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I made a heatmap diff viewer for code reviews

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0github.com is a pull request viewer that color-codes every diff line/token by how much human attention it probably needs. Unlike PR-review bots, we try to flag not just by "is it a bug?" but by "is it worth a second look?" (examples: hard-coded secret, weird crypto mode, gnarly logic, ugly code).To try it, replace github.com with 0github.com in any pull-request URL. Under the hood, we split the PR into individual files, and for each file, we ask an LLM to annotate each line with a data structure that we parse into a colored heatmap.Examples:https://0github.com/manaflow-ai/cmux/pull/666https://0github.com/stack-auth/stack-auth/pull/988https://0github.com/tinygrad/tinygrad/pull/12995https://0github.com/simonw/datasette/pull/2548Notice how all the example links have a 0 prepended before github.com. This navigates you to our custom diff viewer where we handle the same URL path parameters as github.com. Darker yellows indicate that an area might require more investigation. Hover on the highlights to see the LLM's explanation. There's also a slider on the top left to adjust the "should review" threshold.Repo (MIT license): https://github.com/manaflow-ai/cmux

HN · launched Oct 30, 2025 · 265 upvotes (top 2%) · 0 views

Niche: code diff and technical document viewers · 26 launches, 0 in the last 7 days · Explore this niche →

Category and tags

  • Horizontal
  • Dev tools
  • Developer
  • Not AI
  • Hobby / open-source project

Visit website ↗ Source listing ↗

Could you build this?

Yes A web-based diff viewer integrating with GitHub PRs that applies static rules or an LLM call to color-code attention hotspots can be vibe-coded in days.

Discussion

20 comments analyzed.

Competitors mentioned: Claude Code for code review and understanding, GitHub's native code review tools

Concerns raised: Excessive energy consumption and climate impact for minimal utility, Inaccurate highlighting - misses important deletions and deleted code, Highlights test code over material changes needing review, Highlights unchanged lines incorrectly, LLM lacks context for familiar codebases - reviewers know code better

Feature requests: Dark theme with prefers-color-scheme: dark support, Remove GitHub sign-in requirement for local repository support, CLI-only version for easier integration, Respect inline comments explaining deprecations or intentional choices, Better support for understanding deleted code and removals

Competitors

Other products that read as similar to this one : 155 launches clear the similarity bar, closest 8 shown.

Attention rank: #5 of 156 (itself plus its competitors, highest first, normalized so YC and Product Hunt are compared fairly).

Looks like the first mover among its competitors.

  • Diffswarm · hn · 2026-01-06 · 8 upvotes · similarity 0.55
  • MyGitDiff · github · 2026-09-10 · 7 upvotes · similarity 0.48
  • DiffCue · ph · 2026-10-15 · 2 upvotes · similarity 0.47
  • CodeSloth · ph · 2026-11-01 · 2 upvotes · similarity 0.45
  • Stacked PRs for GitHub · ph · 2026-10-16 · 1 upvotes · similarity 0.45
  • peek · github · 2026-10-24 · 66 upvotes · similarity 0.44
  • Haystack · hn · 2026-05-18 · 45 upvotes · similarity 0.43
  • GitReview · ph · 2026-11-01 · 2 upvotes · similarity 0.43

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