# API Reference

Sistava API reference. Send prompts to your AI employees over REST, MCP, A2A, webhooks, and email. Bearer auth, typed params, copy-paste code.

## Get started

- [API overview](/en/docs/overview) - The Sistava API is a RESTful API at sistava.com for programmatic access to your AI employees — message them, trigger work, and connect external tools and agents.
- [Authentication](/en/docs/authentication) - All requests use a Bearer token. One key works across every programmatic channel.
- [Errors](/en/docs/errors) - Standard HTTP status codes. Bodies include a human-readable message.
- [Rate limits](/en/docs/rate-limits) - Limits are per API key and per IP. Exceeding them returns 429 with a Retry-After: 60 header.

## REST API

- [Send a message](/en/docs/chat) `POST /api/v1/chat` - Send a prompt to an employee and get their response. Same execution pipeline as web chat — same skills, tools, memory, and billing.
- [Health check](/en/docs/health) `GET /api/v1/health` - Returns ok if the service is reachable. Requires authentication.

## Protocols

- [MCP server](/en/docs/mcp) - Connect any MCP client (Claude Desktop, Cursor) to a single endpoint that exposes a chat tool for your employees.
- [Agent-to-Agent (A2A)](/en/docs/a2a) - Let external AI agents discover your employees via an Agent Card and delegate work over JSON-RPC 2.0, synchronously or via SSE streaming.
- [Inbound webhooks](/en/docs/webhooks) `POST /api/webhook/` - POST an event from your systems and an employee picks it up and acts in the background. Fire-and-forget — no response to wait on.
- [Email webhook](/en/docs/email) `POST /api/email/` - An inbound-parse provider (SendGrid, Mailgun, Postmark) or a forwarding rule POSTs parsed mail to this endpoint. The employee processes it and replies via outbound email. Distinct from the hosted Personal Mailbox and the Gmail OAuth tool.