Brings letmepost.dev's cross-platform publishing API into any MCP-compatible agent. You get one-shot posting across Bluesky, X, LinkedIn, Threads, Instagram, Facebook, Pinterest, and YouTube through the /v1/posts endpoint, plus account connection flows for each platform. The underlying service validates character limits, media formats, and platform-specific rules before the upstream call, so you catch Bluesky's 300-grapheme limit or YouTube quota issues client-side instead of silently failing. Useful when you're building agent workflows that need to publish content programmatically without wrestling with eight different OAuth flows and API versioning headaches. Self-hostable under Apache 2.0 if you want to run your own instance.
LMP_API_KEY*secretYour letmepost.dev API key (lmp_live_... or lmp_test_...). Create one at https://dashboard.letmepost.dev/api-keys.
LMP_API_BASEOverride for self-hosted deployments. Defaults to https://api.letmepost.dev.
An open-source social media publishing API that fails loudly. One
POST /v1/postsacross 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
Idempotency-Key. Retries are safe — no double-posting loops when a worker restarts mid-publish.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.
Four things developers hit every week with incumbent social-media APIs:
{}. Postiz #1321 was an infinite double-post loop; Ayrshare's error 138 masks half a dozen distinct upstream causes.forbidden, Threads's OAuthException 2207052, Instagram Reels rejecting Google Drive URLs — all catchable client-side, all unhandled by the incumbents.letmepost.dev addresses all four, in one API.
| Platform | Status | Notes |
|---|---|---|
| Bluesky | live | App-password auth, video via dedicated transcoder, 300-grapheme preflight |
| X / Twitter | trial | OAuth 2.0 PKCE, 280 graphemes (t.co-aware), 4 images OR 1 video, threads & quote tweets |
| trial | v5 API, image + video pins, board-required preflight | |
| pending | Versioned REST, 3,000-grapheme commentary, MDP-gated for org posts | |
| Threads | pending | Standalone OAuth at threads.net, 500-char, 2–20 mixed-media carousels |
| pending | Meta Graph, Reels + carousels, FB Login fan-out | |
| Facebook Pages | pending | Meta Graph, single video OR 10 photos |
| YouTube | planned | Data API v3, CASA-gated for production verification |
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.
# 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.
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:
CONTRIBUTING.md §3 is the canonical recipe — most additions are < 500 LOC.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).
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.
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
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.
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.
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.
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