A Lesson From Production: Why the Login Session Window Grew From Two Weeks to 90 Days

A cashier or employee who signs in once and keeps working for weeks without re-entering their password used to be surprised by a vague "login failed" message after some time, with no way to tell if it was a normal session expiry or a technical glitch. This lesson covers how the TtaKkaa team made that difference clear.

The problem: one error message for two different causes

The system was returning the same generic error whether the session had genuinely expired (the employee actually needs to sign in again), or there was a different technical issue that made the session renewal fail temporarily. This made it hard for the support team to tell whether the problem was on the user's end or the system's.

The fix: a longer window, and a clear message per case

The TtaKkaa team extended the window before a full re-login is needed from two weeks to 90 days, as long as the employee uses their account regularly (the session renews automatically in the background). At the same time, the error message was split into two clear cases: "Your session has expired, please sign in again" when the 90 days have genuinely passed, and a different message for any other technical issue — so both the employee and support know exactly how to handle each case.

Why the longer window makes sense

An employee using the same device daily shouldn't need to re-login every two weeks, and that was causing real friction at shops with low staff turnover and a fixed cashier device.

The numbers, honestly

The TtaKkaa team added tests confirming session renewal succeeds at day 30 (past the short initial window, but still inside the 90-day range), and fails with a clear message exactly past day 90 — so the behavior is predictable and tested, not guessed at.

If you use TtaKkaa daily

You won't need to sign in again frequently as long as you use your account regularly. Sign up at store.ttakka.store and try it yourself.