Code review
Another engineer reading changes before they ship, or an outside party reviewing a whole codebase, to catch bugs, risks and shortcuts.
Updated October 2026 · with examples from our own builds
What does code review mean in practice?
Code review happens at two scales. Day to day, each change is read by a second engineer before it merges. Occasionally a client or investor commissions a review of the whole codebase, which produces a list of findings with severities.
An outside review is a health check and a negotiation tool. The useful response is neither defensive nor blanket agreement: each claim checked against the code, a verdict and a time to close. Some findings will be new features in disguise and deserve their own estimate.
Reviews find what tests miss: a security check that is wired up but never runs, a rule applied in the wrong place, a seed value nobody questioned.
Code review at a glance
- Two scales
- Per change, and whole-codebase reviews
- Good response
- Each finding checked, with a verdict and a time to close
- Finds what tests miss
- Checks that are wired up but never run
Where has code review come up in our builds?
In July 2026 Trainr shared a source-level review with 27 claims in four severity bands. We checked every claim at the exact file and line it cited, answered each with a verdict and a time to close, and reported a defect the review had missed.
A review of our own code found that the fresh-2FA check on break-glass grants had been mounted as the middleware factory instead of being called, which silently skipped it. It is fixed, with a comment at the route explaining why.
Our own reviews caught mistakes the tests missed, such as a seeded final price three times its quote that 46 passing assertions had not questioned.
Common questions about code review
Should I commission an independent code review?
Before a handover, an investment or a major rebuild, it's worth it. Ask for findings with file and line references and severities, so the response can check each one.
How should a team respond to a critical code review?
Claim by claim: check each one at the line cited, give a verdict and a time to close, and separate real defects from new feature requests. Dismissing nothing without a code-level check keeps the conversation factual.
Related terms
Sources
Planning a product and not sure where code review fits? Ask us, or browse all 116 terms in the glossary.