Scheduling with an API
you can POST to
Trigger bookings via API, automate support scheduling, and let AI agents handle coordination. Full REST API, webhooks, and native MCP support.
Sound familiar?
tickets still need follow-up calls scheduled
A ticket gets closed, but the customer needs a walkthrough. Booking it manually means another email chain and another context switch. Trigger it from your ticketing system via the API instead.
is the test most booking tools fail
They're built for humans clicking buttons, not for scripts and pipelines. Astrocal is API-first: every feature is available over REST, with webhooks and 8 MCP tools for agents.
is what availability becomes when tools sync on a timer
Polling leaves a window for conflicts. Astrocal runs a free/busy check at the moment of each slot request, so a blocked calendar means the slot is simply gone.
Scheduling as infrastructure, not a UI tool
Astrocal is API-first. Every feature is available via REST API with OpenAPI 3.1 documentation. Trigger bookings from scripts, CI/CD pipelines, monitoring alerts, or AI agents. Webhooks notify your stack in real time.
Full REST API
REST endpoints for event types, bookings, availability, and webhooks. OpenAPI 3.1 spec, snake_case JSON, cursor pagination. Build scheduling into anything.
Webhooks on every event
Booking created, cancelled, rescheduled: your stack gets notified instantly. HMAC-signed payloads with automatic retry on failure. Push to Slack, PagerDuty, or your own services.
Native MCP support
The @astrocal/mcp-server npm package gives any MCP-compatible AI agent the ability to check availability and create bookings. Claude, Cursor, or your own agents.
Syncs with your calendar
FreeBusy checks run on every availability request. If a calendar is blocked, that slot disappears. No double-booking, no stale data.
Row-level tenant isolation
PostgreSQL-enforced tenant isolation. Every API call is scoped to your organisation at the database level, not filtered in application code.
Embed or build your own UI
Use the embeddable widget for a quick setup, or skip it entirely and build your own scheduling UI on top of the API. Your choice.
Let AI agents book meetings.
Astrocal ships an MCP server out of the box. Any AI agent that speaks MCP can check availability, create bookings, and manage schedules. No custom integration code required.
- Claude
- GPT-4
- Any MCP-compatible agent
# Install and run the MCP server
npx @astrocal/mcp-server
# Agent calls available via MCP
> list_event_types
> get_available_slots slug="discovery" date="2025-03-20"
> create_booking slug="discovery" start="2025-03-20T10:00:00Z"
name="Jane Doe" email="jane@example.com"Integrated in minutes
See it live. This is a real booking widget.
--astrocal-primary: #2563ebCreate event types via API
Use the REST API to create event types for support calls, maintenance windows, and on-call handoffs. Set durations, availability rules, and buffer times programmatically.
Trigger bookings from your stack
Call the API from your ticketing system, monitoring alerts, or CI/CD pipeline. Or let AI agents book via MCP. Availability is checked in real time against connected calendars.
React to events with webhooks
Every booking event fires a signed webhook. Route it to Slack, PagerDuty, your internal dashboard, or anywhere else. Automatic retries ensure nothing gets lost.
How does Astrocal compare to Calendly?
| Astrocal | Calendly | |
|---|---|---|
| Full REST API (read + write) | ✓ All plans | No endpoint to create bookings |
| Flat pricing, no per-seat fees | ✓ | ✗ Per-seat |
| HMAC-signed webhooks | ✓ | ✓ Paid plans only |
Frequently asked questions
Integrate scheduling into your ops stack
Full API access on every plan. Free to start, no credit card required.