Socialync MCP server

Socialync MCP Server

Official documentation, registry manifest, and Cursor plugin for the Socialync hosted MCP server. Socialync is a cross-posting and scheduling tool for creators: upload once, publish to TikTok, Instagram, YouTube, Facebook, X, LinkedIn, Threads, and Bluesky.

This MCP server lets Claude, ChatGPT, Cursor, Grok Bot, and any MCP-compatible AI agent draft, schedule, and publish social media posts through your own OAuth-authorized Socialync account, with human-in-the-loop approval built into the workflow.

Every platform integration runs on the official platform API. No browser automation, no scraping, no unofficial endpoints. Your agent cannot get your account restricted on our behalf.

Duplicate protection means a retry can never publish twice, and failed posts are retried automatically. Both matter when an agent is doing the posting.

Note: Socialync's server is hosted (remote) and closed source. This repository contains the documentation, the MCP Registry manifest, and the Cursor plugin files only. There is nothing to install or run from here.

Endpoint

https://mcp.socialync.io/mcp

Transport: Streamable HTTP. Discovery document (tools, platforms, auth, limits, as JSON): https://mcp.socialync.io/.well-known/mcp

MCP and API access are on the free plan. $0, no credit card, 5 posts a month across all 8 platforms. Your agent can connect and publish without anyone reaching for a card. Paid plans start at $20/month for unlimited posts and 5 connected accounts (Starter $20, Creator $30 for 10 accounts, Studio $60 for 25, Agency $99 for 100). Plans and pricing.

Limits worth knowing: 1 API key per brand, and 10 AI-created posts per day per brand on paid plans (5 on free).

Authentication, two ways

A) OAuth 2.0 (preferred). Add the URL with no headers. Your client registers itself (dynamic client registration, PKCE, no client secret), opens a browser, and you sign in with your Socialync account and choose which brands the agent may manage. This is what Claude.ai, Claude Code, Cursor, and ChatGPT do on their own.

B) Bearer API key. For clients that cannot complete a browser OAuth flow (Grok Bot, headless agents, hand-edited config files). Generate a key at https://www.socialync.io/api-keys and send Authorization: Bearer . One key per brand, included on every plan. Never commit the key.

OAuth callbacks known to work end to end (any https redirect URI plus http://localhost and http://127.0.0.1 on any port is accepted):

• https://www.cursor.com/agents/mcp/oauth/callback
• http://localhost:8787/callback
• https://claude.ai/api/mcp/auth_callback
• http://localhost/callback
• http://127.0.0.1/callback

Connect

Claude (claude.ai): Settings, then Connectors, then "Add custom connector", and paste the endpoint URL above. Full walkthrough: Socialync MCP connector guide.

Claude Code:

claude mcp add --transport http socialync https://mcp.socialync.io/mcp

Cursor / Grok Bot (OAuth, url only):

{
  "mcpServers": {
    "socialync": {
      "url": "https://mcp.socialync.io/mcp"
    }
  }
}

Grok Bot or any client that cannot complete OAuth (Bearer key):

{
  "mcpServers": {
    "socialync": {
      "url": "https://mcp.socialync.io/mcp",
      "headers": {
        "Authorization": "Bearer YOUR_SOCIALYNC_API_KEY"
      }
    }
  }
}

Grok Bot runs OAuth from Cursor's cloud, not your machine. The same URL can work in the Cursor IDE and fail in Grok Bot. Test in Grok Bot under Settings, then Plugins, not only in the IDE. If OAuth never starts or you see "fetch failed", use the Bearer key form.

OpenClaw:

openclaw mcp add socialync --url https://mcp.socialync.io/mcp --transport streamable-http
openclaw mcp login socialync

Other MCP clients (generic config):

Shortened. The full README is on GitHub.