mock.
mock APIs fast.

Point Mockzilla at an OpenAPI spec, a folder, a URL, or a .mockz package. Get a realistic, validated, ready-to-call mock API. No code. No signup. No infra.

brew install mockzilla/tap/mockzilla

open source (MIT) 2,200+ real-world specs validated runs anywhere

however you bring it.

Same binary, same engine. Point it at whatever you have.

from a spec

# point at any OpenAPI spec
mockzilla petstore.yml

# or a remote URL
mockzilla https://petstore3.swagger.io/api/v3/openapi.json

Realistic responses generated from the schema. No handwritten fixtures.

from a folder

# one folder, many services
mockzilla ./services/

# or a single service
mockzilla ./pets/

Stripe + Twilio + your own API on one port. Each spec becomes a service with its own prefix.

from a package

# a portable, sharable archive
mockzilla petstore.mockz

# or hosted
mockzilla https://example.com/api.mockz

Pack a service tree once with mockzilla pack and ship it anywhere. Offline, air-gapped, embedded.

.mockz files.

A single archive that holds your specs, static responses, context, and config. One file. One command. Realistic API.

# pack a service folder into a portable bundle
mockzilla pack ./pets

# ship it anywhere
mockzilla pets.mockz --port 3000 --latency 50ms

Tweak how it behaves on the way in:

mockzilla petstore.yml --port 3000 --mount pets/v2 --latency 100ms --errors p5=500,p10=503 --context ./fixtures.yml

what makes it realistic.

schema-aware fakes

Responses generated from your OpenAPI schema with realistic data. Emails, names, UUIDs, dates, currencies.

upstream proxy

Mix real and mocked endpoints. Forward to a real backend, fall back to mocks when it's not there yet.

latency & error injection

Simulate 500s, 503s, slow networks. Test how your client actually behaves when things go sideways.

request validation

Every request is validated against the spec. Catch contract drift before it hits production.

multi-service

Stripe, Twilio, SendGrid, and your own API on one port. Each spec becomes a service with its own mount path.

selective overrides

Auto-generate hundreds of endpoints, hand-craft the few that need custom behavior. Static files or middleware.

from laptop to cloud.

Run it locally for the inner loop. Push to GitHub and get a hosted simulation at api.mockz.io with a unique URL per branch. Same engine. Same .mockz files.

The open-source engine and the cloud share the same DNA. No lock-in, no rewrites.

$ git push origin feature/checkout github action packs your specs mockzilla.org deploys a simulation ready api.mockz.io/gh/you/repo $ curl api.mockz.io/gh/you/repo/pets 200 OK [{"id":"...","name":"Fluffy"}]

try it. right now.