API mock server for local development

If you want an API mock server for local development, here are a few solid options depending on what you need:

Quick, lightweight options

• json-server
  Great if you have a JSON file and want a REST API fast.

  • Easy to set up
  • Supports CRUD
  • Good for frontend dev

• Mockoon

  • GUI-based mock API tool
  • Very fast to create endpoints
  • Can run locally or as a desktop app

• WireMock

  • Better for more advanced stubbing
  • Useful if you need request matching, delays, faults, etc.

If you’re using an OpenAPI spec

• Prism

  • Mocks APIs directly from OpenAPI/Swagger definitions
  • Good for spec-first workflows

• Stoplight Mock Server

  • Also OpenAPI-based
  • Nice for collaborative API design

If you want to implement your own

A simple local mock server can be built with:

• Node.js + Express
• FastAPI (Python)
• Flask (Python)

Example with Express:

import express from "express";

const app = express();
app.use(express.json());

app.get("/api/users", (req, res) => {
  res.json([
    { id: 1, name: "Alice" },
    { id: 2, name: "Bob" }
  ]);
});

app.post("/api/login", (req, res) => {
  res.json({ token: "mock-token-123" });
});

app.listen(3001, () => {
  console.log("Mock API running on http://localhost:3001");
});

Recommendation

• Frontend-only mock data: json-server or Mockoon
• OpenAPI-driven: Prism
• Advanced API behavior: WireMock
• Custom logic: Express or FastAPI

If you want, I can help you set up a mock server in Node.js, Python, or Docker right now.