MCP Server coming soon

Email for AI agents — send, receive, and react from any LLM

Give your Claude, OpenAI, or custom agent a real email address. Postkit exposes sending, inbound parsing, and webhook events through an MCP server and a compact REST surface designed for tool use.

Get Started Free Quickstart

Why Postkit for agents

Every feature that makes Postkit reliable for apps makes it essential for autonomous agents.

Idempotent sends

Agents retry. That's by design. An Idempotency-Key header guarantees the same email is never sent twice, even across retry loops.

Signed webhooks

Let agents subscribe to delivery events, bounces, and replies. HMAC-SHA256 signing (Standard Webhooks) means your agent can verify every callback.

Inbound parsing

Give your agent a real inbox. Postkit receives email, parses MIME, stores attachments, and surfaces everything through the REST API.

Predictable rate limits

Standard X-RateLimit and Retry-After headers on every response. Agents can throttle themselves without guessing.

Scoped API keys

Issue sending_access keys that can only send — no domain deletion, no webhook reconfiguration. Least-privilege for autonomous code.

EU data residency

Running agents on EU infrastructure? Your email data stays in the EU too. Hetzner Cloud, Vienna and Frankfurt. No US cloud providers.

MCP Server

Model Context Protocol for email

Install the Postkit MCP server and your Claude agent gets email superpowers — sending, status checks, inbound reading, and template management, all as native tools.

MCP tools

postkit.send_email// Send a transactional email (single or batch)

postkit.get_email// Check delivery status of a sent email

postkit.list_inbound// List received inbound emails

postkit.get_inbound_email// Read a specific inbound email with parsed body and attachments

postkit.create_template// Create a Handlebars email template

postkit.render_template// Preview a template with variables before sending

The MCP server is under active development.

Until it ships, you can use the Postkit REST API directly via OpenAI function calling, LangChain tools, or any HTTP-capable agent framework. See the quickstart.

Works with any LLM

Postkit's REST API is already usable as a tool. Register the endpoints as functions and your agent can send email today.

Claude (MCP)

Once the MCP server ships, add it to your claude_desktop_config.json or Claude Code settings — every Postkit tool appears automatically.

{
  "mcpServers": {
    "postkit": {
      "command": "npx",
      "args": ["-y", "@postkit/mcp"],
      "env": {
        "POSTKIT_API_KEY": "pk_live_..."
      }
    }
  }
}

OpenAI function calling

Define Postkit endpoints as tools in your assistant config. The OpenAPI spec at /openapi.json provides ready-made schemas.

tools: [{
  type: "function",
  function: {
    name: "send_email",
    description: "Send a transactional email via Postkit",
    parameters: {
      type: "object",
      properties: {
        to: { type: "string" },
        subject: { type: "string" },
        html: { type: "string" }
      },
      required: ["to", "subject", "html"]
    }
  }
}]

What agents build with email

Customer support triage

Agent receives inbound emails, classifies intent, drafts a response, and sends it — with a human-in-the-loop approval step.

Autonomous follow-ups

After a user signs up but doesn't activate, the agent checks status and sends a personalized nudge email after 48 hours.

Lead response agents

Inbound lead emails are parsed, enriched via external APIs, and replied to within minutes — not hours.

Monitoring and alerting

Agent monitors infrastructure metrics, composes a human-readable summary, and emails the on-call team when thresholds are breached.

Research and newsletter

Agent gathers sources on a topic, synthesizes a summary, renders it into a template, and sends a curated newsletter.

Ready to give your agent an inbox?

Start with the REST API today. The MCP server is coming soon — sign up and we'll let you know the moment it ships.

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