diff --git a/README.md b/README.md
index 6546680..ea81106 100644
--- a/README.md
+++ b/README.md
@@ -25,8 +25,8 @@ composer require mathiasgrimm/glimpse-php
 ```
 
 ```php
-use GlimpseImg\Client;
-use GlimpseImg\ImageFormat;
+use MathiasGrimm\GlimpsePhp\Client;
+use MathiasGrimm\GlimpsePhp\ImageFormat;
 use Illuminate\Http\Client\Factory;
 
 $glimpse = new Client(new Factory, 'your-api-token');
diff --git a/composer.json b/composer.json
index e8badbc..1818bcb 100644
--- a/composer.json
+++ b/composer.json
@@ -30,12 +30,12 @@
     },
     "autoload": {
         "psr-4": {
-            "GlimpseImg\\": "src/"
+            "MathiasGrimm\\GlimpsePhp\\": "src/"
         }
     },
     "autoload-dev": {
         "psr-4": {
-            "GlimpseImg\\Tests\\": "tests/"
+            "MathiasGrimm\\GlimpsePhp\\Tests\\": "tests/"
         }
     },
     "scripts": {
diff --git a/src/ApiException.php b/src/ApiException.php
index 9fadcf3..fd634f0 100644
--- a/src/ApiException.php
+++ b/src/ApiException.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace GlimpseImg;
+namespace MathiasGrimm\GlimpsePhp;
 
 use RuntimeException;
 
diff --git a/src/AuthException.php b/src/AuthException.php
index cef3033..9d65c20 100644
--- a/src/AuthException.php
+++ b/src/AuthException.php
@@ -1,5 +1,5 @@
 <?php
 
-namespace GlimpseImg;
+namespace MathiasGrimm\GlimpsePhp;
 
 class AuthException extends ApiException {}
diff --git a/src/Client.php b/src/Client.php
index dbb1710..cbfa58f 100644
--- a/src/Client.php
+++ b/src/Client.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace GlimpseImg;
+namespace MathiasGrimm\GlimpsePhp;
 
 use Closure;
 use Illuminate\Http\Client\Factory;
@@ -138,6 +138,14 @@ private function guard(Response $response): Response
             throw new AuthException('Invalid or missing token.');
         }
 
+        if ($response->status() === 403) {
+            $message = $response->json('message');
+
+            throw new ForbiddenException(
+                is_string($message) && $message !== '' ? $message : 'This token may not call this endpoint.',
+            );
+        }
+
         if ($response->status() === 422) {
             $message = $response->json('message');
             $errors = $response->json('errors');
@@ -148,6 +156,15 @@ private function guard(Response $response): Response
             );
         }
 
+        if ($response->status() === 429) {
+            $message = $response->json('message');
+
+            throw new RateLimitException(
+                is_string($message) && $message !== '' ? $message : 'The API rate limit was reached.',
+                $this->retryAfterSeconds($response),
+            );
+        }
+
         if ($response->failed()) {
             $message = $response->json('message');
 
@@ -161,6 +178,29 @@ private function guard(Response $response): Response
         return $response;
     }
 
+    /**
+     * Parse the Retry-After header, which RFC 9110 allows as either
+     * delay-seconds or an HTTP date. Negative and fractional delays are
+     * clamped so a caller can sleep the value as-is; an absent or
+     * unparseable header yields null.
+     */
+    private function retryAfterSeconds(Response $response): ?int
+    {
+        $header = $response->header('Retry-After');
+
+        if ($header === '') {
+            return null;
+        }
+
+        if (is_numeric($header)) {
+            return max(0, (int) ceil((float) $header));
+        }
+
+        $timestamp = strtotime($header);
+
+        return $timestamp === false ? null : max(0, $timestamp - time());
+    }
+
     private function requireToken(): string
     {
         $token = $this->token instanceof Closure ? ($this->token)() : $this->token;
diff --git a/src/ForbiddenException.php b/src/ForbiddenException.php
new file mode 100644
index 0000000..0c27c89
--- /dev/null
+++ b/src/ForbiddenException.php
@@ -0,0 +1,5 @@
+<?php
+
+namespace MathiasGrimm\GlimpsePhp;
+
+class ForbiddenException extends ApiException {}
diff --git a/src/FrameCounter.php b/src/FrameCounter.php
index fe1de2e..3e73ff1 100644
--- a/src/FrameCounter.php
+++ b/src/FrameCounter.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace GlimpseImg;
+namespace MathiasGrimm\GlimpsePhp;
 
