I automated my Substack notes to Twitter (completely free)

Every time I publish a note here on Substack, it automatically posts to Twitter within 5 minutes. No Zapier, no Buffer, no manual copying. Just pure automation.

How it works:

1. GitHub Actions scrapes my Substack notes API every 5 minutes

2. When a new note appears, another workflow kicks in

3. It posts directly to Twitter using the API v2 (free tier: 1,500 tweets/month)

4. A .published marker file tracks which notes have been tweeted

Why I built this:

I decided to use Substack more actively for my quick thoughts and updates. But I didn't want to ignore Twitter in the process completely.

I looked at Zapier ($20/mo) and Buffer ($6/mo) - both felt like overkill for "just post this text to Twitter." So I spent an afternoon with Claude Code building a free alternative.

Now I can write once on Substack and my thoughts automatically flow to Twitter. No friction, no double-posting.

The tech stack:

• GitHub Actions (cron: every 5 minutes)

• Twitter API v2 (free tier, no credit card)

• Python + tweepy

• Marker files for duplicate prevention

What I like about it:

• ✅ Completely free (within Twitter's 1,500 tweets/month)

• ✅ No third-party dependencies

• ✅ Tweet URLs saved in each note folder

• ✅ Smart truncation at word boundaries

• ✅ Open source, easy to modify

The whole setup is here if you want to clone it:

Built with Claude Code in one afternoon. AI-native development is wild.

Let’s see if this gets automatically posted to Twitter (yeah, I know now it is called x) ;)