Circles Companion

Connects your Substack session to Circles CRM and adds people to your lists.

Circles Companion connects Substack to Circles, a free, open-source relationship CRM for Substack writers. You host Circles yourself, and this extension links your Substack account to it. WHAT THE EXTENSION DOES • Pair with your own server: enter your Circles address in the toolbar popup. The extension only gets access to that single site. To switch servers, pair a different one. • Connect Substack in one click: start the connection from Circles' settings and the extension links the Substack account you're logged into. You don't paste any cookies. • Add people from anywhere on Substack: an "Add to Circles" button sits next to authors on Notes, posts and profiles. A confirmation step shows the person's Substack profile so you save the right one, and the button shows which lists they're already in. • Quick add from the popup: open the popup on any Substack profile. It recognizes the person, and you can add them with lists and tags. • Keep conversations in sync: as you browse, it records the replies, Notes threads and notifications Substack has already loaded. Your timelines stay current without extra requests to Substack. • Track your own engagement: the likes, restacks, comments and replies you make are recorded once Substack confirms them. Unliking or unrestacking removes them again. • Never lose a capture: if your server is unreachable, captures wait in a queue and are retried. They're tied to the Substack account you connected, so nothing is ever delivered to a different account. WHAT YOU GET IN CIRCLES • Contacts merged by Substack profile, with separate scores for engagement you receive and engagement you give • Full interaction timelines for each contact, with the Note or post each one happened on • Queues for people who need a reply, drifting relationships and priority contacts, plus lists and tags • Comment triage for your Notes and articles • Background sync of notifications, followers and subscribers, plus resumable imports of older history • Note scheduling: write and schedule Substack Notes, and Substack publishes them on time • An optional MCP server that gives AI assistants permission-controlled access to your CRM PRIVACY The extension uses the Substack session you're already logged into. Your session cookie is sent only to the Circles server you paired, which stores it (encrypted if you turn that on) so it can sync your account. Your Substack password is never asked for or stored, and nothing is sent anywhere else. REQUIREMENTS A Circles server you run yourself. Setup instructions and source code: https://github.com/cucoleadan/circles-app DISCLAIMER Circles Companion is an independent open-source tool. It is not affiliated with, endorsed by or sponsored by Substack, Inc.