diff --git a/Services/VendorUpdateCheckerService.php b/Services/VendorUpdateCheckerService.php
index d483c61..3fced47 100644
--- a/Services/VendorUpdateCheckerService.php
+++ b/Services/VendorUpdateCheckerService.php
@@ -6,6 +6,8 @@ namespace Core\Mod\Uptelligence\Services;
 
 use Core\Mod\Uptelligence\Models\UpstreamTodo;
 use Core\Mod\Uptelligence\Models\Vendor;
+use Illuminate\Http\Client\ConnectionException;
+use Illuminate\Http\Client\RequestException;
 use Illuminate\Support\Facades\Http;
 use Illuminate\Support\Facades\Log;
 use Illuminate\Support\Facades\RateLimiter;
@@ -17,6 +19,13 @@ use Illuminate\Support\Facades\RateLimiter;
  */
 class VendorUpdateCheckerService
 {
+    /**
+     * In-memory cache for AltumCode plugin versions.
+     *
+     * Avoids redundant HTTP calls when checking multiple plugins in one run.
+     */
+    protected ?array $altumPluginVersionsCache = null;
+
     /**
      * Check all active vendors for updates.
      *
@@ -42,6 +51,8 @@ class VendorUpdateCheckerService
     {
         // Determine check method based on source type and git URL
         $result = match (true) {
+            $this->isAltumPlatform($vendor) && $vendor->isLicensed() => $this->checkAltumProduct($vendor),
+            $this->isAltumPlatform($vendor) && $vendor->isPlugin() => $this->checkAltumPlugin($vendor),
             $vendor->isOss() && $this->isGitHubUrl($vendor->git_repo_url) => $this->checkGitHub($vendor),
             $vendor->isOss() && $this->isGiteaUrl($vendor->git_repo_url) => $this->checkGitea($vendor),
             default => $this->skipCheck($vendor),
@@ -89,10 +100,10 @@ class VendorUpdateCheckerService
             ->retry(3, function (int $attempt) {
                 return (int) pow(2, $attempt - 1) * 1000;
             }, function (\Exception $exception) {
-                if ($exception instanceof \Illuminate\Http\Client\ConnectionException) {
+                if ($exception instanceof ConnectionException) {
                     return true;
                 }
-                if ($exception instanceof \Illuminate\Http\Client\RequestException) {
+                if ($exception instanceof RequestException) {
                     $status = $exception->response?->status();
 
                     return $status >= 500 || $status === 429;
@@ -273,6 +284,125 @@ class VendorUpdateCheckerService
         );
     }
 
+    /**
+     * Check if vendor belongs to the AltumCode platform.
+     */
+    protected function isAltumPlatform(Vendor $vendor): bool
+    {
+        return $vendor->plugin_platform === Vendor::PLATFORM_ALTUM;
+    }
+
+    /**
+     * Check an AltumCode licensed product for updates.
+     *
+     * Fetches the product's info.php endpoint (e.g. https://66analytics.com/info.php)
+     * and reads the latest_release_version from the JSON response.
+     */
+    protected function checkAltumProduct(Vendor $vendor): array
+    {
+        $url = "https://{$vendor->slug}.com/info.php";
+
+        try {
+            $response = Http::timeout(5)->get($url);
+        } catch (\Exception $e) {
+            Log::warning('Uptelligence: AltumCode product check failed', [
+                'vendor' => $vendor->slug,
+                'url' => $url,
+                'error' => $e->getMessage(),
+            ]);
+
+            return $this->errorResult("AltumCode product check failed: {$e->getMessage()}");
+        }
+
+        if (! $response->successful()) {
+            Log::warning('Uptelligence: AltumCode product info request failed', [
+                'vendor' => $vendor->slug,
+                'status' => $response->status(),
+            ]);
+
+            return $this->errorResult("AltumCode product info error: {$response->status()}");
+        }
+
+        $data = $response->json();
+        $latestVersion = $this->normaliseVersion($data['latest_release_version'] ?? '');
+
+        return $this->buildResult(
+            vendor: $vendor,
+            latestVersion: $latestVersion,
+            releaseInfo: [
+                'source' => 'altum_product',
+                'url' => $url,
+            ]
+        );
+    }
+
+    /**
+     * Check an AltumCode plugin for updates.