 use Imagick;
 use ImagickException;
diff --git a/src/ImageFormat.php b/src/ImageFormat.php
index 448212f..68d4eac 100644
--- a/src/ImageFormat.php
+++ b/src/ImageFormat.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace GlimpseImg;
+namespace MathiasGrimm\GlimpsePhp;
 
 enum ImageFormat: string
 {
diff --git a/src/ImageInfo.php b/src/ImageInfo.php
index 1c880ea..0baa0a7 100644
--- a/src/ImageInfo.php
+++ b/src/ImageInfo.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace GlimpseImg;
+namespace MathiasGrimm\GlimpsePhp;
 
 final readonly class ImageInfo
 {
diff --git a/src/ImageResolution.php b/src/ImageResolution.php
index e72fbf4..4a25192 100644
--- a/src/ImageResolution.php
+++ b/src/ImageResolution.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace GlimpseImg;
+namespace MathiasGrimm\GlimpsePhp;
 
 final readonly class ImageResolution
 {
diff --git a/src/ImageResult.php b/src/ImageResult.php
index 71c5441..ecb9a4c 100644
--- a/src/ImageResult.php
+++ b/src/ImageResult.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace GlimpseImg;
+namespace MathiasGrimm\GlimpsePhp;
 
 final readonly class ImageResult
 {
diff --git a/src/ProbeResult.php b/src/ProbeResult.php
index 48cde8b..8e037a9 100644
--- a/src/ProbeResult.php
+++ b/src/ProbeResult.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace GlimpseImg;
+namespace MathiasGrimm\GlimpsePhp;
 
 final readonly class ProbeResult
 {
diff --git a/src/RateLimitException.php b/src/RateLimitException.php
new file mode 100644
index 0000000..387df8f
--- /dev/null
+++ b/src/RateLimitException.php
@@ -0,0 +1,14 @@
+<?php
+
+namespace MathiasGrimm\GlimpsePhp;
+
+class RateLimitException extends ApiException
+{
+    /**
+     * @param  ?int  $retryAfterSeconds  Seconds to wait from the Retry-After header (never negative), or null when the header is missing or unparseable
+     */
+    public function __construct(string $message, public readonly ?int $retryAfterSeconds = null)
+    {
+        parent::__construct($message);
+    }
+}
diff --git a/src/SampleProbe.php b/src/SampleProbe.php
index a511d50..10af4cc 100644
--- a/src/SampleProbe.php
+++ b/src/SampleProbe.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace GlimpseImg;
+namespace MathiasGrimm\GlimpsePhp;
 
 use Imagick;
 use ImagickException;
diff --git a/src/SizeEstimate.php b/src/SizeEstimate.php
index fdaa7c0..b0ebb44 100644
--- a/src/SizeEstimate.php
+++ b/src/SizeEstimate.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace GlimpseImg;
+namespace MathiasGrimm\GlimpsePhp;
 
 final readonly class SizeEstimate
 {
diff --git a/src/UsagePeriod.php b/src/UsagePeriod.php
index c000661..5ae269b 100644
--- a/src/UsagePeriod.php
+++ b/src/UsagePeriod.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace GlimpseImg;
+namespace MathiasGrimm\GlimpsePhp;
 
 use DateTimeImmutable;
 use Exception;
diff --git a/src/UsageSummary.php b/src/UsageSummary.php
index 00b1a19..6f5ae7f 100644
--- a/src/UsageSummary.php
+++ b/src/UsageSummary.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace GlimpseImg;
+namespace MathiasGrimm\GlimpsePhp;
 
 final readonly class UsageSummary
 {
diff --git a/src/User.php b/src/User.php
index 05fafe4..8c7ac66 100644
--- a/src/User.php
+++ b/src/User.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace GlimpseImg;
+namespace MathiasGrimm\GlimpsePhp;
 
 use DateTimeImmutable;
 use Exception;
diff --git a/src/ValidationException.php b/src/ValidationException.php
index c893ba9..cef7cc6 100644
--- a/src/ValidationException.php
+++ b/src/ValidationException.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace GlimpseImg;
+namespace MathiasGrimm\GlimpsePhp;
 
 class ValidationException extends ApiException
 {
diff --git a/tests/ClientTest.php b/tests/ClientTest.php
index bbd6acf..c9ed9dd 100644
--- a/tests/ClientTest.php
+++ b/tests/ClientTest.php
@@ -1,17 +1,19 @@
 <?php
 
