mockaton

name	Mockaton
description	Generates and serves mock HTTP APIs. Use when creating, editing, or reasoning about mock endpoints.
user-invocable	false

Installation (more options ↗)

Mockaton has no dependencies.

npm install -g mockaton

Basic Usage

mockaton --port 2020 my-mocks-dir/

Mockaton will serve the files on the given directory. It's a file-system based router in which filenames can have dynamic parameters and comments. For paraments use square brackets [], and for comments use parentheses (). Comments are handy because this way each route can have different mock file variants. Similarly, each route can have different response status code variants.

Route	Filename	Description
/api/company/123	api/company/[id].GET.200.ts	[id] is a dynamic parameter. .ts, and .js are sent as JSON by default.
/media/avatar.png	media/avatar.png	Statics assets don't need the above extension.
/api/login	api/login(invalid attempt).POST.401.ts	Anything within parenthesis is a comment. They are ignored when routing.
/api/login	api/login(default).GET.200.ts	(default) is a special comment; otherwise, the first mock variant in alphabetical order wins.
/api/login	api/login(locked out user).POST.423.json	.json is allowed too.

Docs

• Configuration: CLI and mockaton.config.js
• API: Programatically, you can delay a route, select a different mock file, etc.

How to create mocks?

Write it to your mocks directory. .ts files are served as JSON by default.

mkdir -p my-mocks-dir/api
echo "export default { name: 'John' }" > my-mocks-dir/api/user.GET.200.ts

Example A: JSON

For JSON responses, use TypeScript (or JS), and export default an Object, Array, or String.

• Route: /api/company/123
• Filename: api/company/[id].GET.200.ts

interface Company {
  name: string
}

export default {
  name: 'Acme, Inc.'
} satisfies Company

Example B: Non-JSON

• Route: /api/company/123
• Filename: api/company/[id].GET.200.xml

<company>
 <name>Acme, Inc.</name>
</company>

Example C: Function Mocks

With a function mock you can do pretty much anything you could do with a normal backend handler. For example, you can handle complex logic, URL parsing, saving to a database, etc.

• Route: /api/company/abc/user/999
• Filename: api/company/[companyId]/user/[userId].GET.200.ts

import { IncomingMessage, OutgoingMessage } from 'node:http'
import { parseSegments } from 'mockaton'

export default async function (req: IncomingMessage, response: OutgoingMessage) {
  const { companyId, userId } = parseSegments(req.url, import.meta.filename)
  const foo = await getFoo()
  return JSON.stringify({
    foo,
    companyId,
    userId,
    name: 'Acme, Inc.'
  })
}