SSO Tracer

Trace and decode OAuth 2.0, OIDC and SAML 2.0 sign-in flows in a DevTools panel. Local only, nothing leaves the browser.

SSO Tracer is a DevTools panel for debugging single sign-on. It watches OAuth 2.0, OIDC and SAML 2.0 traffic as you authenticate and shows you the decoded flow — not a wall of raw network rows. WHO IT IS FOR Identity engineers, backend developers and security testers who have to answer "why did this login fail?" against a real deployment: an IdP on one domain, an SP on another, and a handshake between them that nobody can see. Chrome's Network tab shows you base64 and query strings. This shows you the flow. WHAT IT CAPTURES • OAuth 2.0 — authorization requests (including PKCE), code and implicit-token callbacks, token exchanges, and RFC 6749 error responses • OIDC — ID tokens with every claim labelled and expiry computed, discovery documents, end-session/logout • SAML 2.0 — AuthnRequest and Response over both the POST and HTTP-Redirect bindings, assertions, attribute statements, conditions and status codes • Token introspection — RFC 7662 requests and their active/scope/exp responses WHO IT IS FOR Identity engineers, backend developers and security testers who have to answer "why did this login fail?" against a real deployment: an IdP on one domain, an SP on another, and a handshake between them that nobody can see. Chrome's Network tab shows you base64 and query strings. This shows you the flow. WHAT IT CAPTURES • OAuth 2.0 — authorization requests (including PKCE), code and implicit-tanges, and RFC 6749 error responses request, code callback and token exchange are linked by the state parameter, so one click surfaces the whole chain instead of you scrolling a network log looking for the other half. • It finds tokens other tools miss. Most tools look for a URL ending in /token returning {access_token, id_token}. Real deployments do not cooperate. SSO Tracer scans JSON response bodies for JWT-shaped values under any key name at any URL, so a custom endpoint answering {"jwt": "eyJ..."} is picked up like any other token response. • Manual decoder — paste a JWT, an OAuth redirect URL, or a SAML message in any binding (raw XML, POST base64, or Redirect deflate) and read it decoded. No captured traffic needed. • Expiry and signature metadata at a glance — alg, kid, and whether the token is valid, expiring or already expired. PRIVACY Everything stays in the browser. The extension makes no network requests of its own: no fetch, no XMLHttpRequest, no WebSocket, no analytics, no account, no backend. Captured events live in memory-backed session storage and are gone when you close the browser. Exports are redacted by default — tokens, authorization codes, assertions and PII claims are replaced before the file is written, and turning that off requires confirming a dialog that spells out what the file will contain. HOW TO USE IT 1. Open DevTools (F12) and select the "SSO Tracer" tab. 2. Open it BEFORE you sign in — request and response bodies are only readan. 3. Perform the login. Events appear live; click one to inspect it.