The Booking API for Developers — one REST API, any booking vertical. Build complete management apps, not just widgets.
Create a real booking on our shared sandbox. No API key needed:
Returns a confirmed booking with UUID. The sandbox business (availengine-sandbox) is fully functional with every public endpoint.
Every week, developers ask: "Is there a booking API I can use where I control the frontend?" Existing solutions either have crippled APIs (Calendly can't create events), require self-hosting (Cal.com), or cost $500+/mo (Nylas).
AvailEngine is the booking API developers actually want.
Smart slot calculation with resource assignment, buffer times, capacity management, and service-based duration filtering.
Resources, services, customers, bookings, waitlist, audit logs, stats. Complete business operations, not just booking widgets.
Deposits, authorization holds, no-show captures. Stripe Connect for direct payouts. Built into every booking at the API level.
booking.created, confirmed, completed, deposit.paid, no_show — HMAC-signed payloads with exponential backoff retry.
Scoped API keys, per-key rate limiting, idempotency on all writes, cursor pagination. Built for developers who build.
Every business fully isolated with Row-Level Security. One developer manages many tenants. No competitor does this cleanly.
Drop in Claude Code skills, Cursor rules, or MCP config. Your AI builds the UI; AvailEngine handles the backend.
Two-way sync. Bookings appear in Google Calendar; calendar events block availability. Opt-in, zero overhead.
| Free | Starter | Growth | Scale | |
|---|---|---|---|---|
| Price | €0/mo | €9.99/mo | €29.99/mo | €129/mo |
| Businesses | 1 | 5 | 25 | Unlimited |
| Bookings/mo | 50 | 500 | 25,000 | Unlimited |
| API keys | 3/business | 10/business | 20/business | Unlimited |
| Webhooks | 1 endpoint | 3 endpoints | 10 endpoints | Unlimited |
| Stripe deposits | ✓ | ✓ | ✓ | ✓ |
| Google Calendar | — | — | 1 connection | Unlimited |
| Dynamic booking | — | — | — | ✓ |
See how AvailEngine stacks up against the alternatives:
15 tables, two sittings, real-time floor plan. Open-source Express demo on GitHub →
Live occupancy counter showing 50-spot capacity with real-time booking. 20 lines of integration code.
6 therapists, 12 services, qualification filtering by resource. Running daily in Glyfada.
55 MCP tools for any AI coding agent — Claude Code, Cursor, Windsurf, Cline. Build booking UIs from prompts.
AvailEngine works with Claude Code, Cursor, Windsurf, and any AI coding agent. Drop in our agent skill and your AI becomes an AvailEngine expert — building complete booking UIs from natural language prompts.
# Check availability in one call
curl "https://api.availengine.com/v1/availability/{business_id}?date=2026-07-22&capacity=2"
# Create a booking
curl -X POST https://api.availengine.com/v1/bookings/ \
-H "Authorization: Bearer ***" \
-H "Content-Type: application/json" \
-d '{"business_id":"...","first_name":"Jane","last_name":"Doe",
"booking_date":"2026-07-22","start_time":"14:00","capacity":1}'
# List all bookings (staff view)
curl https://api.availengine.com/v1/manage/bookings?business_id=... \
-H "Authorization: Bearer ***"
Start free. One sandbox business. No credit card. Production when you're ready.
Get Started in 5 Minutes → Browse the API →