LinkedIn Poster MCP

LinkedIn Poster MCP — Publish to LinkedIn via natural language.

Post to LinkedIn without leaving the chat.

A Model Context Protocol server that turns any MCP client into a LinkedIn publisher — text posts, image posts with alt text, profile lookups, and token-health checks, all driven by natural language instead of the LinkedIn API console.

› Post the launch photo to LinkedIn, caption it about our v2 release.
// MCP tool call resolved automatically
{
  "tool": "create_image_post",
  "caption": "Shipping v2 today",
  "images": ["launch.png"]
}
// polling upload status… AVAILABLE
ok post created — urn:li:share:7183…

Highlights

Related MCP server: linkedin-mcp

MCP tools

Four tools, one bearer token. Every tool call authenticates through the same Redis-backed token — no per-call re-auth.

Architecture

Stateless endpoint, stateful token.

api/
  authorize.ts     GET   start LinkedIn OAuth (CSRF state in Redis)
  callback.ts      GET   exchange code for tokens, store, success page
  mcp.ts           POST  MCP endpoint, bearer-auth, tools
  dashboard.ts     GET   admin dashboard API
frontend/                React + Tailwind + MUI dashboard source -> public/
lib/
  config.ts               env vars, URLs, Redis client
  linkedin-auth.ts        token exchange, refresh, access-token helper
  linkedin-api.ts         profile, create_post, create_image_post
  logging.ts              structured logs to Redis
  errors.ts               NotAuthorizedError, LinkedInError
mcp-stdio.mjs       esbuild-bundled stdio entry

Facts worth remembering:

• Tokens live under a single Redis key, linkedin:tokens.

• /api/mcp is stateless and requires Authorization: Bearer <MCP_AUTH_TOKEN> on every request.

• All LinkedIn calls use raw fetch() — no LinkedIn SDK dependency.

OAuth flow

One authorization, sixty days of posting.

Client -> /api/authorize -> LinkedIn OAuth -> /callback -> Redis -> MCP tools

Note: LinkedIn issues a refresh_token only for apps provisioned with programmatic refresh. On the standard scope set, access tokens last 60 days and the user re-authorizes on expiry — check_auth_status always reports the real state.

Image upload

Why posts never render blank.

1. Register — the server registers the upload and receives a signed uploadUrl.

2. Upload — image bytes are uploaded directly to that signed URL.

3. Poll -> post — status is polled until AVAILABLE, then — and only then — the post is created.

Setup

Prerequisites

• Node.js 24+

• LinkedIn Developer app with approved scopes: openid profile email w_member_social

• An Upstash Redis database

Environment variables

Set these in Vercel and in a root .env for local development:

These files are git-ignored — never commit secrets.

Local development

npm install
vercel dev          # http://localhost:3000/api/...
npm run typecheck   # tsc --noEmit

Redirect URIs

local    http://localhost:3000/api/callback
prod     https://<your-app>.vercel.app/api/callback

Whitelist the exact URL in the LinkedIn Developer Portal — LinkedIn matches redirects with no tolerance for query params.

Client setup

Remote or local — pick one.

• Type: Custom / MCP server, Streamable HTTP

• Endpoint: https://<your-deployed-url>/api/mcp

• Header: Authorization: Bearer <MCP_AUTH_TOKEN>

Point the client at the bundled entry:

node /path/to/linkedin-post-mcp/mcp-stdio.mjs

Deploy

Ship it to Vercel.

vercel           # preview
vercel --prod    # production

• vercel.json pins api/** to the Node.js runtime.

• Set the production callback URL for LinkedIn.

• After deploying, open /api/authorize once — then every tool works.

Security

What's actually guarded.

• Secrets come from environment variables only — nothing is logged.

• Endpoint — the MCP endpoint requires a bearer token before protocol handling.

• CSRF — OAuth state guards against request forgery and is one-time-use with a short TTL.