Substack

This connector reads one Substack publication through the public JSON endpoints its own website uses (Substack has no documented public API). Everything is read-only and needs no key; paid-only posts show their preview, not the full text.

Getting credentials: none. Set SUBSTACK_PUBLICATION_URL to the publication's home address, nothing after the domain: https://yourname.substack.com or a custom domain such as https://www.lennysnewsletter.com. A profile link (https://substack.com/@handle), a note link (https://substack.com/@handle/note/c-123) or a post link does not work. To find the address from a profile: open substack.com/@handle, click the publication shown on the profile, and copy the address bar up to the domain. In an app share link open.substack.com/pub/NAME/p/..., NAME is the subdomain: use https://NAME.substack.com. A *.substack.com address of a publication with a custom domain is redirected and also works.

Workflow: substack_list_posts first (newest, or sort=top for most liked). Then substack_get_post_by_id with a post id, or substack_get_post_by_slug with the part after /p/ in a post link, for the full body_html. substack_get_comments reads the discussion. substack_find_publication_by_handle turns an @handle into the writer's publication subdomain and custom domain.

Formats and gotchas: dates are ISO 8601 UTC. audience is everyone, only_paid, founding or only_free. A 404 on every tool means there is no publication at the configured address; an HTML page instead of JSON means the address is a profile or a non-Substack site.

Pagination and limits: list and search tools take limit (1 to 50, the API rejects more) and offset; page with offset += limit until fewer than limit posts come back. Substack publishes no rate limit; keep to about one request per second.

Cloud reachability: all *.substack.com addresses, custom domains and substack.com are public HTTPS, reachable from AnythingMCP Cloud and from self-hosted installs with internet access.