diff --git a/tests/webfinger.test.ts b/tests/webfinger.test.ts
new file mode 100644
index 0000000..34e4e68
--- /dev/null
+++ b/tests/webfinger.test.ts
@@ -0,0 +1,480 @@
+import { describe, it, expect } from 'vitest';
+import { generateWebFingerJRD } from '../src/generators/webfinger.js';
+import type { WebFingerConfig } from '../src/types.js';
+
+describe('generateWebFingerJRD', () => {
+  const testURL = new URL('https://example.com');
+
+  describe('Static Resources', () => {
+    it('returns null for unknown resource', async () => {
+      const config: WebFingerConfig = {
+        resources: [
+          {
+            resource: 'acct:alice@example.com',
+            subject: 'acct:alice@example.com',
+          },
+        ],
+      };
+
+      const result = await generateWebFingerJRD(
+        config,
+        'acct:bob@example.com',
+        undefined,
+        testURL
+      );
+
+      expect(result).toBeNull();
+    });
+
+    it('generates basic JRD for known resource', async () => {
+      const config: WebFingerConfig = {
+        resources: [
+          {
+            resource: 'acct:alice@example.com',
+            subject: 'acct:alice@example.com',
+          },
+        ],
+      };
+
+      const result = await generateWebFingerJRD(
+        config,
+        'acct:alice@example.com',
+        undefined,
+        testURL
+      );
+
+      expect(result).toBeTruthy();
+      const jrd = JSON.parse(result!);
+      expect(jrd.subject).toBe('acct:alice@example.com');
+    });
+
+    it('uses resource as subject when subject not provided', async () => {
+      const config: WebFingerConfig = {
+        resources: [
+          {
+            resource: 'acct:alice@example.com',
+          },
+        ],
+      };
+
+      const result = await generateWebFingerJRD(
+        config,
+        'acct:alice@example.com',
+        undefined,
+        testURL
+      );
+
+      const jrd = JSON.parse(result!);
+      expect(jrd.subject).toBe('acct:alice@example.com');
+    });
+
+    it('includes aliases when provided', async () => {
+      const config: WebFingerConfig = {
+        resources: [
+          {
+            resource: 'acct:alice@example.com',
+            aliases: [
+              'https://example.com/~alice',
+              'https://example.com/users/alice',
+            ],
+          },
+        ],
+      };
+
+      const result = await generateWebFingerJRD(
+        config,
+        'acct:alice@example.com',
+        undefined,
+        testURL
+      );
+
+      const jrd = JSON.parse(result!);
+      expect(jrd.aliases).toEqual([
+        'https://example.com/~alice',
+        'https://example.com/users/alice',
+      ]);
+    });
+
+    it('includes properties when provided', async () => {
+      const config: WebFingerConfig = {
+        resources: [
+          {
+            resource: 'acct:alice@example.com',
+            properties: {
+              'http://schema.org/name': 'Alice Smith',
+              'http://example.com/role': 'Developer',
+            },
+          },
+        ],
+      };
+
+      const result = await generateWebFingerJRD(
+        config,
+        'acct:alice@example.com',
+        undefined,
+        testURL
+      );
+
+      const jrd = JSON.parse(result!);
+      expect(jrd.properties).toEqual({
+        'http://schema.org/name': 'Alice Smith',
+        'http://example.com/role': 'Developer',
+      });
+    });
+
+    it('includes links when provided', async () => {
+      const config: WebFingerConfig = {
+        resources: [
+          {
+            resource: 'acct:alice@example.com',
+            links: [
+              {
+                rel: 'http://webfinger.net/rel/profile-page',
+                href: 'https://example.com/~alice',
+                type: 'text/html',
+              },
+              {
+                rel: 'http://webfinger.net/rel/avatar',
+                href: 'https://example.com/avatars/alice.jpg',
+                type: 'image/jpeg',
+              },
+            ],
+          },
+        ],
+      };
+
+      const result = await generateWebFingerJRD(
+        config,
+        'acct:alice@example.com',
+        undefined,
+        testURL
+      );
+
+      const jrd = JSON.parse(result!);
+      expect(jrd.links).toHaveLength(2);
+      expect(jrd.links[0].rel).toBe('http://webfinger.net/rel/profile-page');
+      expect(jrd.links[0].href).toBe('https://example.com/~alice');
+      expect(jrd.links[1].rel).toBe('http://webfinger.net/rel/avatar');
