# Astrocal

> API-first, MCP-native scheduling platform for AI agents and developers.

Astrocal is a hosted scheduling API (there is no self-hosted or on-premise option) with embeddable booking widgets, two-way calendar sync (Google Calendar, Microsoft 365/Outlook, and CalDAV), Stripe payments, webhooks, and a native MCP (Model Context Protocol) server so AI agents can book autonomously. Every plan — including the free tier — has the full REST API (OpenAPI 3.1) and the MCP server. Pricing is flat-rate with no per-seat fees: Free (10 bookings/month, free API key, no credit card) and paid plans from $12/month. Developers integrate via the REST API at `api.astrocal.dev`, the npm packages `@astrocal/widget` and `@astrocal/mcp-server`, and the dashboard at `astrocal.dev`.

## Product

- [About Astrocal — API-First Scheduling](https://www.astrocal.dev/about): Astrocal is the scheduling API built for AI agents and developers. MCP-native, whitelabel, usage-based pricing. Infrastructure for programmatic booking.
- [Booking Software for Small Businesses](https://www.astrocal.dev/booking-software-for-small-businesses): Booking software that runs itself. Set up your services once, share a link or embed a widget, and take bookings and payments without touching code.
- [Booking Widget: Embed Scheduling on Any Website](https://www.astrocal.dev/widget): Add a booking widget to any website with one line of code. DOM-native, fully themeable, real-time availability, Stripe payments, and popup mode.
- [Features: Appointment Scheduling Software](https://www.astrocal.dev/features): Appointment scheduling software with calendar sync, payments, webhooks, whitelabel booking widget, and AI scheduling tools. Free plan, no per-seat fees.
- [Free Booking Software: No Credit Card, Live in 5 Minutes](https://www.astrocal.dev/free-booking-software): Astrocal's free plan includes 10 bookings a month, full API access, calendar sync, and the embeddable widget. No credit card, no time limit.
- [Online Booking System: Free to Start](https://www.astrocal.dev/booking-system): Free online booking system for websites and apps. Full REST API, calendar sync, Stripe payments, and whitelabel embedding. 10 free bookings a month.
- [Scheduling API & Calendar API for Developers](https://www.astrocal.dev/calendar-api): REST scheduling API for availability, bookings, webhooks, and calendar sync. OpenAPI 3.1, cursor pagination, and MCP support. Free API key, no credit card.
- [Scheduling Software: API-First Booking for Any Stack](https://www.astrocal.dev/scheduling-software): Scheduling software and appointment scheduler for any stack. REST API, embeddable booking widget, calendar sync, payments, and AI agent support. Free to start.
- [Support — Get Help with Astrocal](https://www.astrocal.dev/support): Get help with Astrocal. Reach the team with a pre-sales question, billing issue, bug report, or integration help via our contact form.

## Developers & API

- [Booking API: REST Endpoints for Appointment Scheduling](https://www.astrocal.dev/developers/booking-api): A booking API you can build a product on. Create, reschedule, and cancel bookings via REST, with availability, webhooks, and an OpenAPI 3.1 spec.
- [CalDAV Integration](https://www.astrocal.dev/developers/caldav): Connect iCloud, Fastmail, Nextcloud, or any CalDAV calendar to Astrocal for real-time availability and two-way booking sync. Password auth, no OAuth.
- [Google Calendar API for Developers](https://www.astrocal.dev/developers/calendar-api): A free calendar API for availability, bookings, and two-way sync. Connect Google, Outlook, or CalDAV. OpenAPI 3.1, no OAuth plumbing, no credit card.
- [Open-Source SDKs at Astrocal](https://www.astrocal.dev/developers/open-source): Astrocal's SDKs and MCP server are open source. Inspect the code, contribute fixes, and build on a transparent foundation.
- [SDKs & Libraries](https://www.astrocal.dev/developers/sdks): Official Astrocal SDKs for React, vanilla JS, and AI agents via MCP. Drop-in scheduling for any stack.
- [Webhook Events](https://www.astrocal.dev/developers/webhooks): Receive real-time notifications when bookings are created, cancelled, or rescheduled. Signed payloads with automatic retries.

