— RESOURCES

Notes from the audit trail

Real patterns from real bug reports — what we test, why it breaks, and how to catch it before your customers do.

All Checkout Mobile Automation Security Process Agencies

Testing Guest Checkout: Where Conversion Quietly Breaks

Guest checkout is where conversion quietly leaks. Duplicate emails, orphaned orders, and the account-merge trap are the cases we test on every audit. Here is the checklist.

QA Signals · 1 Sep 2026 · 5 min read

CHECKOUT

The Idempotency Test Every Payment Flow Needs

A slow network and an impatient user is all it takes to charge someone twice. Here is how we test that a payment flow is actually idempotent, plus the three failure modes we find most.

QA Signals · 9 Aug 2026 · 5 min read

CHECKOUT

Testing Payment Failures: The 12 Scenarios Most Teams Skip

Everyone tests the successful payment. Almost nobody tests the twelve ways it fails — declines, 3DS timeouts, double-clicks, expired sessions. This is the list we run on every audit.

QA Signals · 18 Jul 2026 · 5 min read

CHECKOUT

How to Test Discount Codes and Tax Together (The Bug That Creates Support Tickets)

The checkout says one number, the invoice says another. When discounts and tax apply in the wrong order, every affected order becomes a support ticket. Here's how we test for it.

QA Signals · 18 Jul 2026 · 5 min read

CHECKOUT

The Checkout Bug Pattern We Find in Almost Every Audit

Charge succeeds, order never gets created. We've flagged this exact bug in most of the checkouts we've audited - here's why it keeps happening and the three tests that expose it

QA Signals · 18 Jul 2026 · 5 min read