Substack hosts many of the most-read independent newsletters, and the data around them is useful. Sponsors want to know how big a newsletter really is. Researchers want the full text of posts. Media teams track what competitors publish and how readers react.

Substack has no official public API for this. The data is visible in the browser, though: post pages, comment threads, the archive, and the "Over 466,000 subscribers" line on a publication's homepage. This guide shows how to collect it in a structured way without logging in, using the Substack Scraper on Apify.…