## Use cases

- [AI Agent Scheduling: Let Your AI Book Meetings via MCP](https://www.astrocal.dev/use-cases/ai-agent-scheduling): Connect AI agents to real calendars with Astrocal's MCP server. Autonomous booking, availability checking, and rescheduling, with no human in the loop.
- [Automatic Appointment Reminders](https://www.astrocal.dev/use-cases/appointment-reminders): Reduce no-shows with automated email reminders sent before every appointment. No manual follow-up. Free to start.
- [Group Event Scheduling Software](https://www.astrocal.dev/use-cases/group-events): One time slot, multiple attendees. Run workshops, classes, and webinars with capacity limits and automated registration. Free to start.
- [How to Add Booking to Your Website](https://www.astrocal.dev/use-cases/website-booking-widget): How to add a booking widget to your website. Embed real-time scheduling with a script tag. No iframe, themed to your brand, on WordPress, Webflow, or any site.
- [Round Robin Scheduling for Teams](https://www.astrocal.dev/use-cases/round-robin): Distribute meetings evenly across your team. Clients pick a time and Astrocal assigns the next available member. No per-seat fees.

## Comparisons

- [Astrocal vs Acuity Scheduling in 2026: The Honest Comparison](https://www.astrocal.dev/compare/vs-acuity): The Acuity alternative with a full API on every plan, flat-rate pricing, and native MCP support. See how Astrocal compares to Acuity Scheduling.
- [Astrocal vs Cal.com in 2026: The Honest Comparison](https://www.astrocal.dev/compare/vs-cal-com): The Cal.com alternative you don't have to deploy. Hosted API, flat-rate pricing, and a whitelabel widget. See how Astrocal compares to Cal.com.
- [Astrocal vs Calendly in 2026: The Honest Comparison](https://www.astrocal.dev/compare/vs-calendly): Flat-rate pricing, true white-label, and a full REST API. See how Astrocal compares to Calendly feature by feature.
- [Astrocal vs Doodle in 2026: The Honest Comparison](https://www.astrocal.dev/compare/vs-doodle): The Doodle alternative that confirms the meeting: instant bookings, a full REST API, flat-rate pricing, and native MCP support.
- [Astrocal vs SavvyCal in 2026: The Honest Comparison](https://www.astrocal.dev/compare/vs-savvycal): The SavvyCal alternative built to embed: flat-rate pricing, a full REST API on every plan, and native MCP support. See how Astrocal compares to SavvyCal.
- [Astrocal vs TidyCal in 2026: The Honest Comparison](https://www.astrocal.dev/compare/vs-tidycal): The TidyCal alternative with a full API: flat-rate pricing, whitelabel embedding, and native MCP support. See how Astrocal compares to TidyCal.
- [The Best Calendly Alternative in 2026](https://www.astrocal.dev/compare/calendly-alternative): Looking for a Calendly alternative? Astrocal offers a full REST API, true whitelabel, no per-seat pricing, and native MCP support for AI agents.

## Integrations

- [Google Calendar Booking System: Real-Time Sync](https://www.astrocal.dev/integrations/google-calendar): Turn Google Calendar into a booking system. One-click OAuth, real-time free/busy sync, automatic events with Google Meet links. Free plan included.
- [HubSpot Integration: Sync Bookings to Your CRM](https://www.astrocal.dev/integrations/hubspot): Push Astrocal booking data into HubSpot automatically via webhooks. Create activities, update contacts, and keep your pipeline in sync. No manual entry.
- [Outlook Booking System: Real-Time Microsoft 365 Sync](https://www.astrocal.dev/integrations/outlook): Turn your Outlook calendar into a booking system. One-click Microsoft 365 OAuth, real-time sync, automatic events with Teams links. Free plan included.
- [Salesforce Integration: Sync Bookings to Your CRM](https://www.astrocal.dev/integrations/salesforce): Push Astrocal booking data into Salesforce automatically via webhooks. Create activities, update contacts, and keep your pipeline in sync. No manual entry.
- [WordPress Booking Plugin Alternative: One Script Tag](https://www.astrocal.dev/integrations/wordpress): Skip the WordPress booking plugin. One script tag adds a real-time booking calendar with Stripe payments to any page. No PHP, no database tables.
- [Zapier Integration: Connect Bookings to 8,000+ Apps](https://www.astrocal.dev/integrations/zapier): Connect Astrocal to Zapier via webhooks. Trigger workflows in any of 8,000+ apps when a booking is created, rescheduled, or cancelled. No code required.

