Form backend that routes: one tool per Postbag API operation, plus quickstart and explain.
dev.postbag/mcp (MCP)
The Model Context Protocol (MCP) server dev.postbag/mcp is a form backend that routes Postbag API operations through one tool per operation. It also provides quickstart and explain capabilities. The project is presented with npm packages for postbag, @postbag/sdk, and @postbag/mcp, and is licensed under AGPL-3.0.
🛠️ Key Features
One MCP tool per Postbag API operation
Quickstart
Explain
🚀 Use Cases
Integrating Postbag form backend operations via MCP tools
Getting up and running using the included quickstart
Understanding behavior or usage via the explain output
⚡ Developer Benefits
Aligns MCP tool granularity with Postbag API operations
Includes related packages: postbag CLI and @postbag/sdk
Distributed as @postbag/mcp for TypeScript-focused stacks
⚠️ Limitations
Only described at the routing/tooling level; specific Postbag operations and tool interfaces are not provided in the source excerpt
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.
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.
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.
Install
Configuration
Environment variables
POSTBAG_API_KEYrequiredsecret
A Postbag API key (pb_live_… or pb_test_…). Mint one at https://postbag.dev/app or with `postbag login`.
POSTBAG_API_URLdefault https://postbag.dev
Base URL of the Postbag API. Defaults to https://postbag.dev — set this only for a self-hosted instance.
