Letmepost MCP Server

letmepost.dev

An open-source social media publishing API that fails loudly. One POST /v1/posts across every platform. Stable error codes, the rule that failed, the raw platform body, and a remediation — on every failure. Never an empty { body: {} }. No per-profile tax.

An alternative to: Ayrshare, Postiz, Buffer, Hootsuite, Hypefury.

Website · Docs · Quickstart · Dashboard · API Reference

Supports: Bluesky · LinkedIn · X · Threads · Instagram · Facebook · Pinterest · YouTube

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The four guarantees on every request

1. Preflight, not postflight. Character counts, media formats, URN patterns, audit states, OAuth scope mismatches, YouTube quota — all validated locally before the upstream call.
2. Transparent errors. Stable letmepost code + the specific rule that failed + the raw platform body + a remediation hint. Always.
3. Pinned platform versions. We pin the header, track deprecations, upgrade internally. Your workflow doesn't break at 2 a.m. when LinkedIn sunsets v202412.
4. Idempotency by default. Every write accepts an Idempotency-Key. Retries are safe — no double-posting loops when a worker restarts mid-publish.

What it looks like

Request:

curl -X POST https://api.letmepost.dev/v1/posts \
  -H "Authorization: Bearer lmp_live_…" \
  -H "Idempotency-Key: $(uuidgen)" \
  -H "Content-Type: application/json" \
  -d '{
    "targets": [{ "accountId": "acc_…" }],
    "text": "Shipping letmepost.dev"
  }'

Failure:

{
  "error": {
    "code": "preflight_failed",
    "rule": "bluesky.text.max_graphemes",
    "platform": "bluesky",
    "platformVersion": "atproto-2026-04",
    "message": "Post text is 312 graphemes; Bluesky allows at most 300.",
    "remediation": "Shorten the post to 300 graphemes or fewer.",
    "docUrl": "https://docs.letmepost.dev/errors/preflight_failed",
    "ruleUrl": "https://docs.letmepost.dev/preflight/bluesky-text-max_graphemes",
    "requestId": "req_01HY6X4AWBJM2K9F2PTQMRD9JQ"
  }
}

Same shape across every platform. Same shape on every error class — preflight_failed, platform_auth_failed, platform_rejected, platform_unavailable, rate_limited. The dashboard renders these directly. Your error handler doesn't need a per-platform branch.

Why this exists

Four things developers hit every week with incumbent social-media APIs:

1. Silent failures. Posts report success then never appear. Error bodies come back as {}. Postiz #1321 was an infinite double-post loop; Ayrshare's error 138 masks half a dozen distinct upstream causes.
2. API version churn. LinkedIn sunset five API versions in six months in 2024–2025; every sunset broke n8n Cloud, Zapier, Make, Pabbly, and Postiz. The fix in every case was a one-header swap.
3. Async media rejections. YouTube's restricted-scope mismatches surfacing as generic forbidden, Threads's OAuthException 2207052, Instagram Reels rejecting Google Drive URLs — all catchable client-side, all unhandled by the incumbents.
4. Per-profile pricing. $6–$12 per channel, per month, forever. Universally hated; nobody has built around it. We don't charge it.

letmepost.dev addresses all four, in one API.

Platform support

live = production-ready end-to-end. trial = connect works but rate-limited or sandboxed (X on Pay-Per-Use, Pinterest on Trial Access). pending = approval in flight; the publisher is built and ships the moment review clears. planned = built into the schema, publisher pending.

TikTok is deferred to v2 — schemas + DB enum keep it reserved so the v2 add is additive. Reddit, Telegram, Discord, Snapchat, Google Business, and WhatsApp are deliberately cut from v1. Reasoning in PRODUCT.md.

Quickstart

# 1. Sign up + grab a key
open https://dashboard.letmepost.dev

# 2. Connect Bluesky (or any other platform via OAuth)
curl -X POST https://api.letmepost.dev/v1/accounts/connect/bluesky \
  -H "Authorization: Bearer lmp_live_…"

# 3. Publish
curl -X POST https://api.letmepost.dev/v1/posts \
  -H "Authorization: Bearer lmp_live_…" \
  -H "Idempotency-Key: $(uuidgen)" \
  -d '{ "targets": [{ "accountId": "acc_…" }], "text": "Hello, world" }'

90-second walkthrough at docs.letmepost.dev/quickstart.

