diff --git a/app/Exceptions/Social/LinkedInPublishException.php b/app/Exceptions/Social/LinkedInPublishException.php
new file mode 100644
index 00000000..aad4a088
--- /dev/null
+++ b/app/Exceptions/Social/LinkedInPublishException.php
@@ -0,0 +1,64 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Exceptions\Social;
+
+use App\Exceptions\TokenExpiredException;
+use Illuminate\Http\Client\Response;
+
+class LinkedInPublishException extends SocialPublishException
+{
+    public static function fromApiResponse(mixed $response): static
+    {
+        /** @var Response $response */
+        $body = $response->json();
+        $rawResponse = $response->body();
+        $statusCode = $response->status();
+
+        $errorMessage = data_get($body, 'message', $rawResponse);
+
+        if ($statusCode === 401) {
+            throw new TokenExpiredException(
+                message: $errorMessage ?? 'Access token has expired or been revoked',
+                platformErrorCode: (string) $statusCode,
+            );
+        }
+
+        if (str_contains((string) $rawResponse, 'Unable to obtain activity')) {
+            return new static(
+                userMessage: 'LinkedIn server error. Please try again.',
+                category: ErrorCategory::ServerError,
+                platformErrorCode: (string) $statusCode,
+                rawResponse: $rawResponse,
+            );
+        }
+
+        if (str_contains((string) $rawResponse, 'resource is forbidden')) {
+            return new static(
+                userMessage: 'Not authorized to post to this account.',
+                category: ErrorCategory::Permission,
+                platformErrorCode: (string) $statusCode,
+                rawResponse: $rawResponse,
+            );
+        }
+
+        [$message, $category] = match ($statusCode) {
+            403 => ['Not authorized to post to this account.', ErrorCategory::Permission],
+            422 => ['Invalid post data. Please check your content.', ErrorCategory::ContentPolicy],
+            default => [$errorMessage ?? 'An unknown LinkedIn error occurred.', ErrorCategory::Unknown],
+        };
+
+        return new static(
+            userMessage: $message,
+            category: $category,
+            platformErrorCode: (string) $statusCode,
+            rawResponse: $rawResponse,
+        );
+    }
+
+    public function platform(): string
+    {
+        return 'linkedin';
+    }
+}
diff --git a/app/Exceptions/Social/ThreadsPublishException.php b/app/Exceptions/Social/ThreadsPublishException.php
new file mode 100644
index 00000000..1a2026f2
--- /dev/null
+++ b/app/Exceptions/Social/ThreadsPublishException.php
@@ -0,0 +1,69 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Exceptions\Social;
+
+use App\Exceptions\TokenExpiredException;
+use Illuminate\Http\Client\Response;
+
+class ThreadsPublishException extends SocialPublishException
+{
+    public static function fromApiResponse(mixed $response): static
+    {
+        /** @var Response $response */
+        $body = $response->json();
+        $rawResponse = $response->body();
+        $statusCode = $response->status();
+
+        $errorType = data_get($body, 'error.type');
+        $errorCode = data_get($body, 'error.code');
+        $errorMessage = data_get($body, 'error.message', 'An unknown Threads error occurred.');
+
+        if ($errorType === 'OAuthException' || $errorCode === 190) {
+            throw new TokenExpiredException(
+                message: $errorMessage,
+                platformErrorCode: $errorCode !== null ? (string) $errorCode : null,
+            );
+        }
+
+        if (stripos((string) $rawResponse, "text can't be blank") !== false) {
+            return new static(
+                userMessage: 'Post text is required.',
+                category: ErrorCategory::ContentPolicy,
+                platformErrorCode: $errorCode !== null ? (string) $errorCode : null,
+                rawResponse: $rawResponse,
+            );
+        }
+
+        if ($statusCode === 429) {
+            return new static(
+                userMessage: 'Rate limit exceeded. Please try again later.',
+                category: ErrorCategory::RateLimit,
+                platformErrorCode: (string) $statusCode,
+                rawResponse: $rawResponse,
+            );
+        }
+
+        if ($statusCode >= 500) {
+            return new static(
+                userMessage: 'Threads server error. Please try again.',
+                category: ErrorCategory::ServerError,