## Solutions

- [Booking Software for Freelancers](https://www.astrocal.dev/solutions/freelancers): Share a link, get booked and paid. Calendar sync, Stripe payments, automated reminders, and no per-seat fees. Free to start.
- [Interview Scheduling Software for Recruiters](https://www.astrocal.dev/solutions/recruiters): Let candidates self-schedule interviews across your hiring team. Calendar sync, automated reminders, and no per-seat fees. Free to start.
- [Scheduling Software for Customer Success Teams](https://www.astrocal.dev/solutions/customer-success): Automate onboarding calls, QBRs, and check-ins. Calendar sync, automated reminders, and no per-seat fees. Free to start.
- [Scheduling Software for IT Ops Teams](https://www.astrocal.dev/solutions/it-ops): Trigger bookings via API, automate support scheduling, and let AI agents handle coordination. Full REST API, webhooks, and native MCP support.
- [Scheduling Software for Sales Teams](https://www.astrocal.dev/solutions/sales-teams): Cut response time, book more demos, and stop losing deals to scheduling friction. Free booking links with calendar sync and no per-seat fees.

## Industries

- [Booking Software for Auto Shops & Dealerships](https://www.astrocal.dev/industries/automotive): Let customers book service appointments and test drives online. Calendar sync, automated reminders, Stripe payments, and no per-seat fees.
- [Booking Software for Events & Venues](https://www.astrocal.dev/industries/events-venues): Let guests book your venue, tours, and event slots online. Calendar sync, automated reminders, Stripe payments, and no per-seat fees.
- [Salon Booking System for Beauty Businesses](https://www.astrocal.dev/industries/beauty-wellness): The salon booking system that fills your chairs. One link for every service and stylist, deposits via Stripe, automatic reminders. Free to start.
- [Scheduling Software for Education & Tutoring](https://www.astrocal.dev/industries/education): Let students book office hours, tutoring sessions, and parent meetings online. Calendar sync, automated reminders, and no per-seat fees.
- [Scheduling Software for Financial Advisors & Brokers](https://www.astrocal.dev/industries/financial-services): Let clients book consultations online. Calendar sync, automated reminders, Stripe payments, and no per-seat fees. Free to start.

## Guides

- [AI Scheduling Assistant: How AI Agents Book Meetings in 2026](https://www.astrocal.dev/blog/guides/ai-scheduling-assistant): AI scheduling assistants use MCP and REST APIs to book meetings autonomously. Learn how they work, which tools support them, and how to set one up.
- [Appointment Scheduling Software: Buyer's Guide (2026)](https://www.astrocal.dev/blog/guides/appointment-scheduling-software): How to evaluate appointment scheduling software: pricing models, feature comparison, and which tool fits your business.
- [Best Booking System for Personal Trainers (2026)](https://www.astrocal.dev/blog/guides/fitness-booking-system): How to choose a booking system for your PT business or fitness studio — covering no-shows, session packages, and the five main tools compared.
- [Best Scheduling Tools in 2026: An Honest Comparison](https://www.astrocal.dev/blog/guides/best-scheduling-tools): A detailed comparison of 8 scheduling and booking tools - pricing, API access, embeds, and deposits - to help you pick the right one.
- [Booking System for Coaches, Therapists and Consultants (2026 Guide)](https://www.astrocal.dev/blog/guides/booking-system-for-coaches-and-therapists): How to choose a booking system for one-to-one client work: paid sessions, video links, time zones, and a calendar that protects your energy.
- [Build an AI Booking Agent with MCP: A Step-by-Step Tutorial (2026)](https://www.astrocal.dev/blog/guides/build-ai-booking-agent-mcp): A hands-on tutorial: connect Claude (or any MCP client) to a real calendar and let it check availability and book meetings autonomously.
- [Free Online Booking System: 7 Tools Compared (2026)](https://www.astrocal.dev/blog/guides/free-online-booking-system): Compare the best free online booking systems for websites. Real free-plan limits for Astrocal, Calendly, Cal.com, TidyCal, Setmore, Zoho, and SimplyBook.me.
- [Give Your AI Agent a Real Calendar: Add Booking to a Custom Agent (2026)](https://www.astrocal.dev/blog/guides/ai-agent-calendar-api): Give your own AI agent a real calendar: use the Vercel AI SDK and Astrocal's REST API to check availability and book confirmed meetings via tool calls.
- [How to Reduce Appointment No-Shows: What Actually Works (2026)](https://www.astrocal.dev/blog/guides/how-to-reduce-appointment-no-shows): Deposits, reminders, and cancellation policies - the three things that actually cut no-show rates. A practical guide for service businesses.
- [The Best Salon Booking System: How to Choose & Set Up in 2026](https://www.astrocal.dev/blog/guides/salon-booking-system-guide): A salon owner's guide to choosing the right booking system - deposits, reminders, multi-staff, and no more no-shows.
- [What Is an Online Booking System? The Complete Guide (2026)](https://www.astrocal.dev/blog/guides/what-is-an-online-booking-system): Learn what an online booking system does, who needs one, and how to choose the right tool for your business.

