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.

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.

Contributing

Building in the open. File an issue when something's weird. Read PRODUCT.md before PRs that touch product surface area, TECH.md for implementation decisions, and CONTRIBUTING.md for layering rules + the error contract.

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.