+                platformErrorCode: (string) $statusCode,
+                rawResponse: $rawResponse,
+            );
+        }
+
+        return new static(
+            userMessage: $errorMessage,
+            category: ErrorCategory::Unknown,
+            platformErrorCode: $errorCode !== null ? (string) $errorCode : null,
+            rawResponse: $rawResponse,
+        );
+    }
+
+    public function platform(): string
+    {
+        return 'threads';
+    }
+}
diff --git a/app/Exceptions/Social/XPublishException.php b/app/Exceptions/Social/XPublishException.php
new file mode 100644
index 00000000..97f8dd18
--- /dev/null
+++ b/app/Exceptions/Social/XPublishException.php
@@ -0,0 +1,81 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Exceptions\Social;
+
+use App\Exceptions\TokenExpiredException;
+use Illuminate\Http\Client\Response;
+
+class XPublishException extends SocialPublishException
+{
+    public static function fromApiResponse(mixed $response): static
+    {
+        /** @var Response $response */
+        $body = $response->json();
+        $rawResponse = $response->body();
+        $statusCode = $response->status();
+
+        $type = data_get($body, 'type', '');
+        $title = data_get($body, 'title', '');
+        $detail = data_get($body, 'detail', $title);
+
+        $typeSuffix = $type !== '' ? basename((string) $type) : '';
+
+        if ($statusCode === 401 || str_contains((string) $type, 'unsupported-authentication')) {
+            throw new TokenExpiredException(
+                message: $detail ?: 'Access token has expired or been revoked',
+                platformErrorCode: $typeSuffix ?: (string) $statusCode,
+            );
+        }
+
+        if (str_contains((string) $rawResponse, 'invalid URL')) {
+            return new static(
+                userMessage: 'Post contains an invalid URL.',
+                category: ErrorCategory::ContentPolicy,
+                platformErrorCode: $typeSuffix ?: null,
+                rawResponse: $rawResponse,
+            );
+        }
+
+        if (str_contains((string) $rawResponse, 'video longer than 2 minutes')) {
+            return new static(
+                userMessage: 'Video exceeds the 2-minute limit.',
+                category: ErrorCategory::MediaFormat,
+                platformErrorCode: $typeSuffix ?: null,
+                rawResponse: $rawResponse,
+            );
+        }
+
+        if (in_array($statusCode, [500, 502, 503, 504], true)) {
+            return new static(
+                userMessage: 'X server error. Please try again later.',
+                category: ErrorCategory::ServerError,
+                platformErrorCode: (string) $statusCode,
+                rawResponse: $rawResponse,
+            );
+        }
+
+        [$message, $category] = match ($typeSuffix) {
+            'usage-capped' => ['Usage limit exceeded. Please try again later.', ErrorCategory::RateLimit],
+            'rate-limit-exceeded' => ['Rate limit exceeded. Please try again later.', ErrorCategory::RateLimit],
+            'invalid-request' => ['Invalid request. Check your post content.', ErrorCategory::ContentPolicy],
+            'client-forbidden' => ['App not enrolled or lacks required access.', ErrorCategory::Permission],
+            'not-authorized-for-resource' => ['Not authorized for this resource.', ErrorCategory::Permission],
+            'resource-not-found' => ['Resource not found.', ErrorCategory::ContentPolicy],
+            default => [$detail ?: $title ?: 'An unknown X error occurred.', ErrorCategory::Unknown],
+        };
+
+        return new static(
+            userMessage: $message,
+            category: $category,
+            platformErrorCode: $typeSuffix ?: null,
+            rawResponse: $rawResponse,
+        );
+    }
+
+    public function platform(): string
+    {
+        return 'x';
+    }
+}
diff --git a/tests/Unit/Exceptions/Social/LinkedInPublishExceptionTest.php b/tests/Unit/Exceptions/Social/LinkedInPublishExceptionTest.php
new file mode 100644
index 00000000..26d9f7a4
--- /dev/null
+++ b/tests/Unit/Exceptions/Social/LinkedInPublishExceptionTest.php
@@ -0,0 +1,83 @@
+<?php
+
+declare(strict_types=1);
+
+use App\Exceptions\Social\ErrorCategory;
+use App\Exceptions\Social\LinkedInPublishException;
+use App\Exceptions\TokenExpiredException;
+use Illuminate\Support\Facades\Http;
+
+test('HTTP 401 throws TokenExpiredException', function () {
+    $response = Http::response(['message' => 'Unauthorized'], 401);
+
+    $fakeResponse = Http::fake(['*' => $response])->post('https://api.linkedin.com/test');