## Documentation

- [Authentication](https://www.astrocal.dev/docs/guides/authentication): How to authenticate with the Astrocal API using API keys.
- [Availability](https://www.astrocal.dev/docs/guides/availability): Configure weekly availability windows and query bookable time slots.
- [Bookings](https://www.astrocal.dev/docs/guides/bookings): Create, cancel, and reschedule bookings via the Astrocal API.
- [Calendars](https://www.astrocal.dev/docs/guides/calendars): Connect Google, Microsoft, and CalDAV calendars for automatic busy-time blocking.
- [Claude Code](https://www.astrocal.dev/docs/guides/mcp-clients/claude-code): Add Astrocal to Claude Code with a single terminal command.
- [Claude Desktop](https://www.astrocal.dev/docs/guides/mcp-clients/claude-desktop): Connect Astrocal to Claude Desktop with the one-click bundle or a config snippet.
- [Conferencing](https://www.astrocal.dev/docs/guides/conferencing): Add Zoom, Google Meet, or Microsoft Teams video links to every booking automatically.
- [Cursor](https://www.astrocal.dev/docs/guides/mcp-clients/cursor): Connect Astrocal to Cursor with one-click install or an MCP config file.
- [Embeddable Widget](https://www.astrocal.dev/docs/guides/widget): Drop-in booking widget for any website with one script tag.
- [Errors](https://www.astrocal.dev/docs/guides/errors): Complete reference of Astrocal API error codes, HTTP statuses, and handling guidance.
- [Event Types](https://www.astrocal.dev/docs/guides/event-types): Create and manage bookable event types with duration, pricing, and booking caps.
- [MCP Integration](https://www.astrocal.dev/docs/guides/mcp-integration): Connect AI agents to Astrocal using the Model Context Protocol.
- [Payments](https://www.astrocal.dev/docs/guides/payments): Collect payments for bookings using Stripe Connect
- [Quickstart](https://www.astrocal.dev/docs/guides/quickstart): Book your first meeting in 5 minutes.
- [Rate Limits](https://www.astrocal.dev/docs/guides/rate-limits): Understand Astrocal's rate limiting, usage quotas, and how to handle 429 responses.
- [React SDK](https://www.astrocal.dev/docs/guides/react): First-class React integration with Provider, hooks, and an embeddable booking widget.
- [Remote Connector (OAuth)](https://www.astrocal.dev/docs/guides/mcp-clients/remote-connector): Add Astrocal as a hosted custom connector with OAuth — no install, no API key.
- [Sandbox Mode](https://www.astrocal.dev/docs/guides/sandbox-mode): Test your integration safely with sandbox mode. No real calendar events, emails, or payments.
- [VS Code](https://www.astrocal.dev/docs/guides/mcp-clients/vscode): Connect Astrocal to VS Code (Copilot agent mode) with one-click install or a config file.
- [Waitlist](https://www.astrocal.dev/docs/guides/waitlist): Let invitees queue for fully-booked slots and get promoted automatically when someone cancels.
- [Webhooks](https://www.astrocal.dev/docs/guides/webhooks): Receive real-time HTTP notifications when booking events occur.
- [Windsurf](https://www.astrocal.dev/docs/guides/mcp-clients/windsurf): Connect Astrocal to Windsurf via its MCP config file.

## API Reference

- [API Reference](https://www.astrocal.dev/docs/api-reference): Complete REST API reference (OpenAPI 3.1)

## Links

- [Website](https://www.astrocal.dev): Astrocal home
- [Pricing](https://www.astrocal.dev/pricing): Plans and limits, free to start
- [npm: @astrocal/widget](https://www.npmjs.com/package/@astrocal/widget): Embeddable booking widget
- [npm: @astrocal/mcp-server](https://www.npmjs.com/package/@astrocal/mcp-server): MCP server for AI agents
- [GitHub](https://github.com/astrocal-dev): Open-source SDKs and MCP server