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3 posts tagged “substack”

2025

I just sent out the latest edition of the newsletter version of this blog. It's a long one! Turns out I wrote a lot of stuff in the past 10 days.

The newsletter is out two days later than I had planned because I kept running into an infuriating issue with Substack: it would refuse to save my content with a "Network error" and "Not saved" and I couldn't figure out why.

Screenshot of the Substack UI, with a Network error message on purple and a Not saved message higher up. The content in that editor includes an explanation of a SQL injection vulnerability.

So I asked ChatGPT to dig into it, which dug up this Hacker News post about the string /etc/hosts triggering an error.

And yeah, it turns out my newsletter included this post describing a SQL injection attack against ClickHouse and PostgreSQL which included the full exploit that was used.

Deleting that annotated example exploit allowed me to send the letter!

# 28th December 2025, 4:16 am / sql-injection, security, newsletter, substack

How I automate my Substack newsletter with content from my blog

Visit How I automate my Substack newsletter with content from my blog

I sent out my weekly-ish Substack newsletter this morning and took the opportunity to record a YouTube video demonstrating my process and describing the different components that make it work. There’s a lot of digital duct tape involved, taking the content from Django+Heroku+PostgreSQL to GitHub Actions to SQLite+Datasette+Fly.io to JavaScript+Observable and finally to Substack.

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2023

Semi-automating a Substack newsletter with an Observable notebook

Visit Semi-automating a Substack newsletter with an Observable notebook

I recently started sending out a weekly-ish email newsletter consisting of content from my blog. I’ve mostly automated that, using an Observable Notebook to generate the HTML. Here’s how that system works.

[... 2,520 words]