UI review for engineers

You already review diffs. Agent PRs and human PRs that touch UI still leave a gap: the code can look right while the running product fails a real path. Diffraction is private MVP / design-partner ready UI review (product experience review) for UI-affecting GitHub PRs on web apps. It is aimed at showing what the PR head actually does, with aberrations backed by evidence. Tagline: See the full spectrum of every diff.

Aberration (eng framing): An aberration is a verified product-experience failure found while reviewing a running UI: something a user would hit that a clean diff and green checks did not catch.

PR head as product: Reviewing the PR head means experiencing the running change, not only reading the patch or trusting a preview glance.

UI-affecting PRs are noisy. Some are yours. Some come from teammates. More arrive from agents that produce plausible diffs at high volume.

What usually happens:

• You read the diff and comment on structure
• Checks are green
• Maybe you open a preview, click once, merge
• The failure lives in a flow, default, empty state, or mobile path you did not exercise

Source-only PR bots help with code-shaped review. They do not experience the product. Pixel baselines help with unintended visual drift. They can pass while the path is wrong. You still own the merge button.

Visual breakage can be one aberration. So can a path that looks fine and cannot complete the job. Diffraction's category is product experience review, not screenshot diffing. Contrast: UI review vs visual testing.

Thesis: source correctness ≠ product correctness.

For design partners, Diffraction is built to exercise the running PR head and return verified aberrations with evidence.

What that gives you day to day:

• A clearer overview of UI-affecting PRs (agent or human) before you merge
• Concrete findings: repro path and evidence, not approval from a screenshot
• A way to catch product failures you would only find after merge when the blast radius is real
• Less reliance on a single preview click-through

You still write and review code. Diffraction is aimed at the layer above source: does this change still work as a product?

Category: What is UI review?. Terms: Glossary.

Stay in GitHub. Treat UI-affecting PRs as needing product truth, not only diff truth.

1. A PR changes UI, flows, or product behaviour on a web app.
2. Diffraction (private MVP, design-partner scoped) reviews the PR head as a running experience.
3. Aberrations land with evidence you can inspect.
4. You fix, dispute, or accept with the same artifact reviewers and QA can see.
5. Merge with fewer production-later bets on UI paths.

Useful when agent volume is up and human attention per PR is down. The point is not more ceremony. It is a better signal on the PRs that actually change what users touch.

Stories that make the thesis concrete (link titles only):

Three checkboxes almost cost a billion dollars

Six people and a national signup flow

The button costing $300 million a year

Other roles: executives, designers and QA, and engineering leads.

If you ship web apps on GitHub and want early design-partner access to a private MVP, email hello@diffraction.sh.

Say how UI-affecting PRs get reviewed today (including agent PRs if that is your world). Design-partner interest is welcome.

See the full spectrum of every diff.