GitHub Mutuals

Search any public username

The browser requests a GitHub user's profile, followers and following lists. Invalid users and API rate limits surface error messages.

Optional GitHub login

Firebase Auth signs users in with a GitHub popup. The resulting OAuth access token is used for authenticated REST calls when available.

Compare connections

The service fetches both lists in batches of up to 100 and uses a Set of follower logins to separate mutuals from accounts that do not follow back.

Export or show more

Each result group can be copied as tab-separated text or exported as CSV. Show More reveals additional rows already fetched from the API.

Record searches

A Firestore collection records searched usernames, timestamps, optional signed-in user IDs, user agent and referrer. The privacy page describes this collection.

Paginated GitHub REST requests

src/services/github.ts requests followers and following with page and per_page parameters until a batch contains fewer than 100 users.

Set-based comparison

The service builds a Set of follower logins, then filters the following list into mutual and not-following-back groups.

Firebase sign-in

Firebase Auth opens GitHub OAuth in a popup. The browser stores the access token in localStorage and clears it on sign-out; storage of access tokens has security trade-offs.

Client exports and analytics

The UI generates CSV and clipboard text locally. Searches are written to Cloud Firestore with username, time, optional account ID and browser/referrer fields.

Handle large GitHub lists

Problem: GitHub returns follower data in pages instead of one complete response.

Solution: The API service requests successive 100-user pages and waits for both lists before comparing account names.

Compare two lists without nested loops

Problem: Looking up every account against every other account would do unnecessary work.

Solution: A Set of follower logins allows the following list to be checked in one pass.

Explain rate limit failures

Problem: Anonymous GitHub API calls have tighter limits and can fail after repeated searches.

Solution: The client recognizes rate limit responses, shows a specific error, and offers optional GitHub sign-in for authenticated requests.