+     *
+     * Fetches the plugin versions endpoint and looks up the plugin by ID
+     * (stripping the 'altum-plugin-' prefix from the vendor slug).
+     */
+    protected function checkAltumPlugin(Vendor $vendor): array
+    {
+        $versions = $this->getAltumPluginVersions();
+
+        if ($versions === null) {
+            return $this->errorResult('Failed to fetch AltumCode plugin versions');
+        }
+
+        // Strip 'altum-plugin-' prefix from slug to get the plugin ID
+        $pluginId = str_replace('altum-plugin-', '', $vendor->slug);
+
+        if (! isset($versions[$pluginId])) {
+            return $this->errorResult("Plugin '{$pluginId}' not found in AltumCode registry");
+        }
+
+        $latestVersion = $this->normaliseVersion($versions[$pluginId]['version'] ?? '');
+
+        return $this->buildResult(
+            vendor: $vendor,
+            latestVersion: $latestVersion,
+            releaseInfo: [
+                'source' => 'altum_plugin',
+                'plugin_id' => $pluginId,
+            ]
+        );
+    }
+
+    /**
+     * Fetch AltumCode plugin versions with in-memory caching.
+     *
+     * @return array<string, array{version: string}>|null
+     */
+    protected function getAltumPluginVersions(): ?array
+    {
+        if ($this->altumPluginVersionsCache !== null) {
+            return $this->altumPluginVersionsCache;
+        }
+
+        try {
+            $response = Http::timeout(5)->get('https://dev.altumcode.com/plugins-versions');
+        } catch (\Exception $e) {
+            Log::warning('Uptelligence: AltumCode plugin versions fetch failed', [
+                'error' => $e->getMessage(),
+            ]);
+
+            return null;
+        }
+
+        if (! $response->successful()) {
+            Log::warning('Uptelligence: AltumCode plugin versions request failed', [
+                'status' => $response->status(),
+            ]);
+
+            return null;
+        }
+
+        $this->altumPluginVersionsCache = $response->json() ?? [];
+
+        return $this->altumPluginVersionsCache;
+    }
+
     /**
      * Skip check for vendors that don't support auto-checking.
      */
diff --git a/tests/Unit/AltumCodeCheckerTest.php b/tests/Unit/AltumCodeCheckerTest.php
new file mode 100644
index 0000000..8c92ce0
--- /dev/null
+++ b/tests/Unit/AltumCodeCheckerTest.php
@@ -0,0 +1,364 @@
+<?php
+
+declare(strict_types=1);
+
+use Core\Mod\Uptelligence\Models\Vendor;
+use Core\Mod\Uptelligence\Services\VendorUpdateCheckerService;
+use Illuminate\Support\Facades\Http;
+
+beforeEach(function () {
+    $this->service = new VendorUpdateCheckerService;
+});
+
+// ---------------------------------------------------------------------------
+// isAltumPlatform
+// ---------------------------------------------------------------------------
+
+it('identifies altum platform vendors', function () {
+    $vendor = new Vendor([
+        'slug' => '66analytics',
+        'plugin_platform' => Vendor::PLATFORM_ALTUM,
+    ]);
+
+    $method = new ReflectionMethod($this->service, 'isAltumPlatform');
+    $method->setAccessible(true);
+
+    expect($method->invoke($this->service, $vendor))->toBeTrue();
+});
+
+it('rejects non-altum platform vendors', function () {
+    $vendor = new Vendor([
+        'slug' => 'some-wp-plugin',
+        'plugin_platform' => Vendor::PLATFORM_WORDPRESS,
+    ]);
+
+    $method = new ReflectionMethod($this->service, 'isAltumPlatform');
+    $method->setAccessible(true);
+
+    expect($method->invoke($this->service, $vendor))->toBeFalse();
+});
+
+it('rejects vendors with no platform set', function () {
+    $vendor = new Vendor([
+        'slug' => 'some-oss',
+        'plugin_platform' => null,
+    ]);
+
+    $method = new ReflectionMethod($this->service, 'isAltumPlatform');
+    $method->setAccessible(true);
+
+    expect($method->invoke($this->service, $vendor))->toBeFalse();
+});
+
