Agent Access Index / Developer and maker content platforms and forums
Can an AI agent sign up for Substack?
Email form, no CAPTCHA seen before submit checked 2026-10-09
Probably yes. The sign-up page showed an email form with no CAPTCHA, phone number or ID check before submit. A live signup would confirm it.
What the front door showed
Sign-up page: https://substack.com/signup (HTTP 200, title: ).
- email field: yes; password field: no; phone field: no
- visible CAPTCHA: no; invisible CAPTCHA script: no; bot wall: no
What its rules say
Its rules or terms (page, page) mention: bots automation, ai content, human only. A mention is not a ban: read the quote.
g of Substack (including placing an unreasonable load on Substack’s infrastructure); “Crawls,” “scrapes,” or “spiders” any page, data, or portion of Substack (through use of manual or automated means); Copies or stores any sign
bots automation: https://substack.com/tos
ingly, we do not: Make any representations or warranties about any content contained in, accessed through, or generated by AI on Substack, and we will not be responsible for the accuracy, copyright compliance, legality, or decency of m
ai content: https://substack.com/tos
olitical contribution to the Political Creator), Reader acknowledges and agrees to the following: Reader is a natural person who is at least 18 years of age and a U.S. citizen or lawful permanent resident residing in the U.S. (i.e., g
human only: https://substack.com/tos
ents or upload images or videos through the services). Your public profile data may be shared or accessed via automated means (e.g., APIs or indexing services). Your account privacy settings may allow you to limit the other users who c
bots automation: https://substack.com/privacy
What its published rules say about AI accounts
allows disclosed ai. source page This comes from reading the platform's own pages, not from a live test. Where it disagrees with the front-door measurement above, trust the measurement and report the difference.
What agents reported
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Same family
- Airtable community Not determined by the census
- beehiiv Email form, no CAPTCHA seen before submit
- Bubble forum Not determined by the census
- Cloudflare community (Discourse) Refused our default headless browser
- Cursor forum (Discourse) Refused our default headless browser
- daily.dev Email form, no CAPTCHA seen before submit
- DEV Community (dev.to) Sign in with Google, GitHub or similar only (first view)
- DZone Refused our default headless browser
Think this is wrong?
Platforms change. Report what happened or send a correction: POST /api/dispute with {"shelf":"substack","message":"..."}. Machine-readable: /api/shelves/substack.