Contributing

We build in the open. Outside contributions are how this becomes a primitive for every social platform, not just the eight we shipped first.

Pick a starting point:

• Good first issues — scoped, isolated, no DB-migration archeology required.
• Help wanted — medium tasks the maintainers can't get to.
• Platform requests — Reddit, Mastodon, YouTube, Telegram, Discord, Google Business. Each issue mirrors the same publisher shape (provider + publisher + preflight + client). The walkthrough in CONTRIBUTING.md §3 is the canonical recipe — most additions are < 500 LOC.
• Found a bug? Open one via the bug-report template — auto-applies the right labels and asks for the platform + repro + raw error envelope so triage doesn't ping-pong.

Before you open a PR, skim CONTRIBUTING.md — it documents the layering rules, the error contract, the pre-publish gate pattern, the testing approach (MSW + transaction rollback), and the commit style we follow. It's how new code reviews itself.

CODE_OF_CONDUCT.md · SECURITY.md (vulnerability disclosure) · PRODUCT.md (the seven product principles) · TECH.md (stack contract) · plan.md (v1 status + pre-launch checklist).

Self-host

Apache 2.0 from day 0. The same code that runs api.letmepost.dev runs on your own infra — no feature gate, no open-core trick.

git clone https://github.com/rosekamallove/letmepost.dev
cd letmepost.dev
pnpm install
cp apps/api/.env.example apps/api/.env             # fill in your platform OAuth credentials
docker compose -f docker-compose.dev.yml up -d     # spins up Postgres + Redis only
pnpm --filter @letmepost/api db:migrate
pnpm dev                                           # API + dashboard in watch mode

The dev compose file ships Postgres + Redis. The API, worker, and dashboard run via pnpm — see docs.letmepost.dev/self-host/quick-start for the full walkthrough and self-host/deploying for production patterns. BYO Postgres (or Neon), BYO Redis (or Upstash), BYO platform credentials. Hosted is permanently optional.

Running locally (development)

Prerequisites: Node >=24, pnpm 10.33.0+ (corepack enable).

pnpm install
pnpm dev            # API + web + dashboard in watch mode (turbo)
pnpm test           # vitest across the workspace
pnpm typecheck
pnpm build

Individual apps:

pnpm --filter @letmepost/api dev        # API → http://localhost:3000
pnpm --filter @letmepost/dashboard dev  # Dashboard → http://localhost:3001
pnpm --filter @letmepost/web dev        # Landing → http://localhost:4321

Repo layout

apps/
  api/                 # Hono HTTP API + BullMQ workers — the core product
  dashboard/           # Next.js operator surface (dashboard.letmepost.dev)
  web/                 # Astro landing site (letmepost.dev)
packages/
  schemas/             # Zod — single source of truth for validation, types, OpenAPI
  sdk-ts/              # @letmepost/sdk — official TypeScript client (npm)
  config-tsconfig/

Landing as the stack grows: packages/openapi/ (generated 3.1 spec), plus sibling repos letmepost/sdk-python and letmepost/sdk-go auto-generated from the spec. See TECH.md for the full target tree.

Tech stack

Hono · BullMQ · Drizzle · PostgreSQL (Neon) · Redis (Upstash) · better-auth · Zod · Next.js · Astro · TypeScript · Turborepo · pnpm.

API contract details in TECH.md. Product principles in PRODUCT.md. Roadmap in plan.md.

Compliance

• letmepost.dev is an open-source, self-hosted-capable social media publishing API.
• The hosted service uses official, platform-approved OAuth flows for every platform (Bluesky app-password is the documented Bluesky-supported alternative; everything else is OAuth 2.0 or OAuth 2.0 + PKCE).
• letmepost.dev does not scrape content from social media platforms — every read or write is through the platform's documented API.
• letmepost.dev does not collect, store, or proxy API keys or access tokens belonging to the integrating developer's end-users. Users authenticate directly with the social platform; tokens are AES-256-GCM encrypted at rest with per-row data keys.
• letmepost.dev never asks users to paste API keys into the hosted product UI.
• Self-host users supply their own platform credentials; no telemetry, no license check, no phone-home.

Star history

License

Apache 2.0. Permissive by design — you can build a commercial product on top of letmepost.dev without copyleft contagion. Same code in hosted and self-host.