnit\Framework\TestCase;
+use Setono\MetaConversionsApi\Exception\InvalidArgumentException;
 
 /**
  * Fb is abstract, so the behaviour it shares between Fbc and Fbp is tested through Fbp
@@ -58,7 +59,7 @@ public static function subdomainIndexes(): \Generator
      */
     public function it_rejects_an_invalid_subdomain_index(int $subdomainIndex): void
     {
-        $this->expectException(\InvalidArgumentException::class);
+        $this->expectException(InvalidArgumentException::class);
 
         (new Fbp())->withSubdomainIndex($subdomainIndex);
     }
@@ -108,7 +109,7 @@ public function it_accepts_creation_times_between_the_founding_of_facebook_and_n
      */
     public function it_rejects_a_creation_time_out_of_range(int $creationTime): void
     {
-        $this->expectException(\InvalidArgumentException::class);
+        $this->expectException(InvalidArgumentException::class);
 
         (new Fbp())->withCreationTime($creationTime);
     }
@@ -127,7 +128,7 @@ public static function creationTimesOutOfRange(): \Generator
      */
     public function it_rejects_a_creation_time_that_is_neither_an_integer_nor_a_datetime(): void
     {
-        $this->expectException(\InvalidArgumentException::class);
+        $this->expectException(InvalidArgumentException::class);
 
         (new Fbp())->withCreationTime('1656874832584'); // @phpstan-ignore argument.type
     }
@@ -175,7 +176,7 @@ public function it_removes_the_appendix(): void
      */
     public function it_rejects_an_invalid_appendix(string $appendix): void
     {
-        $this->expectException(\InvalidArgumentException::class);
+        $this->expectException(InvalidArgumentException::class);
 
         (new Fbp())->withAppendix($appendix);
     }
diff --git a/tests/ValueObject/FbcTest.php b/tests/ValueObject/FbcTest.php
index 8c073e1..fd7f057 100644
--- a/tests/ValueObject/FbcTest.php
+++ b/tests/ValueObject/FbcTest.php
@@ -5,6 +5,7 @@
 namespace Setono\MetaConversionsApi\ValueObject;
 
 use PHPUnit\Framework\TestCase;
+use Setono\MetaConversionsApi\Exception\InvalidArgumentException;
 
 final class FbcTest extends TestCase
 {
@@ -70,7 +71,7 @@ public function it_has_immutable_creation_time_setter(): void
      */
     public function it_handles_wrong_input(string $input): void
     {
-        $this->expectException(\InvalidArgumentException::class);
+        $this->expectException(InvalidArgumentException::class);
         Fbc::fromString($input);
     }
 
diff --git a/tests/ValueObject/FbpTest.php b/tests/ValueObject/FbpTest.php
index 537de3b..c0f4038 100644
--- a/tests/ValueObject/FbpTest.php
+++ b/tests/ValueObject/FbpTest.php
@@ -5,6 +5,7 @@
 namespace Setono\MetaConversionsApi\ValueObject;
 
 use PHPUnit\Framework\TestCase;
+use Setono\MetaConversionsApi\Exception\InvalidArgumentException;
 
 final class FbpTest extends TestCase
 {
@@ -50,7 +51,7 @@ public function it_has_immutable_setters(): void
      */
     public function it_handles_wrong_input(string $input): void
     {
-        $this->expectException(\InvalidArgumentException::class);
+        $this->expectException(InvalidArgumentException::class);
         Fbp::fromString($input);
     }