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Postbag MCP Server

by Faahim
Developer ToolsLow Risk9.7MCP RegistryLocal
Free

Server data from the Official MCP Registry

Form backend that routes: one tool per Postbag API operation, plus quickstart and explain.

About

Form backend that routes: one tool per Postbag API operation, plus quickstart and explain.

Security Report

9.7
Low Risk9.7Low Risk

Valid MCP server (4 strong, 2 medium validity signals). 1 code issue detected. No known CVEs in dependencies. ⚠️ Package registry links to a different repository than scanned source. Imported from the Official MCP Registry. 2 finding(s) downgraded by scanner intelligence.

21 files analyzed · 2 issues found

Security scores are indicators to help you make informed decisions, not guarantees. Always review permissions before connecting any MCP server.

Permissions Required

This plugin requests these system permissions. Most are normal for its category.

file_system

Check that this permission is expected for this type of plugin.

What You'll Need

Set these up before or after installing:

A Postbag API key (pb_live_… or pb_test_…). Mint one at https://postbag.dev/app or with `postbag login`.Required

Environment variable: POSTBAG_API_KEY

Base URL of the Postbag API. Defaults to https://postbag.dev — set this only for a self-hosted instance.Optional

Environment variable: POSTBAG_API_URL

How to Install

Add this to your MCP configuration file:

{
  "mcpServers": {
    "dev-postbag-mcp": {
      "env": {
        "POSTBAG_API_KEY": "your-postbag-api-key-here",
        "POSTBAG_API_URL": "your-postbag-api-url-here"
      },
      "args": [
        "-y",
        "@postbag/mcp",
        "-y"
      ],
      "command": "npx"
    }
  }
}

Documentation

View on GitHub

From the project's GitHub README.

Postbag

CI npm: postbag npm: @postbag/sdk npm: @postbag/mcp License: AGPL-3.0

A form backend that routes. Point any HTML form at a Postbag endpoint and it lands in your inbox — then goes wherever it should: email, Telegram, a webhook, a partner, your CRM. Built for people who run many sites, and for the AI agents that build them.

<form action="https://api.postbag.dev/s/fm_8f3kq2" method="POST">
  <input name="email" type="email" required>
  <textarea name="message"></textarea>
  <button>Send</button>
</form>

That's the whole integration for one form. Everything else — grouping forty forms into one stream, mapping their different fields onto one shape, sending that shape to a partner between two dates, a daily digest, never losing a submission — is there when you need it and invisible when you don't.

New here (human or AI agent)? Read CLAUDE.md first.

Why it exists

Every website has forms. Every form needs somewhere to go. Formspree and friends solve "somewhere" for one site; they fall over when you have fifteen sites feeding one partner with fifteen slightly different forms. Postbag is the source of truth for what each form collects, what each downstream system receives, and the versioned contract between them.

The one idea

The database makes it correct; events make it fast.

A submission is accepted the instant it is a row. Delivery is a durable outbox that a worker drains with retries. Realtime nudges are an accelerator, never a transport. If every event stream in the system died, every submission would still arrive — late, never lost. (Inherited from the lead pipeline this generalises; see docs/ARCHITECTURE.md.)

Status

Phase 1 — MVP live at postbag.dev (site, docs, dashboard at /app, API at /v1). See PROGRESS.md for the live blueprint and docs/ROADMAP.md for phases.

Documentation

Start at docs/README.md.

License

The server, dashboard, site and domain packages (apps/*, packages/core, packages/db, packages/auth) are licensed under AGPL-3.0. The client packages that run inside your own code — @postbag/sdk, the postbag CLI and @postbag/mcp — are MIT. Rationale in ADR-006.

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Postbag MCP Server - Form backend that routes: one tool per Postbag API | MCP Marketplace