gologin is a well-tested Go library that turns OAuth1 and OAuth2 authorization flows into chainable net/http handlers. In production it lets a web app register LoginHandler and CallbackHandler for providers (GitHub, Google, Facebook, Bitbucket, Twitter, Tumblr) and then read the authenticated user or access token from the request context in the success handler. It also provides a Twitter TokenHandler for native mobile token login. The architecture is a set of primitive handlers (state, login, callback) that communicate via context, with provider packages composing those primitives and adding a user-fetching step; session management stays orthogonal to authentication. The oauth2 subpackage implements RFC 6749 state-parameter CSRF protection with short-lived secure cookies, while the oauth1 subpackage splits request-token acquisition, auth redirect, temporary-secret persistence, and access-token callback so providers with different secret requirements reuse the same pieces. Provider packages are intentionally thin wrappers around the generic handlers and call provider APIs (go-github, go-twitter, sling, google.golang.org/api) to fetch User objects. The code is thoroughly unit-tested with httptest mocks and includes runnable examples for GitHub, Google, and Twitter. Maintenance is active and the dependency manifests are current, though a few provider endpoints lag behind platform APIs (Facebook still targets Graph API v2.9 and Twitter targets v1.1 verify_credentials), so those specific integrations may need updates. The generic OAuth1/OAuth2 machinery remains solid and portable.