I usually just return a temporary json object in the function that should be calling the API. eg As long as an API contract has been agreed, should be good. More on amp.reddit.com

$ npx api-nowThen try your mock api like: $ curl http://localhost:3003/users?_page=1&_limit=5

Github repo: https://github.com/ngduc/api-now

Features:

• Default datasets out-of-the-box: todos, users, posts, comments (using faker). Just run $ api-now

• HTTPS support (with key, cert files).

• Can take a .json or .js file.

• GraphQL endpoint to serve faker data: /graphql

• Can serve a static directory (e.g. /dist, /public etc.)

• APIs support pagination (_page, _limit).

• /echo route to respond parameters back as json.

• /file route to serve any file type (including images).

• /login route (POST) to respond with a dummy JWT token (using jsonwebtoken).

• /todos route to return a list of todo items (follow TodoMVC specs).

• /image/random to serve a random image file from a directory.

• /avatar/random to serve a random avatar image.

• /nature/random to serve a random nature image.

More on reddit.com

I started using Mock Service Worker recently: https://mswjs. It runs a Service Worker in the browser that intercepts network requests, and then returns mocked data. It only intercepts requests you have specified. You only need a single flag in your application to say whether the Service Worker should be included. e.g. on Production, exclude it, locally, include it. This is great as all the code relating to your API calls stays the same, and you still see the requsts in the Browser's Network tab. One of your handlers may look like this: rest.post('/login', (req, res, ctx) => { const { username } = req.body if (username === 'simulate-fail-user') { // return an error return res( ctx.status(400), ctx.text('this user does not exist') ) } return res( ctx.json({ username, firstName: 'John' }) ) }) You are telling the Service Worker to intercept any requests to /login, and you can determine what the response should be. Essentially you are also mocking the server code here. You are saying, if the username is 'simular-fail-user', return an error. This allows you to easily test the error paths in your application. Furthermore, this library can also be used when running your test suites, so there is no need to mock your API calls during your unit/integration tests. I originally found out about it from this blog: https://kentcdodds.com/blog/stop-mocking-fetch/ More on reddit.com