+
+    LinkedInPublishException::fromApiResponse($fakeResponse);
+})->throws(TokenExpiredException::class);
+
+test('HTTP 403 maps to Permission category', function () {
+    $response = Http::response(['message' => 'Forbidden'], 403);
+
+    $fakeResponse = Http::fake(['*' => $response])->post('https://api.linkedin.com/test');
+
+    $exception = LinkedInPublishException::fromApiResponse($fakeResponse);
+
+    expect($exception)
+        ->toBeInstanceOf(LinkedInPublishException::class)
+        ->and($exception->category)->toBe(ErrorCategory::Permission)
+        ->and($exception->userMessage)->toBe('Not authorized to post to this account.');
+});
+
+test('body containing "Unable to obtain activity" maps to ServerError category', function () {
+    $response = Http::response(['message' => 'Unable to obtain activity for URN'], 400);
+
+    $fakeResponse = Http::fake(['*' => $response])->post('https://api.linkedin.com/test');
+
+    $exception = LinkedInPublishException::fromApiResponse($fakeResponse);
+
+    expect($exception->category)->toBe(ErrorCategory::ServerError)
+        ->and($exception->userMessage)->toBe('LinkedIn server error. Please try again.');
+});
+
+test('unknown error maps to Unknown category with response body as message', function () {
+    $response = Http::response(['message' => 'Something went wrong.'], 400);
+
+    $fakeResponse = Http::fake(['*' => $response])->post('https://api.linkedin.com/test');
+
+    $exception = LinkedInPublishException::fromApiResponse($fakeResponse);
+
+    expect($exception->category)->toBe(ErrorCategory::Unknown)
+        ->and($exception->userMessage)->toBe('Something went wrong.');
+});
+
+test('HTTP 422 maps to ContentPolicy category', function () {
+    $response = Http::response(['message' => 'Validation error'], 422);
+
+    $fakeResponse = Http::fake(['*' => $response])->post('https://api.linkedin.com/test');
+
+    $exception = LinkedInPublishException::fromApiResponse($fakeResponse);
+
+    expect($exception->category)->toBe(ErrorCategory::ContentPolicy)
+        ->and($exception->userMessage)->toBe('Invalid post data. Please check your content.');
+});
+
+test('body containing "resource is forbidden" maps to Permission category', function () {
+    $response = Http::response(['message' => 'The resource is forbidden'], 403);
+
+    $fakeResponse = Http::fake(['*' => $response])->post('https://api.linkedin.com/test');
+
+    $exception = LinkedInPublishException::fromApiResponse($fakeResponse);
+
+    expect($exception->category)->toBe(ErrorCategory::Permission)
+        ->and($exception->userMessage)->toBe('Not authorized to post to this account.');
+});
+
+test('platform returns linkedin', function () {
+    $response = Http::response(['message' => 'Some error'], 400);
+
+    $fakeResponse = Http::fake(['*' => $response])->post('https://api.linkedin.com/test');
+
+    $exception = LinkedInPublishException::fromApiResponse($fakeResponse);
+
+    expect($exception->platform())->toBe('linkedin');
+});
diff --git a/tests/Unit/Exceptions/Social/ThreadsPublishExceptionTest.php b/tests/Unit/Exceptions/Social/ThreadsPublishExceptionTest.php
new file mode 100644
index 00000000..80d6ab3a
--- /dev/null
+++ b/tests/Unit/Exceptions/Social/ThreadsPublishExceptionTest.php
@@ -0,0 +1,138 @@
+<?php
+
+declare(strict_types=1);
+
+use App\Exceptions\Social\ErrorCategory;
+use App\Exceptions\Social\ThreadsPublishException;
+use App\Exceptions\TokenExpiredException;
+use Illuminate\Support\Facades\Http;
+
+test('OAuthException type throws TokenExpiredException', function () {
+    $response = Http::response([
+        'error' => [
+            'message' => 'Invalid OAuth access token.',
+            'type' => 'OAuthException',
+            'code' => 190,
+        ],
+    ], 400);
+
+    $fakeResponse = Http::fake(['*' => $response])->post('https://graph.threads.net/test');
+
+    ThreadsPublishException::fromApiResponse($fakeResponse);
+})->throws(TokenExpiredException::class);
+
+test('error code 190 throws TokenExpiredException', function () {
+    $response = Http::response([
+        'error' => [
+            'message' => 'Access token expired.',
+            'type' => 'ThreadsException',
+            'code' => 190,
+        ],
+    ], 400);
+
+    $fakeResponse = Http::fake(['*' => $response])->post('https://graph.threads.net/test');
+
+    ThreadsPublishException::fromApiResponse($fakeResponse);
+})->throws(TokenExpiredException::class);
+
+test('HTTP 429 maps to RateLimit category', function () {