+    });
+
+    it('filters links by rel when requested', async () => {
+      const config: WebFingerConfig = {
+        resources: [
+          {
+            resource: 'acct:alice@example.com',
+            links: [
+              {
+                rel: 'http://webfinger.net/rel/profile-page',
+                href: 'https://example.com/~alice',
+              },
+              {
+                rel: 'http://webfinger.net/rel/avatar',
+                href: 'https://example.com/avatars/alice.jpg',
+              },
+              {
+                rel: 'http://openid.net/specs/connect/1.0/issuer',
+                href: 'https://auth.example.com',
+              },
+            ],
+          },
+        ],
+      };
+
+      const result = await generateWebFingerJRD(
+        config,
+        'acct:alice@example.com',
+        ['http://webfinger.net/rel/profile-page'],
+        testURL
+      );
+
+      const jrd = JSON.parse(result!);
+      expect(jrd.links).toHaveLength(1);
+      expect(jrd.links[0].rel).toBe('http://webfinger.net/rel/profile-page');
+    });
+
+    it('filters links by multiple rels', async () => {
+      const config: WebFingerConfig = {
+        resources: [
+          {
+            resource: 'acct:alice@example.com',
+            links: [
+              { rel: 'profile', href: 'https://example.com/~alice' },
+              { rel: 'avatar', href: 'https://example.com/avatars/alice.jpg' },
+              { rel: 'blog', href: 'https://blog.example.com/alice' },
+            ],
+          },
+        ],
+      };
+
+      const result = await generateWebFingerJRD(
+        config,
+        'acct:alice@example.com',
+        ['profile', 'blog'],
+        testURL
+      );
+
+      const jrd = JSON.parse(result!);
+      expect(jrd.links).toHaveLength(2);
+      expect(jrd.links[0].rel).toBe('profile');
+      expect(jrd.links[1].rel).toBe('blog');
+    });
+
+    it('includes link titles when provided', async () => {
+      const config: WebFingerConfig = {
+        resources: [
+          {
+            resource: 'acct:alice@example.com',
+            links: [
+              {
+                rel: 'http://webfinger.net/rel/profile-page',
+                href: 'https://example.com/~alice',
+                titles: {
+                  en: 'Alice Smith Profile',
+                  es: 'Perfil de Alice Smith',
+                },
+              },
+            ],
+          },
+        ],
+      };
+
+      const result = await generateWebFingerJRD(
+        config,
+        'acct:alice@example.com',
+        undefined,
+        testURL
+      );
+
+      const jrd = JSON.parse(result!);
+      expect(jrd.links[0].titles).toEqual({
+        en: 'Alice Smith Profile',
+        es: 'Perfil de Alice Smith',
+      });
+    });
+
+    it('generates complete JRD with all fields', async () => {
+      const config: WebFingerConfig = {
+        resources: [
+          {
+            resource: 'acct:alice@example.com',
+            subject: 'acct:alice@example.com',
+            aliases: ['https://example.com/~alice'],
+            properties: {
+              'http://schema.org/name': 'Alice Smith',
+            },
+            links: [
+              {
+                rel: 'http://webfinger.net/rel/profile-page',
+                href: 'https://example.com/~alice',
+                type: 'text/html',
+                titles: { en: 'Profile' },
+              },
+            ],
+          },
+        ],
+      };
+
+      const result = await generateWebFingerJRD(
+        config,
+        'acct:alice@example.com',
+        undefined,
+        testURL
+      );
+
+      const jrd = JSON.parse(result!);
+      expect(jrd.subject).toBe('acct:alice@example.com');
+      expect(jrd.aliases).toEqual(['https://example.com/~alice']);
+      expect(jrd.properties).toEqual({
+        'http://schema.org/name': 'Alice Smith',
+      });
+      expect(jrd.links).toHaveLength(1);
+      expect(jrd.links[0].rel).toBe('http://webfinger.net/rel/profile-page');
+    });
+  });
+
+  describe('HTTP Resource URIs', () => {
+    it('supports https:// resource URIs', async () => {
+      const config: WebFingerConfig = {
+        resources: [
+          {
+            resource: 'https://example.com/user/alice',
+            links: [
+              {
+                rel: 'http://webfinger.net/rel/profile-page',
+                href: 'https://example.com/user/alice',
+              },
+            ],
+          },
+        ],
+      };