+// ---------------------------------------------------------------------------
+// checkAltumProduct
+// ---------------------------------------------------------------------------
+
+it('fetches latest version from altum product info endpoint', function () {
+    Http::fake([
+        'https://66analytics.com/info.php' => Http::response([
+            'latest_release_version' => '42.0.0',
+            'product_name' => '66analytics',
+        ], 200),
+    ]);
+
+    $vendor = new Vendor([
+        'slug' => '66analytics',
+        'name' => '66analytics',
+        'plugin_platform' => Vendor::PLATFORM_ALTUM,
+        'source_type' => Vendor::SOURCE_LICENSED,
+        'current_version' => '41.0.0',
+    ]);
+
+    $method = new ReflectionMethod($this->service, 'checkAltumProduct');
+    $method->setAccessible(true);
+
+    $result = $method->invoke($this->service, $vendor);
+
+    expect($result)
+        ->toBeArray()
+        ->and($result['status'])->toBe('success')
+        ->and($result['latest'])->toBe('42.0.0')
+        ->and($result['has_update'])->toBeTrue()
+        ->and($result['release_info']['source'])->toBe('altum_product');
+});
+
+it('detects no update when product version is current', function () {
+    Http::fake([
+        'https://66biolinks.com/info.php' => Http::response([
+            'latest_release_version' => '39.0.0',
+        ], 200),
+    ]);
+
+    $vendor = new Vendor([
+        'slug' => '66biolinks',
+        'name' => '66biolinks',
+        'plugin_platform' => Vendor::PLATFORM_ALTUM,
+        'source_type' => Vendor::SOURCE_LICENSED,
+        'current_version' => '39.0.0',
+    ]);
+
+    $method = new ReflectionMethod($this->service, 'checkAltumProduct');
+    $method->setAccessible(true);
+
+    $result = $method->invoke($this->service, $vendor);
+
+    expect($result['status'])->toBe('success')
+        ->and($result['has_update'])->toBeFalse()
+        ->and($result['latest'])->toBe('39.0.0');
+});
+
+it('returns error when altum product endpoint fails', function () {
+    Http::fake([
+        'https://66analytics.com/info.php' => Http::response('Server Error', 500),
+    ]);
+
+    $vendor = new Vendor([
+        'slug' => '66analytics',
+        'name' => '66analytics',
+        'plugin_platform' => Vendor::PLATFORM_ALTUM,
+        'source_type' => Vendor::SOURCE_LICENSED,
+        'current_version' => '40.0.0',
+    ]);
+
+    $method = new ReflectionMethod($this->service, 'checkAltumProduct');
+    $method->setAccessible(true);
+
+    $result = $method->invoke($this->service, $vendor);
+
+    expect($result['status'])->toBe('error')
+        ->and($result['message'])->toContain('500');
+});
+
+it('returns error when altum product has no version in response', function () {
+    Http::fake([
+        'https://66pusher.com/info.php' => Http::response([
+            'product_name' => '66pusher',
+            // No latest_release_version key
+        ], 200),
+    ]);
+
+    $vendor = new Vendor([
+        'slug' => '66pusher',
+        'name' => '66pusher',
+        'plugin_platform' => Vendor::PLATFORM_ALTUM,
+        'source_type' => Vendor::SOURCE_LICENSED,
+        'current_version' => '5.0.0',
+    ]);
+
+    $method = new ReflectionMethod($this->service, 'checkAltumProduct');
+    $method->setAccessible(true);
+
+    $result = $method->invoke($this->service, $vendor);
+
+    expect($result['status'])->toBe('error')
+        ->and($result['message'])->toContain('Could not determine latest version');
+});
+
+// ---------------------------------------------------------------------------
+// checkAltumPlugin
+// ---------------------------------------------------------------------------
+
+it('fetches latest version for an altum plugin', function () {
+    Http::fake([
+        'https://dev.altumcode.com/plugins-versions' => Http::response([
+            'affiliate' => ['version' => '2.0.1'],
+            'email-notifications' => ['version' => '3.1.0'],
+        ], 200),
+    ]);
+
