Flexible Authentication: Reimagining authentication for millions of users at Airbnb

Rebuilding login and signup surfaced product insights, not just technical challenges. Here’s how we designed Flexible Authentication at the intersection of product intuition and technical architecture.

By: Jose Santos, Mike Barry

For Airbnb, logins at irregular intervals are normal. A guest books a trip in January and may not open the app again until summer. A host checks back only when a reservation comes in, and may be busy with other activities when it does. For a two-sided marketplace where a failed login means a lost booking, and lost revenue for both the guest and the host, long gaps between sessions are a structural challenge, not an edge case.