Question 1

How do I create a mock API from a single JSON example?

Accepted Answer

Paste one example response into apimock. It infers the schema — types, nested objects, and arrays with their element shape — then generates as many realistic variant records as you ask for and hands you a json-server db.json, a dependency-free Node server, and an OpenAPI 3.0 stub you can copy or download and run immediately.

Question 2

Will the generated fake data be the same every time?

Accepted Answer

Yes, as long as the seed and the example stay the same. apimock uses a seeded pseudo-random generator (a cyrb53 hash feeding mulberry32), so a given seed reproduces byte-identical records on every run. Change the seed, or press reroll, to get a fresh but equally reproducible set.

Question 3

How does it decide what fake value to put in each field?

Accepted Answer

It reads the example value's type and shape first, then the key name. A value that already looks like a UUID, email, URL, or ISO date is mimicked exactly. Otherwise key-name heuristics kick in: id becomes an integer or uuid, fields ending in _at or containing date become timestamps, name/first/last become person names, price or amount become money, and is/has fields become booleans.

Question 4

Can I run the mock server offline with no dependencies?

Accepted Answer

Yes. Alongside the json-server db.json, apimock emits a standalone server.js that uses only Node's built-in http module — no npm install needed. Save it and run node server.js to serve your mock collection and single-item routes on localhost.

Question 5

Is my example data sent anywhere?

Accepted Answer

No. apimock runs entirely in your browser and a strict Content-Security-Policy sets connect-src to none, so the page cannot make any network request. Your example JSON and everything generated from it never leave your device.

Turn one example response into a whole mock API.

Example response

Inferred schema

Example response

Inferred schema

Generated mock