Agent-native email, end to end.

Key → agent → first send → first reply event. The five-minute path through the REST API, with copy-paste curl and fetch.

Bearer keys, the mk_live_ format, three scopes (send / read / manage), live vs test mode, and rotation. Everything about authenticating a request.

Workspace, agent, message, event, thread, draft, webhook, suppression, reputation — the eight nouns the API is built from, and how they fit together.

Every endpoint, with the exact request and response fields — messages, batch, received, events, webhooks, agents, keys, suppression.

One envelope on every failure — type, code, message, param, request_id. The type → status mapping and the full code list.

List events or tail the live SSE stream. Every event type, the inbound payload, and a reconnect-safe consumer.

Register an endpoint, verify the HMAC signature, handle retries. The push half of the events model, done safely.

REST is available now. The TypeScript/Python SDKs and the MCP server publish at Phase 1 launch — here's the shape they'll take.

Per-tier send caps, single-message payload limits, and the 429 + Retry-After behavior when you exceed them.