-use GlimpseImg\ApiException;
-use GlimpseImg\AuthException;
-use GlimpseImg\Client;
-use GlimpseImg\ImageFormat;
-use GlimpseImg\ImageInfo;
-use GlimpseImg\SizeEstimate;
-use GlimpseImg\Tests\Fixtures\Images;
-use GlimpseImg\UsageSummary;
-use GlimpseImg\User;
-use GlimpseImg\ValidationException;
 use Illuminate\Http\Client\Factory;
 use Illuminate\Http\Client\Request;
+use MathiasGrimm\GlimpsePhp\ApiException;
+use MathiasGrimm\GlimpsePhp\AuthException;
+use MathiasGrimm\GlimpsePhp\Client;
+use MathiasGrimm\GlimpsePhp\ForbiddenException;
+use MathiasGrimm\GlimpsePhp\ImageFormat;
+use MathiasGrimm\GlimpsePhp\ImageInfo;
+use MathiasGrimm\GlimpsePhp\RateLimitException;
+use MathiasGrimm\GlimpsePhp\SizeEstimate;
+use MathiasGrimm\GlimpsePhp\Tests\Fixtures\Images;
+use MathiasGrimm\GlimpsePhp\UsageSummary;
+use MathiasGrimm\GlimpsePhp\User;
+use MathiasGrimm\GlimpsePhp\ValidationException;
 
 function fakeHttp(array $responses = []): Factory
 {
@@ -364,6 +366,87 @@ function client(Factory $http, Closure|string|null $token = 'test-token', string
     }
 });
 
+test('a 403 response maps to ForbiddenException with the API message', function () {
+    $http = fakeHttp(['*/v1/convert' => Factory::response(['message' => 'Invalid ability provided.'], 403)]);
+
+    expect(fn () => client($http)->convert(Images::png(), ImageFormat::Jpg))
+        ->toThrow(ForbiddenException::class, 'Invalid ability provided.');
+});
+
+test('a 403 response without a message gets the fallback text', function () {
+    $http = fakeHttp(['*/v1/convert' => Factory::response([], 403)]);
+
+    expect(fn () => client($http)->convert(Images::png(), ImageFormat::Jpg))
+        ->toThrow(ForbiddenException::class, 'This token may not call this endpoint.');
+});
+
+test('a 429 response maps to RateLimitException carrying Retry-After', function () {
+    $http = fakeHttp(['*/v1/analyze' => Factory::response(['message' => 'Too Many Requests'], 429, ['Retry-After' => '17'])]);
+
+    try {
+        client($http)->analyze(ImageFormat::Jpg, 2_500_000);
+        $this->fail('Expected a RateLimitException.');
+    } catch (RateLimitException $e) {
+        expect($e->getMessage())->toBe('Too Many Requests')
+            ->and($e->retryAfterSeconds)->toBe(17);
+    }
+});
+
+test('a 429 response without a Retry-After header yields a null delay', function () {
+    $http = fakeHttp(['*/v1/analyze' => Factory::response(['message' => 'Too Many Requests'], 429)]);
+
+    try {
+        client($http)->analyze(ImageFormat::Jpg, 2_500_000);
+        $this->fail('Expected a RateLimitException.');
+    } catch (RateLimitException $e) {
+        expect($e->retryAfterSeconds)->toBeNull();
+    }
+});
+
+test('a 429 response prefers the API message over the fallback', function () {
+    $http = fakeHttp(['*/v1/analyze' => Factory::response(['message' => 'Shared token limit reached.'], 429)]);
+
+    expect(fn () => client($http)->analyze(ImageFormat::Jpg, 2_500_000))
+        ->toThrow(RateLimitException::class, 'Shared token limit reached.');
+});
+
+test('Retry-After parsing clamps and rounds odd delay values', function (string $header, ?int $expected) {
+    $http = fakeHttp(['*/v1/analyze' => Factory::response([], 429, ['Retry-After' => $header])]);
+
+    try {
+        client($http)->analyze(ImageFormat::Jpg, 2_500_000);
+        $this->fail('Expected a RateLimitException.');
+    } catch (RateLimitException $e) {
+        expect($e->retryAfterSeconds)->toBe($expected);
+    }
+})->with([
+    'negative clamps to zero' => ['-5', 0],
+    'fractional rounds up' => ['2.5', 3],
+    'garbage yields null' => ['soon', null],
+]);
+
+test('an HTTP-date Retry-After resolves to the remaining seconds', function () {
+    $http = fakeHttp(['*/v1/analyze' => Factory::response([], 429, [
+        'Retry-After' => gmdate('D, d M Y H:i:s \G\M\T', time() + 30),
+    ])]);
+
+    try {
+        client($http)->analyze(ImageFormat::Jpg, 2_500_000);
+        $this->fail('Expected a RateLimitException.');
+    } catch (RateLimitException $e) {
+        expect($e->retryAfterSeconds)->toBeGreaterThanOrEqual(28)
+            ->and($e->retryAfterSeconds)->toBeLessThanOrEqual(30);
+    }
+});
+
+test('the new exceptions stay catchable as ApiException', function () {
+    $limited = fakeHttp(['*/v1/analyze' => Factory::response([], 429)]);
+    $forbidden = fakeHttp(['*/v1/convert' => Factory::response([], 403)]);
+
+    expect(fn () => client($limited)->analyze(ImageFormat::Jpg, 2_500_000))->toThrow(ApiException::class)
+        ->and(fn () => client($forbidden)->convert(Images::png(), ImageFormat::Jpg))->toThrow(ApiException::class);
+});
+
 test('other failures map to ApiException with the status code', function () {
     $http = fakeHttp(['*/v1/optimize' => Factory::response(['message' => 'Server Error'], 500)]);
 
