CrossPoster

You can try CrossPoster right now at crossposter.llamaindex.ai!

CrossPoster is a tool for quickly posting to multiple social media platforms while adapting the content to each platform. It uses LlamaIndex.TS to identify entities within each post and @-mention them appropriately on each platform, and also to shorten the text for platforms with character limits.

It was designed as an internal tool for LlamaIndex and has been open-sourced because it's pretty nifty! But unless you have exactly our social media posting workflow you're probably going to have to do some work to adapt it. Why not contribute your changes back as PRs?

Tech Stack

• This is a pretty standard Next.js app.
• It uses LlamaIndex.TS for the AI logic.
• Web search is done with SerpAPI.
• It is deployed on Render because the serverless functions generated are bigger than Vercel's 250MB limit.

Getting Started

Local dev is straightforward:

npm install
npm run dev

Open http://localhost:3000 with your browser to see the result.

Environment variables

Because it connects to so many different APIs, there are a lot of environment variables. You can set them in a .env file in the root directory. They are:

• BASE_URL: The URL you intend to serve the app from; localhost:3000 in dev
• NEXTAUTH_URL: Same as base URL, used by the oauth library
• NEXTAUTH_SECRET: A random string of your choosing; used by the oauth library
• DATABASE_URL: Users and their access tokens are stored in a Postgres database. You can find the schema in prisma/schema.prisma.
• ANTHROPIC_API_KEY: Anthropic's Sonnet 3.5 does all of the thinking. It also works with OpenAI's GPT-4o and better models.
• SERP_API_KEY: Needed for the web searches
• GOOGLE_CLIENT_ID and GOOGLE_CLIENT_SECRET: Used for the OAuth flow
• TWITTER_OAUTH_1_KEY and TWITTER_OAUTH_1_SECRET: You can only upload images to Twitter's API using OAuth 1.0a so you have to set up an app that has those.
• LINKEDIN_CLIENT_ID and LINKEDIN_CLIENT_SECRET: You need a LinkedIn app with a bewildering array of permissions, including:
  • profile
  • email
  • openid
  • w_member_social
  • w_organization_social

PR ideas

Want to contribute? There are so many ways this could be better!

• Click media upload box to open a file selection dialog (probably a one-liner)
• Make images optional (so easy, I'm just busy!)
• Allow video uploads (I'm actually not sure why this doesn't already work)
• Mastodon support (please!)
• Threads support
• Generate links to mentioned entities, maybe with previews, so it's easy to check you got the right ones
• Make the UI prettier
• Schedule posts and show them in a calendar (very large)