+    $vendor = new Vendor([
+        'slug' => 'altum-plugin-affiliate',
+        'name' => 'AltumCode Affiliate Plugin',
+        'plugin_platform' => Vendor::PLATFORM_ALTUM,
+        'source_type' => Vendor::SOURCE_PLUGIN,
+        'current_version' => '1.5.0',
+    ]);
+
+    $method = new ReflectionMethod($this->service, 'checkAltumPlugin');
+    $method->setAccessible(true);
+
+    $result = $method->invoke($this->service, $vendor);
+
+    expect($result['status'])->toBe('success')
+        ->and($result['latest'])->toBe('2.0.1')
+        ->and($result['has_update'])->toBeTrue()
+        ->and($result['release_info']['source'])->toBe('altum_plugin')
+        ->and($result['release_info']['plugin_id'])->toBe('affiliate');
+});
+
+it('returns error when plugin is not found in altum registry', function () {
+    Http::fake([
+        'https://dev.altumcode.com/plugins-versions' => Http::response([
+            'affiliate' => ['version' => '2.0.1'],
+        ], 200),
+    ]);
+
+    $vendor = new Vendor([
+        'slug' => 'altum-plugin-nonexistent',
+        'name' => 'Nonexistent Plugin',
+        'plugin_platform' => Vendor::PLATFORM_ALTUM,
+        'source_type' => Vendor::SOURCE_PLUGIN,
+        'current_version' => '1.0.0',
+    ]);
+
+    $method = new ReflectionMethod($this->service, 'checkAltumPlugin');
+    $method->setAccessible(true);
+
+    $result = $method->invoke($this->service, $vendor);
+
+    expect($result['status'])->toBe('error')
+        ->and($result['message'])->toContain('nonexistent')
+        ->and($result['message'])->toContain('not found');
+});
+
+it('returns error when plugin versions endpoint fails', function () {
+    Http::fake([
+        'https://dev.altumcode.com/plugins-versions' => Http::response('Bad Gateway', 502),
+    ]);
+
+    $vendor = new Vendor([
+        'slug' => 'altum-plugin-affiliate',
+        'name' => 'AltumCode Affiliate Plugin',
+        'plugin_platform' => Vendor::PLATFORM_ALTUM,
+        'source_type' => Vendor::SOURCE_PLUGIN,
+        'current_version' => '1.0.0',
+    ]);
+
+    $method = new ReflectionMethod($this->service, 'checkAltumPlugin');
+    $method->setAccessible(true);
+
+    $result = $method->invoke($this->service, $vendor);
+
+    expect($result['status'])->toBe('error')
+        ->and($result['message'])->toContain('Failed to fetch');
+});
+
+// ---------------------------------------------------------------------------
+// In-memory cache
+// ---------------------------------------------------------------------------
+
+it('caches plugin versions across multiple calls', function () {
+    Http::fake([
+        'https://dev.altumcode.com/plugins-versions' => Http::response([
+            'affiliate' => ['version' => '2.0.1'],
+            'email-notifications' => ['version' => '3.1.0'],
+        ], 200),
+    ]);
+
+    $method = new ReflectionMethod($this->service, 'getAltumPluginVersions');
+    $method->setAccessible(true);
+
+    // First call — should hit the HTTP endpoint
+    $first = $method->invoke($this->service);
+    expect($first)->toBeArray()->toHaveKey('affiliate');
+
+    // Second call — should use cache (no additional HTTP request)
+    $second = $method->invoke($this->service);
+    expect($second)->toBe($first);
+
+    // Verify HTTP was only called once
+    Http::assertSentCount(1);
+});
+
+// ---------------------------------------------------------------------------
+// Match routing via checkVendor (integration-level)
+// ---------------------------------------------------------------------------
+
+it('routes altum licensed vendor through checkAltumProduct', function () {
+    Http::fake([
+        'https://66analytics.com/info.php' => Http::response([
+            'latest_release_version' => '42.0.0',
+        ], 200),
+    ]);
+
+    $vendor = Mockery::mock(Vendor::class)->makePartial();
+    $vendor->shouldReceive('getAttribute')->with('slug')->andReturn('66analytics');
