lacspace-mock
Local mock REST/GraphQL from JSON or OpenAPI.
npx lacspace-mock --db db.jsonEverything, in one command
Frontend teams shouldn't have to wait for a backend to exist. lacspace-mock reads a db.json and instantly serves REST CRUD for every collection, answers custom routes described in a small JSON config (templated with path params, request-body fields and a seeded faker), and resolves a pragmatic GraphQL subset — all on node:http with no runtime dependencies. Because the same engine is an importable, port-free library, it doubles as a test fixture: construct a request, assert the response, no sockets. Latency and error-rate knobs let you rehearse loading states and failure handling before you ever hit a real server.
What's inside
Auto REST CRUD
Every JSON collection becomes GET/POST/PUT/PATCH/DELETE with proper status codes and headers.
Rich list queries
Pagination, multi-key sort, field filters, _gte/_lte/_ne/_like operators and full-text q.
Templated custom routes
{{params}}, {{query}}, {{body}}, {{repeat n}} and a seeded faker ({{fake.email}}, {{fake.uuid}}…).
Network simulation
Global/per-route delay (fixed or jitter) and an --error-rate chaos switch for random 500s.
Minimal GraphQL
One POST /graphql resolves collection queries with id/limit args and nested field selection.
Library + CLI
A pure, port-free createEngine().handle() makes it unit-testable and embeddable.
Private by default
Binds to 127.0.0.1, CORS on, --write to persist, zero deps, no telemetry.
Mock from OpenAPI 3
Generate routes + example responses from any spec's component schemas.
Request validation
Reject malformed bodies/params with a 400 + details (per-route or per-collection).
Chaos status pools
Fail a % of responses with any statuses you choose (429,503,…), not just 500.
Record & replay proxy
Forward unknown routes to a real upstream, capture responses, replay them offline.
Stateful CRUD + reset
Mutations persist for the session; reset() snaps the db back for clean test runs.
Copy, paste, done
Real commands and snippets — from a one-liner to the typed library.
npx lacspace-mock --db db.jsonCRUD for every collection at http://127.0.0.1:4000.
curl 'localhost:4000/users?role=admin&_sort=age&_order=desc&_limit=10'operators, q, and X-Total-Count header included.
npx lacspace-mock --config mock.config.jsontemplated routes with {{params}}, {{body}}, {{fake.*}}, {{repeat}}.
npx lacspace-mock --db db.json --delay 50-400 --error-rate 0.1jittered latency + 10% random 500s.
curl -X POST localhost:4000/graphql -d '{"query":"{ users(id:1){ id name } }"}'pragmatic subset: id/limit args, nested selection.
npx lacspace-mock --openapi openapi.jsonOne route per operation, example bodies from your schemas.
npx lacspace-mock db.json --error-rate 0.2 --error-statuses 429,50320% of responses fail with a 429 or 503.
npx lacspace-mock --db db.json --proxy https://api.example.com --record --recordings tape.jsonRe-run with --replay to serve the cassette with no network.
What people build with it
✓ Prototype a UI before the backend exists
✓ Deterministic API fixtures for integration tests
✓ Rehearse loading/error states with latency + chaos
✓ Local contract stubs for a third-party API
Run lacspace-mock today
Free, open-source, no API keys. It's a CLI and a typed library.
npx lacspace-mock --db db.json