Our view: nobody can honestly promise zero bugs. What you can do is make checking a written, repeatable process that grows every time something goes wrong.

What we check before handover

• The screens work at phone, tablet and desktop sizes.
• We test with real data, not sample data.
• We run a list of known, recurring mistakes: boxes that do not line up, buttons hidden behind a bar, text that jumps while loading.
• Anything that reaches a customer needs a person's approval first.
• We test the whole path from start to finish, not only the parts.

What still slips through

We have handed over systems that still had bugs. We have also handed over systems that did not match what the customer expected. These are two different problems.

Bugs are fixed by better checks. Gaps in expectation are fixed by a clearer agreement at the start: show what will be built, and label honestly what is Live, a Demo, Built or only a Mockup.

How we respond

Every bug becomes one more line in the written checklist, so the same bug cannot come back. Our aim is for the checks to be run by a reviewer that did not build the system, so the builder is not marking its own work. We are not there yet for every system.

Three questions to ask any vendor

• Is the delivery checklist written down, and can I see it?
• What happens when you find a bug after handover?
• Does the person who built it also check it?