+    $response = Http::response([
+        'error' => [
+            'message' => 'Application request limit reached.',
+            'type' => 'ThreadsException',
+            'code' => 4,
+        ],
+    ], 429);
+
+    $fakeResponse = Http::fake(['*' => $response])->post('https://graph.threads.net/test');
+
+    $exception = ThreadsPublishException::fromApiResponse($fakeResponse);
+
+    expect($exception)
+        ->toBeInstanceOf(ThreadsPublishException::class)
+        ->and($exception->category)->toBe(ErrorCategory::RateLimit)
+        ->and($exception->userMessage)->toBe('Rate limit exceeded. Please try again later.');
+});
+
+test('body containing "text can\'t be blank" maps to ContentPolicy category', function () {
+    $response = Http::response([
+        'error' => [
+            'message' => "text can't be blank",
+            'type' => 'ThreadsException',
+            'code' => 100,
+        ],
+    ], 400);
+
+    $fakeResponse = Http::fake(['*' => $response])->post('https://graph.threads.net/test');
+
+    $exception = ThreadsPublishException::fromApiResponse($fakeResponse);
+
+    expect($exception->category)->toBe(ErrorCategory::ContentPolicy)
+        ->and($exception->userMessage)->toBe('Post text is required.');
+});
+
+test('"text can\'t be blank" check is case insensitive', function () {
+    $response = Http::response([
+        'error' => [
+            'message' => "Text Can't Be Blank",
+            'type' => 'ThreadsException',
+            'code' => 100,
+        ],
+    ], 400);
+
+    $fakeResponse = Http::fake(['*' => $response])->post('https://graph.threads.net/test');
+
+    $exception = ThreadsPublishException::fromApiResponse($fakeResponse);
+
+    expect($exception->category)->toBe(ErrorCategory::ContentPolicy);
+});
+
+test('unknown error maps to Unknown category with error message', function () {
+    $response = Http::response([
+        'error' => [
+            'message' => 'An unexpected error occurred.',
+            'type' => 'ThreadsException',
+            'code' => 9999,
+        ],
+    ], 400);
+
+    $fakeResponse = Http::fake(['*' => $response])->post('https://graph.threads.net/test');
+
+    $exception = ThreadsPublishException::fromApiResponse($fakeResponse);
+
+    expect($exception->category)->toBe(ErrorCategory::Unknown)
+        ->and($exception->userMessage)->toBe('An unexpected error occurred.');
+});
+
+test('HTTP 500 maps to ServerError category', function () {
+    $response = Http::response([
+        'error' => [
+            'message' => 'Internal server error.',
+            'type' => 'ThreadsException',
+            'code' => 1,
+        ],
+    ], 500);
+
+    $fakeResponse = Http::fake(['*' => $response])->post('https://graph.threads.net/test');
+
+    $exception = ThreadsPublishException::fromApiResponse($fakeResponse);
+
+    expect($exception->category)->toBe(ErrorCategory::ServerError)
+        ->and($exception->userMessage)->toBe('Threads server error. Please try again.');
+});
+
+test('platform returns threads', function () {
+    $response = Http::response([
+        'error' => [
+            'message' => 'Some error.',
+            'type' => 'ThreadsException',
+            'code' => 9999,
+        ],
+    ], 400);
+
+    $fakeResponse = Http::fake(['*' => $response])->post('https://graph.threads.net/test');
+
+    $exception = ThreadsPublishException::fromApiResponse($fakeResponse);
+
+    expect($exception->platform())->toBe('threads');
+});
diff --git a/tests/Unit/Exceptions/Social/XPublishExceptionTest.php b/tests/Unit/Exceptions/Social/XPublishExceptionTest.php
new file mode 100644
index 00000000..2001af07
--- /dev/null
+++ b/tests/Unit/Exceptions/Social/XPublishExceptionTest.php
@@ -0,0 +1,137 @@
+<?php
+
+declare(strict_types=1);
+
+use App\Exceptions\Social\ErrorCategory;
+use App\Exceptions\Social\XPublishException;
+use App\Exceptions\TokenExpiredException;
+use Illuminate\Support\Facades\Http;
+
+test('HTTP 401 throws TokenExpiredException', function () {
+    $response = Http::response([
+        'type' => 'https://api.x.com/2/problems/not-authorized-for-resource',
+        'title' => 'Unauthorized',
+        'detail' => 'Could not authenticate you.',
+    ], 401);
+
+    $fakeResponse = Http::fake(['*' => $response])->post('https://api.x.com/test');
+
+    XPublishException::fromApiResponse($fakeResponse);
+})->throws(TokenExpiredException::class);
+
+test('type unsupported-authentication throws TokenExpiredException', function () {
+    $response = Http::response([
