What this checks
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Five categories, weighted the way they affect whether a visitor subscribes: Positioning and clarity (35), Conversion (25), Brand and trust (15), Activity and consistency (15), Discovery and SEO (10). Each check tells you what was detected, why it matters and what to change.
The score is deterministic — no AI decides it. Anything the page does not let us measure is reported as Not assessed and excluded from the total, so a missing signal never quietly costs you points. AI is used for one thing only: judging whether your wording makes the value and the audience clear, and suggesting a sharper tagline. It never decides whether something exists.
What it reads, and what we keep
It reads your public profile — the same thing any visitor or search engine sees, plus the public data Substack itself serves to logged-out readers (your latest post and Note, your bio, the links you configured). No subscriber data, no private stats, no login.
We keep the result of each audit: the handle, the public name and image, and the scores. That is what lets a shared report show its score in the link preview, what powers the median you are compared against, and what lets you see how your score has moved since your first audit. Only public data is kept — never subscriber data, private stats, emails, or anything behind a login. A good score is not a growth promise either: it means your profile is well implemented, not that people will subscribe.
Questions
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Is the Substack profile audit free?
Yes — no account, no signup, no card. Paste a public Substack URL and you get the full report. It is the same audit the Subshack Chrome extension runs, made available on the web so you can audit a profile without installing anything.
Can I audit someone else’s Substack?
Yes. The audit only reads the public profile page — the same thing any visitor or search engine sees. There is no private or subscriber data involved, so you can run it on your own publication or on one you want to learn from. Custom domains work too: most established publications redirect their .substack.com address to their own domain, and the tool follows it.
How is the score calculated?
Deterministically, with no AI deciding the number. Five weighted categories — Positioning 35, Conversion 25, Brand and trust 15, Activity 15, Discovery and SEO 10 — split across their checks. Pass scores 100% of a check’s weight, To improve 50%, Error 0%. Anything that cannot be assessed is excluded from the total, so it never inflates or lowers the score.
Do you store the audits?
Yes, and only what is public: the handle, the public name and image of the publication, and the scores. That is what lets a shared report show its score in the link preview, what powers the median your score is compared against, and what lets you track how a profile evolves — each audit is kept, so you can see the before and after of any change you make. Never subscriber data, private stats, emails or anything behind a login.
Why does my score compare to a median?
Because a number on its own says little. Knowing that 72 sits above or below what other publications score tells you whether to act. The median is computed only from audits where every check could be evaluated, so you are compared with complete reports, and it only appears once enough profiles have been audited for the comparison to mean anything.
Fixing the profile is the first step; the next one is what you post. Start with Notes that get replies and the numbers that matter. To run this audit — plus drafting and replies — from inside Substack itself, get the Chrome extension.
The experiments behind this tool
Subscribe on Substack →Every check comes from experiments run in public on Subshack Growth, with the real numbers — including the ones that did not work.