Substack Publication Cadence Brief

Unofficial — independent tool, not affiliated with, endorsed by, or sponsored by Substack. It reads only publicly visible pages. Support, reliability guarantees and the full disclaimer are at the bottom of this page.

Compare the recent publication cadence of public Substack newsletters from their RSS feeds. One row per publication helps an editor or sponsor researcher spot active and quiet newsletters and open recent post links. This tool is independent of Substack.

Input

Give one to five lowercase publication slugs on *.substack.com, default simonowens and garymarcus. Set lookbackDays from 1 to 30 (default 14) and maxPostsPerPublication from 1 to 10 (default 5). Redirecting custom-domain publications are unsupported in v1.

Output

One row per validated feed, in input order, includes recent post count, latest title/link/date, active or quiet status, up to the requested number of post title/link/date triples, and a feedWindowTruncated flag. A quiet row is a real negative observation. RSS exposes at most a recent window, usually 20 items; counts do not claim a complete archive. No full post content is provided.

Pricing

One publication-brief-created PPE event at $0.003 per delivered row, including valid quiet rows; no start or secondary event. Two successful publications cost $0.006. Failed retrieval or malformed source before delivery is not charged. Dataset row count must equal the event count.

Limits

Only public /feed paths are fetched after robots verification. Maximum five publications, 10 requests, 2 MiB per feed, 256 MB and 180 seconds; direct HTTP only, at least one second between requests, no proxy/browser/API key/paid source. All selected sources are validated before delivery. Redirects, 403, 429, malformed XML, missing identity or dates, and timeouts fail explicitly; a failed source never becomes a quiet row.

Privacy

Store only post titles, public links and dates plus publication-level status. No full article, author profile, email, reviewer identity, contact URL, image or raw XML is persisted. Public RSS is attributed to its source publication; this Actor is unaffiliated with Substack.

If something goes wrong

• Wrong number or a failed run? Open a ticket on the Issues tab. I read every one and reply within 2 business days (Japan time).
• You never get a fake "empty" result. If the site can't be read, the run fails and says so.
• Validated briefs only. One publication brief is one billable event, including a source-verified quiet period. Failed source retrieval is not charged.
• Checked every week. An automatic test runs this tool weekly; if the site changes, I fix it.
• Public RSS data only. No login, subscriber records, contacts or full post text.

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Disclaimer

Unofficial, independent tool — not affiliated with, endorsed by, or sponsored by Substack. Product names and logos belong to their owners and only say where the data comes from. Data is read from public pages, for market research; check before you act on it.