+        'type' => 'https://api.x.com/2/problems/unsupported-authentication',
+        'title' => 'Unsupported Authentication',
+        'detail' => 'Authentication method not supported.',
+    ], 403);
+
+    $fakeResponse = Http::fake(['*' => $response])->post('https://api.x.com/test');
+
+    XPublishException::fromApiResponse($fakeResponse);
+})->throws(TokenExpiredException::class);
+
+test('type usage-capped maps to RateLimit category', function () {
+    $response = Http::response([
+        'type' => 'https://api.x.com/2/problems/usage-capped',
+        'title' => 'Usage Capped',
+        'detail' => 'You have exceeded your monthly usage cap.',
+    ], 403);
+
+    $fakeResponse = Http::fake(['*' => $response])->post('https://api.x.com/test');
+
+    $exception = XPublishException::fromApiResponse($fakeResponse);
+
+    expect($exception)
+        ->toBeInstanceOf(XPublishException::class)
+        ->and($exception->category)->toBe(ErrorCategory::RateLimit)
+        ->and($exception->userMessage)->toBe('Usage limit exceeded. Please try again later.');
+});
+
+test('type client-forbidden maps to Permission category', function () {
+    $response = Http::response([
+        'type' => 'https://api.x.com/2/problems/client-forbidden',
+        'title' => 'Client Forbidden',
+        'detail' => 'This app is not enrolled.',
+    ], 403);
+
+    $fakeResponse = Http::fake(['*' => $response])->post('https://api.x.com/test');
+
+    $exception = XPublishException::fromApiResponse($fakeResponse);
+
+    expect($exception->category)->toBe(ErrorCategory::Permission)
+        ->and($exception->userMessage)->toBe('App not enrolled or lacks required access.');
+});
+
+test('HTTP 500 maps to ServerError category', function () {
+    $response = Http::response([
+        'title' => 'Internal Server Error',
+        'detail' => 'Something went wrong on our end.',
+    ], 500);
+
+    $fakeResponse = Http::fake(['*' => $response])->post('https://api.x.com/test');
+
+    $exception = XPublishException::fromApiResponse($fakeResponse);
+
+    expect($exception->category)->toBe(ErrorCategory::ServerError)
+        ->and($exception->userMessage)->toBe('X server error. Please try again later.');
+});
+
+test('unknown type maps to Unknown category with detail as message', function () {
+    $response = Http::response([
+        'type' => 'https://api.x.com/2/problems/some-unknown-problem',
+        'title' => 'Some Unknown Problem',
+        'detail' => 'An unknown issue occurred.',
+    ], 400);
+
+    $fakeResponse = Http::fake(['*' => $response])->post('https://api.x.com/test');
+
+    $exception = XPublishException::fromApiResponse($fakeResponse);
+
+    expect($exception->category)->toBe(ErrorCategory::Unknown)
+        ->and($exception->userMessage)->toBe('An unknown issue occurred.');
+});
+
+test('body containing "invalid URL" maps to ContentPolicy category', function () {
+    $response = Http::response([
+        'type' => 'https://api.x.com/2/problems/invalid-request',
+        'title' => 'Invalid Request',
+        'detail' => 'The post contains an invalid URL in the content.',
+    ], 400);
+
+    $fakeResponse = Http::fake(['*' => $response])->post('https://api.x.com/test');
+
+    $exception = XPublishException::fromApiResponse($fakeResponse);
+
+    expect($exception->category)->toBe(ErrorCategory::ContentPolicy)
+        ->and($exception->userMessage)->toBe('Post contains an invalid URL.');
+});
+
+test('body containing "video longer than 2 minutes" maps to MediaFormat category', function () {
+    $response = Http::response([
+        'type' => 'https://api.x.com/2/problems/invalid-request',
+        'title' => 'Invalid Request',
+        'detail' => 'The video longer than 2 minutes cannot be uploaded.',
+    ], 400);
+
+    $fakeResponse = Http::fake(['*' => $response])->post('https://api.x.com/test');
+
+    $exception = XPublishException::fromApiResponse($fakeResponse);
+
+    expect($exception->category)->toBe(ErrorCategory::MediaFormat)
+        ->and($exception->userMessage)->toBe('Video exceeds the 2-minute limit.');
+});
+
+test('platform returns x', function () {
+    $response = Http::response([
+        'type' => 'https://api.x.com/2/problems/some-unknown-problem',
+        'title' => 'Error',
+        'detail' => 'Some detail.',
+    ], 400);
+
+    $fakeResponse = Http::fake(['*' => $response])->post('https://api.x.com/test');
+
+    $exception = XPublishException::fromApiResponse($fakeResponse);
+
+    expect($exception->platform())->toBe('x');
+});