+
+      const result = await generateWebFingerJRD(
+        config,
+        'https://example.com/user/alice',
+        undefined,
+        testURL
+      );
+
+      expect(result).toBeTruthy();
+      const jrd = JSON.parse(result!);
+      expect(jrd.subject).toBe('https://example.com/user/alice');
+    });
+  });
+
+  describe('ActivityPub / Fediverse', () => {
+    it('supports ActivityPub profile discovery', async () => {
+      const config: WebFingerConfig = {
+        resources: [
+          {
+            resource: 'acct:alice@example.com',
+            aliases: ['https://example.com/@alice'],
+            links: [
+              {
+                rel: 'self',
+                type: 'application/activity+json',
+                href: 'https://example.com/users/alice',
+              },
+              {
+                rel: 'http://webfinger.net/rel/profile-page',
+                type: 'text/html',
+                href: 'https://example.com/@alice',
+              },
+            ],
+          },
+        ],
+      };
+
+      const result = await generateWebFingerJRD(
+        config,
+        'acct:alice@example.com',
+        undefined,
+        testURL
+      );
+
+      const jrd = JSON.parse(result!);
+      expect(jrd.links).toHaveLength(2);
+      expect(jrd.links[0].type).toBe('application/activity+json');
+      expect(jrd.links[0].rel).toBe('self');
+    });
+  });
+
+  describe('OpenID Connect', () => {
+    it('supports OpenID Connect issuer discovery', async () => {
+      const config: WebFingerConfig = {
+        resources: [
+          {
+            resource: 'acct:alice@example.com',
+            links: [
+              {
+                rel: 'http://openid.net/specs/connect/1.0/issuer',
+                href: 'https://auth.example.com',
+              },
+            ],
+          },
+        ],
+      };
+
+      const result = await generateWebFingerJRD(
+        config,
+        'acct:alice@example.com',
+        ['http://openid.net/specs/connect/1.0/issuer'],
+        testURL
+      );
+
+      const jrd = JSON.parse(result!);
+      expect(jrd.links).toHaveLength(1);
+      expect(jrd.links[0].rel).toBe(
+        'http://openid.net/specs/connect/1.0/issuer'
+      );
+      expect(jrd.links[0].href).toBe('https://auth.example.com');
+    });
+  });
+
+  describe('Edge Cases', () => {
+    it('returns valid JSON for resource with no links', async () => {
+      const config: WebFingerConfig = {
+        resources: [
+          {
+            resource: 'acct:alice@example.com',
+          },
+        ],
+      };
+
+      const result = await generateWebFingerJRD(
+        config,
+        'acct:alice@example.com',
+        undefined,
+        testURL
+      );
+
+      const jrd = JSON.parse(result!);
+      expect(jrd.subject).toBe('acct:alice@example.com');
+      expect(jrd.links).toBeUndefined();
+    });
+
+    it('omits empty aliases array', async () => {
+      const config: WebFingerConfig = {
+        resources: [
+          {
+            resource: 'acct:alice@example.com',
+            aliases: [],
+          },
+        ],
+      };
+
+      const result = await generateWebFingerJRD(
+        config,
+        'acct:alice@example.com',
+        undefined,
+        testURL
+      );
+
+      const jrd = JSON.parse(result!);
+      expect(jrd.aliases).toBeUndefined();
+    });
+
+    it('omits empty properties object', async () => {
+      const config: WebFingerConfig = {
+        resources: [
+          {
+            resource: 'acct:alice@example.com',
+            properties: {},
+          },
+        ],
+      };
+
+      const result = await generateWebFingerJRD(
+        config,
+        'acct:alice@example.com',
+        undefined,
+        testURL
+      );
+
+      const jrd = JSON.parse(result!);
+      expect(jrd.properties).toBeUndefined();
+    });
+
+    it('returns null when all links filtered out by rel', async () => {
+      const config: WebFingerConfig = {
+        resources: [
+          {
+            resource: 'acct:alice@example.com',
+            links: [
+              { rel: 'profile', href: 'https://example.com/~alice' },
+            ],
+          },
+        ],
+      };
+
+      const result = await generateWebFingerJRD(
+        config,
+        'acct:alice@example.com',
+        ['avatar'], // Requesting rel that doesn't exist
+        testURL
+      );
+
+      const jrd = JSON.parse(result!);
+      expect(jrd.links).toBeUndefined();
+    });
+  });
+});