Show HN: I updated my unofficial Substack Posting API

A couple of days ago, I released my version of an unofficial Substack API. The main difference between it and all the other solutions available on the market is that it can actually post content, create tags, add images, save drafts, and so on. In other words, it is specifically a posting API. It is not designed to fetch posts or search for content — it is designed to publish something.

The API is focused on allowing users to use it for publishing on Substack. It includes a CLI and an MCP, meaning the API is fully ready to work with AI agents.

However, when users started signing up, I realized that most of them were not technically advanced users. For them, it was unclear what CLI, MCP, or APIs were, what keys were, where to add them, and so on.

So I decided to improve the project. I added one-click synchronization, allowing any blog from any website to be fully synchronized with Substack. All you need to do is add a link to your website, and the synchronizer will automatically find all the posts on your blog. Then you can configure a synchronization schedule — for example, one post per day, two posts per day, three posts per day, or everything at once.

The system will automatically monitor updates on your website and publish them to Substack.

The difference compared to Substack’s import feature is that with Substack import, you export all your posts and import them into Substack once. Basically, you are moving your website. My system is designed so that you do not move your blog — instead, you turn Substack into a cross-posting channel for your existing blog.

So the goal is not to migrate your blog, but to cross-post content and build a new audience. In reality, this is more of a marketing tool than a technical one.

That is why I am posting here for the second time — because I have released a major update.