+    $vendor->shouldReceive('getAttribute')->with('name')->andReturn('66analytics');
+    $vendor->shouldReceive('getAttribute')->with('plugin_platform')->andReturn(Vendor::PLATFORM_ALTUM);
+    $vendor->shouldReceive('getAttribute')->with('source_type')->andReturn(Vendor::SOURCE_LICENSED);
+    $vendor->shouldReceive('getAttribute')->with('current_version')->andReturn('41.0.0');
+    $vendor->shouldReceive('getAttribute')->with('git_repo_url')->andReturn(null);
+    $vendor->shouldReceive('update')->once()->with(Mockery::on(function ($data) {
+        return array_key_exists('last_checked_at', $data);
+    }));
+    $vendor->shouldReceive('isLicensed')->andReturn(true);
+    $vendor->shouldReceive('isPlugin')->andReturn(false);
+    $vendor->shouldReceive('isOss')->andReturn(false);
+
+    // Use a partial mock of the service to prevent createUpdateTodo from hitting DB
+    $service = Mockery::mock(VendorUpdateCheckerService::class)->makePartial();
+    $service->shouldAllowMockingProtectedMethods();
+    $service->shouldReceive('createUpdateTodo')->once();
+
+    $result = $service->checkVendor($vendor);
+
+    expect($result['status'])->toBe('success')
+        ->and($result['latest'])->toBe('42.0.0')
+        ->and($result['has_update'])->toBeTrue();
+
+    Http::assertSent(function ($request) {
+        return $request->url() === 'https://66analytics.com/info.php';
+    });
+});
+
+it('routes altum plugin vendor through checkAltumPlugin', function () {
+    Http::fake([
+        'https://dev.altumcode.com/plugins-versions' => Http::response([
+            'affiliate' => ['version' => '2.0.1'],
+        ], 200),
+    ]);
+
+    $vendor = Mockery::mock(Vendor::class)->makePartial();
+    $vendor->shouldReceive('getAttribute')->with('slug')->andReturn('altum-plugin-affiliate');
+    $vendor->shouldReceive('getAttribute')->with('name')->andReturn('Affiliate Plugin');
+    $vendor->shouldReceive('getAttribute')->with('plugin_platform')->andReturn(Vendor::PLATFORM_ALTUM);
+    $vendor->shouldReceive('getAttribute')->with('source_type')->andReturn(Vendor::SOURCE_PLUGIN);
+    $vendor->shouldReceive('getAttribute')->with('current_version')->andReturn('1.5.0');
+    $vendor->shouldReceive('getAttribute')->with('git_repo_url')->andReturn(null);
+    $vendor->shouldReceive('update')->once()->with(Mockery::on(function ($data) {
+        return array_key_exists('last_checked_at', $data);
+    }));
+    $vendor->shouldReceive('isLicensed')->andReturn(false);
+    $vendor->shouldReceive('isPlugin')->andReturn(true);
+    $vendor->shouldReceive('isOss')->andReturn(false);
+
+    // Use a partial mock of the service to prevent createUpdateTodo from hitting DB
+    $service = Mockery::mock(VendorUpdateCheckerService::class)->makePartial();
+    $service->shouldAllowMockingProtectedMethods();
+    $service->shouldReceive('createUpdateTodo')->once();
+
+    $result = $service->checkVendor($vendor);
+
+    expect($result['status'])->toBe('success')
+        ->and($result['latest'])->toBe('2.0.1')
+        ->and($result['has_update'])->toBeTrue();
+
+    Http::assertSent(function ($request) {
+        return $request->url() === 'https://dev.altumcode.com/plugins-versions';
+    });
+});
+
+it('normalises version with v prefix from altum product', function () {
+    Http::fake([
+        'https://66socialproof.com/info.php' => Http::response([
+            'latest_release_version' => 'v7.0.0',
+        ], 200),
+    ]);
+
+    $vendor = new Vendor([
+        'slug' => '66socialproof',
+        'name' => '66socialproof',
+        'plugin_platform' => Vendor::PLATFORM_ALTUM,
+        'source_type' => Vendor::SOURCE_LICENSED,
+        'current_version' => '6.0.0',
+    ]);
+
+    $method = new ReflectionMethod($this->service, 'checkAltumProduct');
+    $method->setAccessible(true);
+
+    $result = $method->invoke($this->service, $vendor);
+
+    expect($result['latest'])->toBe('7.0.0')
+        ->and($result['has_update'])->toBeTrue();
+});