Build with Postillion.
Everything you need to provision durable inboxes, route and sign mail, configure authorization, and operate agent mail at scale.
Documentation sections
Quickstart
From API key to a sent message in three calls. Install the SDK, create an inbox, send and receive.
Inboxes & lifecycle
Create, archive, and reactivate durable inboxes. Understand canonical addresses, aliases, and health.
Authorization
Product-shaped controls over communication, sender identity, and visibility. Explain & simulate decisions.
MCP & tools
Point your agent at the hosted MCP server. Inbox, message, thread, and draft tools over one connection.
Domains & DNS
Managed records by default; delegated subdomains for custom domains. DKIM selectors and verification.
Events & webhooks
Subscribe to ReBAC-filtered delivery, policy, auth, and DNS events. Signed, replayable payloads.
Copy these docs as context
Grab the full API surface as Markdown or an
llms.txt bundle and drop it straight into
your agent's context window.
Changelog
RSS →Ask concrete "why allowed / denied?" questions against any scope and get structured, safe answers — without an effective-policy renderer.
Reactivating an archived inbox now rotates its selector instead of reusing old signing material.
Inbox, message, thread, draft, and attachment tools available over OAuth at mcp.postillion.ai.
Receive/send allow-block by address, domain, inbox, or workspace replaces flat lists. Exact-domain matching only.