diff --git a/tests/Fixtures/Images.php b/tests/Fixtures/Images.php
index b620400..e6776db 100644
--- a/tests/Fixtures/Images.php
+++ b/tests/Fixtures/Images.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace GlimpseImg\Tests\Fixtures;
+namespace MathiasGrimm\GlimpsePhp\Tests\Fixtures;
 
 final class Images
 {
diff --git a/tests/FrameCounterTest.php b/tests/FrameCounterTest.php
index 6d8abd3..1d811e8 100644
--- a/tests/FrameCounterTest.php
+++ b/tests/FrameCounterTest.php
@@ -1,7 +1,7 @@
 <?php
 
-use GlimpseImg\FrameCounter;
-use GlimpseImg\Tests\Fixtures\Images;
+use MathiasGrimm\GlimpsePhp\FrameCounter;
+use MathiasGrimm\GlimpsePhp\Tests\Fixtures\Images;
 
 test('counts the frames of an animated gif without any image extension', function () {
     expect((new FrameCounter)->count(Images::animatedGif()))->toBe(3);
diff --git a/tests/ImageFormatTest.php b/tests/ImageFormatTest.php
index 3a72f37..0753b10 100644
--- a/tests/ImageFormatTest.php
+++ b/tests/ImageFormatTest.php
@@ -1,7 +1,7 @@
 <?php
 
-use GlimpseImg\ImageFormat;
-use GlimpseImg\Tests\Fixtures\Images;
+use MathiasGrimm\GlimpsePhp\ImageFormat;
+use MathiasGrimm\GlimpsePhp\Tests\Fixtures\Images;
 
 test('tryFromBinary detects each supported format by its magic numbers', function () {
     expect(ImageFormat::tryFromBinary(Images::jpg()))->toBe(ImageFormat::Jpg)
diff --git a/tests/Pest.php b/tests/Pest.php
index d7a1b24..ccab4f9 100644
--- a/tests/Pest.php
+++ b/tests/Pest.php
@@ -1,6 +1,6 @@
 <?php
 
-use GlimpseImg\Tests\Fixtures\Images;
+use MathiasGrimm\GlimpsePhp\Tests\Fixtures\Images;
 
 /**
  * A canned successful analyze-endpoint response envelope.
diff --git a/tests/SampleProbeTest.php b/tests/SampleProbeTest.php
index e1dee76..6a221af 100644
--- a/tests/SampleProbeTest.php
+++ b/tests/SampleProbeTest.php
@@ -1,7 +1,7 @@
 <?php
 
-use GlimpseImg\SampleProbe;
-use GlimpseImg\Tests\Fixtures\Images;
+use MathiasGrimm\GlimpsePhp\SampleProbe;
+use MathiasGrimm\GlimpsePhp\Tests\Fixtures\Images;
 
 /**
  * Generate a jpeg whose content complexity is controlled: noisy pixels