@@ -0,0 +1,113 @@
+import { beforeEach, describe, expect, it, vi } from 'vitest';
+import { NextRequest } from 'next/server';
+import { GET } from './route';
+
+vi.mock('@/lib/github', () => ({
+  fetchGitHubContributions: vi.fn(),
+}));
+
+vi.mock('@/lib/calculate', () => ({
+  calculateStreak: vi.fn(),
+}));
+
+vi.mock('@/lib/logger', () => ({
+  logger: {
+    error: vi.fn(),
+  },
+}));
+
+import { fetchGitHubContributions } from '@/lib/github';
+import { calculateStreak } from '@/lib/calculate';
+import { logger } from '@/lib/logger';
+
+describe('OG Route Error Resilience', () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+
+    vi.mocked(fetchGitHubContributions).mockResolvedValue({} as never);
+
+    vi.mocked(calculateStreak).mockReturnValue({
+      totalContributions: 100,
+      longestStreak: 10,
+      currentStreak: 5,
+      todayDate: '2026-07-18',
+    });
+  });
+
+  it('returns a valid image response when GitHub contribution fetching throws an exception', async () => {
+    vi.mocked(fetchGitHubContributions).mockRejectedValueOnce(
+      new Error('Unexpected GitHub service failure')
+    );
+
+    const request = new NextRequest('http://localhost:3000/api/og?user=testuser');
+
+    const response = await GET(request);
+
+    expect(response).toBeDefined();
+    expect(response.status).toBe(200);
+  });
+
+  it('logs the exception when contribution fetching fails', async () => {
+    const error = new Error('Database connectivity failure');
+
+    vi.mocked(fetchGitHubContributions).mockRejectedValueOnce(error);
+
+    const request = new NextRequest('http://localhost:3000/api/og?user=testuser');
+
+    await GET(request);
+
+    expect(logger.error).toHaveBeenCalledWith(
+      'Stats fetch failed',
+      expect.objectContaining({
+        source: 'OG',
+        error,
+      })
+    );
+  });
+
+  it('uses fallback values when contribution fetching fails instead of crashing', async () => {
+    vi.mocked(fetchGitHubContributions).mockRejectedValueOnce(new Error('Service unavailable'));
+
+    const request = new NextRequest('http://localhost:3000/api/og?user=testuser');
+
+    const response = await GET(request);
+
+    expect(response.status).toBe(200);
+    expect(calculateStreak).not.toHaveBeenCalled();
+  });
+
+  it('recovers from malformed contribution data when streak calculation throws', async () => {
+    vi.mocked(fetchGitHubContributions).mockResolvedValueOnce({
+      calendar: {},
+    } as never);
+
+    vi.mocked(calculateStreak).mockImplementationOnce(() => {
+      throw new Error('Invalid contribution data');
+    });
+
+    const request = new NextRequest('http://localhost:3000/api/og?user=testuser');
+
+    const response = await GET(request);
+
+    expect(response).toBeDefined();
+    expect(response.status).toBe(200);
+    expect(logger.error).toHaveBeenCalled();
+  });
+
+  it('continues serving subsequent requests after an earlier request fails', async () => {
+    vi.mocked(fetchGitHubContributions)
+      .mockRejectedValueOnce(new Error('Temporary GitHub failure'))
+      .mockResolvedValueOnce({} as never);
+
+    const failedRequest = new NextRequest('http://localhost:3000/api/og?user=failinguser');
+
+    const recoveredRequest = new NextRequest('http://localhost:3000/api/og?user=recovereduser');
+
+    const firstResponse = await GET(failedRequest);
+    const secondResponse = await GET(recoveredRequest);
+
+    expect(firstResponse.status).toBe(200);
+    expect(secondResponse.status).toBe(200);
+    expect(fetchGitHubContributions).toHaveBeenCalledTimes(2);
+  });
+});