posterly

MCP connector

Lemmy MCP server

Post to Lemmy communities on any instance from Claude or ChatGPT.

This is the posterly MCP server, used for Lemmy. The same connection works from Claude, ChatGPT, Cursor, and other MCP clients. It is not a separate Lemmy-only download.

Get Starter + API · $10/moHow to connect the MCP server

What you can do on Lemmy

Lemmy is a federated forum network, and every post lives in a community. Your AI client connects to the instance you use, such as lemmy.world, and posts under your account with a title, an optional link, and a Markdown body of up to 10,000 characters.

Every post needs a community, written as technology or technology@lemmy.world, and each post can target a different one, so one campaign can reach several communities in a single session. Set a URL to make it a link post, and an attached image is used as the link if you do not give one. Mark anything sensitive as NSFW.

Lemmy communities have their own rules and moderators, so draft with the community in mind and paste the rules into the chat so the assistant can follow them. Accounts with two-factor (TOTP) login cannot connect, because the connection uses your username and password. The MCP server does not read Lemmy analytics.

  • Text posts
  • Images
  • Multi-image

Post types: text, image. Analytics are not read for this platform.

Tools

These are the tools your AI client uses for Lemmy. Ask it to call list_platforms with view=schema and the account_id before it sets anything specific to Lemmy.

Account and connection

  • whoamiWho am I

  • list_accountsConnected accounts

  • list_platformsPlatforms

  • create_connect_sessionStart a connect session

  • connect_accountConnect with credentials

Posts

  • validate_postValidate a post

  • create_postCreate a post

    Show the caption, account, and time, then wait for confirmation before confirm=true.

  • create_posts_batchCreate posts in bulk

    1 to 25 posts in one confirmed request.

  • update_postEdit a post

    Show the caption, account, and time, then wait for confirmation before confirm=true.

  • list_postsPosts

  • get_postOne post

  • delete_postDelete posts

    Live removal needs an eligible connection and confirm_published. A refusal keeps the posterly record.

  • find_available_slotFind a free slot

  • generate_captionsGenerate captions

Media

  • upload_mediaUpload media

    Hosted requests are about 4MB, so this path is for small files. Large files use create_signed_upload or create_media_drop.

  • create_signed_uploadSigned upload link

  • create_media_dropMedia drop link

  • list_mediaMedia library

How to connect

  1. Add the hosted server in Claude, ChatGPT, Cursor, or another MCP client. Server URL: https://www.poster.ly/api/mcp. Sign in with posterly OAuth and press Allow. Use the www host. In ChatGPT, write actions need a Business, Enterprise, or Edu plan.
  2. Or, in a client that can run a local process (Cursor, Claude Code, Windsurf, and similar), use npx -y posterly-mcp-server@latest with a POSTERLY_API_KEY placeholder in that client's MCP config.
  3. Call whoami and list_accounts so you know which workspace the client is using.
  4. Connect Lemmy with the method below, then call list_platforms with view=schema and the account_id.

Lemmy

Paste your credentials into the dashboard form. You can also give them to your AI client, but anything you type into a chat becomes part of that chat history.

  • Instance domain (required): Lemmy instance domain, for example lemmy.world.
  • Username (required): Lemmy username or email.
  • Password (required): Lemmy account password (accounts with TOTP enabled are not supported).
Connect Lemmy in the dashboard

Example prompts

  • Post this link to the technology community on lemmy.world with the title "Show: our open API" and a short description.
  • Share this write-up in selfhosted@lemmy.world and opensource@lemmy.ml, with a title that fits each community.
  • Schedule a text post in my community for Friday evening and mark it NSFW.

Lemmy limits

Caption or text
10,000 characters.

Request rates depend on your plan. The posterly MCP page lists them.

Pricing

API and MCP access is an add-on to any posterly plan. Starter plus API is $10 a month, charged now with no free trial on this checkout.

Get Starter + API · $10/moSee every plan

FAQ

What is the Lemmy MCP server?

It is the posterly MCP server, not a separate product. Connect it once and the same connection covers Lemmy and 17 other platforms, from Claude, ChatGPT, Cursor, and other MCP clients.

How do I connect Lemmy?

Add the hosted server at https://www.poster.ly/api/mcp and sign in with posterly, or run npx -y posterly-mcp-server@latest in a client that can start a local process. Lemmy: Paste your credentials into the dashboard form. You can also give them to your AI client, but anything you type into a chat becomes part of that chat history.

How do I pick the Lemmy community for a post?

Name it in the request, like technology or technology@lemmy.world. Every post needs one, and each post can target a different community.

Can I connect a Lemmy account that uses two-factor login?

No. Accounts with TOTP enabled are not supported, because the connection uses your username and password.

Keep reading

MCP

posterly MCP server

Hosted OAuth setup, the local npm package, and the full tool list.

Scheduler

Lemmy scheduler

Schedule Lemmy from the posterly calendar and composer.

Guide

Lemmy guide

Read the long Lemmy guide, then come back to connect it.

Pricing

posterly pricing

Compare plans, then add API and MCP at checkout.

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