Briefle words · Product & specs
Edge case
An unusual but possible situation or input at the limits of normal use, like empty, zero or very long values, that still has to work.
Say it to an AI
Draw the split-a-bill user flow: the happy path in four steps, and under each step the edge case that can break it (uneven split, friend not on the app, unpaid after 7 days, decline), with the rule for each.
How an expert would brief the stronger version of “User flow diagram”.
See it
Try it as a puzzle →A payments app maps the 'split a bill' flow before handing it to an AI coding tool to build.
Why: B's dashed boxes: an amount that won't divide evenly, a friend not on the app, a request unpaid for 7 days, a decline.
More ways experts use it
Acceptance criteria for gift card payment at checkout: one happy-path line, then the unhappy paths and edge cases: partial balance, expired code, zero balance, and brute-force guessing. Each criterion names the exact message or behavior.
Gift card at checkout · Product & specsWrite the courier-tipping user story with acceptance criteria about behavior, not UI: tipping window, allowed amounts, where the money goes, one tip per order, and the failed-payment edge case. Leave colors, layouts and animations to the design file.
Courier tip story card · Product & specs
Related words
Room 1 · Essentials
Learn “Edge case” in a five-minute lesson