diff --git a/src/SimpleRestServer.spec.ts b/src/SimpleRestServer.spec.ts
new file mode 100644
index 0000000..35fb340
--- /dev/null
+++ b/src/SimpleRestServer.spec.ts
@@ -0,0 +1,263 @@
+import { SimpleRestServer } from './SimpleRestServer.ts';
+
+describe('SimpleRestServer', () => {
+    describe('getAll', () => {
+        it('should return list results according to the request parameters', async () => {
+            const data = {
+                posts: [
+                    {
+                        id: 1,
+                        title: 'bazingaaa',
+                    },
+                    {
+                        id: 2,
+                        title: 'bazinga',
+                    },
+                    {
+                        id: 3,
+                        title: 'nope',
+                    },
+                ],
+            };
+
+            const server = new SimpleRestServer({
+                baseUrl: 'http://localhost:4000',
+                data,
+            });
+
+            const response = await server.handleRequest({
+                url: 'http://localhost:4000/posts',
+                method: 'GET',
+                params: {
+                    filter: { q: 'bazin' },
+                    range: [0, 1],
+                    sort: 'title',
+                },
+                requestBody: undefined,
+            });
+
+            expect(response).toEqual(
+                expect.objectContaining({
+                    status: 200,
+                    body: [
+                        {
+                            id: 2,
+                            title: 'bazinga',
+                        },
+                        {
+                            id: 1,
+                            title: 'bazingaaa',
+                        },
+                    ],
+                }),
+            );
+        });
+    });
+    describe('getOne', () => {
+        it('should correctly get records with a numeric identifier', async () => {
+            const data = {
+                posts: [
+                    {
+                        id: 1,
+                        title: 'test',
+                    },
+                ],
+            };
+
+            const server = new SimpleRestServer({
+                baseUrl: 'http://localhost:4000',
+                data,
+            });
+
+            const response = await server.handleRequest({
+                url: 'http://localhost:4000/posts/1',
+                method: 'GET',
+                params: {},
+                requestBody: undefined,
+            });
+
+            expect(response).toEqual(
+                expect.objectContaining({
+                    status: 200,
+                    body: {
+                        id: 1,
+                        title: 'test',
+                    },
+                }),
+            );
+        });
+        it('should correctly get records with a string identifier', async () => {
+            const data = {
+                posts: [
+                    {
+                        id: 'bazinga',
+                        title: 'test',
+                    },
+                ],
+            };
+
+            const server = new SimpleRestServer({
+                baseUrl: 'http://localhost:4000',
+                data,
+            });
+
+            const response = await server.handleRequest({
+                url: 'http://localhost:4000/posts/bazinga',
+                method: 'GET',
+                params: {},
+                requestBody: undefined,
+            });
+
+            expect(response).toEqual(
+                expect.objectContaining({
+                    status: 200,
+                    body: {
+                        id: 'bazinga',
+                        title: 'test',
+                    },
+                }),
+            );
+        });
+    });
+    describe('update', () => {
+        it('should correctly update records with a numeric identifier', async () => {
+            const data = {
+                posts: [
+                    {
+                        id: 1,
+                        title: 'test',
+                    },
+                ],
+            };
+
+            const server = new SimpleRestServer({
+                baseUrl: 'http://localhost:4000',
+                data,
+            });
+
+            const response = await server.handleRequest({
+                url: 'http://localhost:4000/posts/1',
+                method: 'PUT',
+                params: {},
+                requestBody: {
+                    id: 1,
+                    title: 'test42',
+                },
+            });
+
+            expect(response).toEqual(
+                expect.objectContaining({
+                    status: 200,
+                    body: {
+                        id: 1,
+                        title: 'test42',
+                    },
+                }),
+            );
+        });
+        it('should correctly update records with a string identifier', async () => {
+            const data = {
+                posts: [
+                    {
+                        id: 'bazinga',
+                        title: 'test',
+                    },
+                ],
+            };
+
+            const server = new SimpleRestServer({
+                baseUrl: 'http://localhost:4000',
+                data,
+            });
+
+            const response = await server.handleRequest({
+                url: 'http://localhost:4000/posts/bazinga',
+                method: 'PUT',
+                params: {},
+                requestBody: {
+                    id: 'bazinga',
+                    title: 'test42',
+                },
+            });
+
+            expect(response).toEqual(
+                expect.objectContaining({
+                    status: 200,
+                    body: {
+                        id: 'bazinga',
+                        title: 'test42',
+                    },
+                }),
+            );
+        });
+    });
+    describe('delete', () => {
+        it('should correctly delete records with a numeric identifier', async () => {
+            const data = {
+                posts: [
+                    {
+                        id: 1,
+                        title: 'test',
+                    },
+                ],
+            };
+
+            const server = new SimpleRestServer({
+                baseUrl: 'http://localhost:4000',
+                data,
+            });
+
+            const response = await server.handleRequest({
+                url: 'http://localhost:4000/posts/1',
+                method: 'DELETE',
+                params: {},
+                requestBody: undefined,
+            });
+
+            expect(response).toEqual(
+                expect.objectContaining({
+                    status: 200,
+                    body: {
+                        id: 1,
+                        title: 'test',
+                    },
+                }),
+            );
+        });
+        it('should correctly delete records with a string identifier', async () => {
+            const data = {
+                posts: [
+                    {
+                        id: 'bazinga',
+                        title: 'test',
+                    },
+                ],
+            };
+
+            const server = new SimpleRestServer({
+                baseUrl: 'http://localhost:4000',
+                data,
+            });
+
+            const response = await server.handleRequest({
+                url: 'http://localhost:4000/posts/bazinga',
+                method: 'DELETE',
+                params: {},
+                requestBody: {
+                    id: 'bazinga',
+                    title: 'test',
+                },
+            });
+
+            expect(response).toEqual(
+                expect.objectContaining({
+                    status: 200,
+                    body: {
+                        id: 'bazinga',
+                        title: 'test',
+                    },
+                }),
+            );
+        });
+    });
+});
diff --git a/src/SimpleRestServer.ts b/src/SimpleRestServer.ts
index 017c51b..9cd49ae 100644
--- a/src/SimpleRestServer.ts
+++ b/src/SimpleRestServer.ts
@@ -54,7 +54,9 @@ export class SimpleRestServer implements APIServer {
         }
 
         const matches = normalizedRequest.url?.match(
-            new RegExp(`^${this.baseUrl}\\/([^\\/?]+)(\\/(\\w))?(\\?.*)?$`),
+            new RegExp(
+                `^${this.baseUrl}\\/([^\\/?]+)(\\/(\\w+|\\d+))?(\\?.*)?$`,
+            ),
         );
         if (matches) {
             const name = matches[1];
@@ -178,7 +180,9 @@ export class SimpleRestServer implements APIServer {
 
         // handle collections
         const matches = context.url?.match(
-            new RegExp(`^${this.baseUrl}\\/([^\\/?]+)(\\/(\\w))?(\\?.*)?$`),
+            new RegExp(
+                `^${this.baseUrl}\\/([^\\/?]+)(\\/(\\w+|\\d+))?(\\?.*)?$`,
+            ),
         );
         if (!matches) {
             return { status: 404, headers: {} };
@@ -259,7 +263,7 @@ export class SimpleRestServer implements APIServer {
             if (!this.database.getCollection(name)) {
                 return { status: 404, headers: {} };
             }
-            const id = Number.parseInt(matches[3]);
+            const id = matches[3];
             if (context.method === 'GET') {
                 try {
                     return {