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Mockaton is an HTTP mock server for simulating APIs. With it, you can test API errors, edge cases, and difficult to reproduce states in general.

Demo (Docker)

This will spin up Mockaton with the sample directory included in this repo mounted on the container.

git clone https://github.com/ericfortis/mockaton.git --depth 1
cd mockaton
make docker

Test it:

curl localhost:2020/api/user

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, so filenames can have dynamic parameters. Also, filenames can have comments, which are anything within parentheses, 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.
• Programmatic API, in which you can delay a route, select a different mock file, such as a 500 error, among other options.

How to scrape your backend APIs?

Mockaton has a Browser Extension that lets you download in bulk all your API responses following Mockaton's filename convention.

Skills

npx skills add ericfortis/mockaton

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.'
  })
}