Which Social Media Scheduler Has an API and an MCP Server for Claude and ChatGPT? PostFast, on Every Plan

PostFast has both: a REST API and an official MCP server, included on every plan, including the 7-day trial, with no per-seat and no per-conversation charge. The hosted connector at https://mcp.postfa.st/mcp signs in over OAuth and works inside ChatGPT and the Claude app (26 tools). The local server, npx -y postfast-mcp, runs in Claude Code, Claude Desktop, VS Code, Cursor and other MCP clients that run local servers (24 tools). Both drive the same account across 11 platforms: Instagram, Facebook, TikTok, LinkedIn, YouTube, Threads, Pinterest, Bluesky, Telegram, X and Google Business Profile.

This guide covers the two ways to connect, what an assistant can do once connected, the REST API for your own automations, and the limits that apply. Every product fact was checked in early September 2026 against PostFast's API documentation and integration pages.

Two ways to connect an AI assistant

The two tool sets are the same core: list accounts, create and schedule posts (up to 15 per request), upload media, delete posts, post analytics, follower history, TikTok sounds, Pinterest boards, YouTube playlists, places for geotags, and the Social Inbox (list conversations, reply, assign, mark read). The hosted connector drops the signed-upload-URL tool and adds approve posts, list workspaces and upload from a URL.

Connect PostFast to ChatGPT

1. Open ChatGPT, go to Settings, then Connectors (it may read "Apps and Connectors").
2. Scroll to Advanced and turn on Developer mode.
3. Choose Create, give the connector a name, and paste https://mcp.postfa.st/mcp.
4. Approve the OAuth sign-in. No client secret, no API key.

You need a paid ChatGPT plan with Developer Mode enabled; the Free plan cannot add custom connectors. Developer Mode supports full actions, so scheduling and publishing work, and ChatGPT shows a confirmation before anything posts. On Business, Enterprise and Edu workspaces an admin enables custom connectors first. Full steps and examples: ChatGPT connector page.

Connect PostFast to Claude

1. In Claude, open Customize, then Connectors.
2. Click the plus, then choose Add custom connector.
3. Paste https://mcp.postfa.st/mcp and leave the OAuth fields blank; Claude discovers them.
4. Approve the sign-in.

Custom connectors work on Claude Free (limited to one custom connector), Pro, Max, Team and Enterprise. On Team and Enterprise an Owner adds it once under Organization settings, then Connectors. Details: Claude connector page.

Connect Claude Code, Cursor, VS Code or Claude Desktop

Open API in the PostFast sidebar and generate a key, then add the server to the client's MCP configuration:

{
  "mcpServers": {
    "postfast": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "postfast-mcp"],
      "env": { "POSTFAST_API_KEY": "your_api_key" }
    }
  }
}

Test it with MCP Inspector: if the tool list shows 24 tools, the server is wired up. The Claude Code guide has example prompts that work, and the MCP server page documents the tools.

What an assistant can do once connected

• Draft a week of posts, then schedule them to specific accounts at specific times, or save them as drafts for review.
• Attach media by uploading a file (or a URL through the hosted connector), and set the platform options in words: Reel or feed post, TikTok draft or direct publish, YouTube title and privacy, a Pinterest board, a LinkedIn document post, a Google Business Profile event with a call-to-action button.
• Pull analytics for published posts and follower history for an account, then plan the next batch from the numbers.
• Work the comment inbox: list new comments, reply, mark read, assign to a teammate, or send an Instagram private reply (one per comment, within 7 days).

The REST API for your own automation

The same capabilities are available directly, for a CMS connector, a CI job, or a custom agent:

• Authenticate with the pf-api-key header (the key from the API page in the sidebar).
• POST /social-posts creates and schedules up to 15 posts per request; each post carries its text, the target account ID, media keys from the signed-upload step, a UTC scheduledAt (in the future, within one year), and status SCHEDULED or DRAFT. Platform controls (Instagram publish type, TikTok draft and music, YouTube fields, Pinterest board, LinkedIn document, Google Business Profile post type) are fields on the request.
• Media: request signed upload URLs, PUT the file, then reference the returned key. Up to 250 MB per video and 10 MB per image.
• Rate limits: post creation allows 350 requests per day and 150 per minute per workspace, and the key as a whole is limited to 60 requests per minute and 2,000 per day. Scheduling to a disconnected account returns 400; saving it as a draft still works.
• Full reference at postfa.st/docs.

A simple pipeline that holds up

1. Identify the target account. Fetch your connected accounts once and cache their IDs.
2. Prepare media. Ask for signed upload URLs and push images or video with a PUT request; save the returned keys.
3. Create posts. Send one or many posts with text, UTC time, account ID and media keys. Choose scheduled or draft. Add platform controls only when needed.
4. Clean up when plans change. Delete a scheduled item by its ID.

Keep the field names in the docs rather than in your code, keep your own record of what you already sent and check the post list before re-sending (there is no idempotency key), add retries with backoff on upload and schedule steps, and keep one workspace per brand so keys map cleanly to accounts.

No-code routes: n8n, Make and Zapier

If you would rather not touch the API, PostFast has a verified n8n community node plus a ready-to-use n8n workflow that combines the PostFast API with the OpenAI API (the JSON is sent to your email); the n8n social media automation guide covers the node and the free templates. There is a verified Zapier integration with 7,000+ apps and an official Make integration. For a chat-app agent, the MCP server also runs inside NanoClaw, which you message from WhatsApp, Telegram, Slack, Discord or Gmail.

Plans and what it costs

The API and the MCP server come with every plan, from Starter at €12 a month (€10 billed yearly) to Enterprise, and with the 7-day free trial; no credit card is needed to start. Plans differ by social accounts, users, workspaces and the scheduled-post and draft allowances, not by API access.

Frequently Asked Questions

Does PostFast have a public API?

Yes. A REST API with an API key per workspace, documented at postfa.st/docs, included on every plan and the free trial. It creates and schedules posts, uploads media and reads your connected accounts.

Which AI assistants can use the PostFast MCP server?

ChatGPT and the Claude app through the hosted connector at https://mcp.postfa.st/mcp (OAuth sign-in), and Claude Code, Claude Desktop, VS Code, Cursor and other MCP clients that run local servers through npx -y postfast-mcp and your API key.

Do I need a paid ChatGPT plan to connect PostFast?

Yes. Custom connectors need a paid ChatGPT plan with Developer Mode enabled; the Free plan cannot add them. On Business, Enterprise and Edu workspaces an admin enables custom connectors first.

Can Claude Free use the connector?

Yes. Custom connectors work on Claude Free, limited to one custom connector, and on Pro, Max, Team and Enterprise.

What are the API rate limits?

Post creation: 350 requests per day and 150 per minute per workspace, up to 15 posts per request; the key overall: 60 requests per minute and 2,000 per day. Media up to 250 MB per video and 10 MB per image, and scheduled times within one year.

Is there an extra charge for API or MCP use?

No. Both are included on every plan, including the trial, with no per-seat and no per-conversation charge.

Connect once, then ask in plain language

Paste the connector URL into ChatGPT or Claude, or add the npx server to your IDE, and the assistant schedules to all 11 platforms through the same account you use in the app. Start with the 7-day free trial and the MCP server page.