Show HN: Codiff, a local diff review tool

[cpojer]

Nowadays I review a lot of code locally that was written by llms. I used to review my own code using git + delta. It started to feel limiting with the amount of code written by llms.

When looking at a large diff on Friday I pointed an llm at diffs.com and trees.software and told it to build an app. It only took 16 minutes, is extremely fast for large diffs, beautiful and minimal.

Today I polished it up and added all the features that I need. It has file filters, search, an llm walkthrough mode, and review comments that you can paste back into your llm.

I will be using Codiff a lot, and can finally review the large diff from Friday that led me to build this If you like it, fork it!

[magnio]

Is diff viewer the 2026 todo list?

List of vibe coded alternatives:

- revdiff: https://github.com/umputun/revdiff

- hunk: https://github.com/modem-dev/hunk

- diffnav: https://github.com/dlvhdr/diffnav

- diffx: https://github.com/wong2/diffx

- lumen: https://github.com/jnsahaj/lumen

[cpojer]

4 of these are TUIs. I built Codiff specifically because TUI review became overwhelming to me. One of them is a web view, I prefer a native app window (it’s JS either way, ofc).

Also, I never wasted time building todo apps. Now I can build apps that help me do my job that I wouldn’t have had the time for without AI.

[bestouff]

Kids these days. Calling JS "native" makes my stomach ache, but apparently this is normal.

[cpojer]

1. I’m older than you. 2. I said native app window, comparing it to a tool with a browser web ui.

[bestouff]

1. Why are you saying that ? Looking at your LinkedIn I'd say you're in your 40s, so effectively younger, lucky you !

2. Still, JS in the app window is not what I call native, but I won't fight over this

[cpojer]

1. I am not in my 40s, but I take it that I was wrong ;)

[realrocker]

:) We are all converging on the same problems and tooling to fix them.

Built this in the last couple days to review changes done by claude on a hetzner box(over tailscale on my phone) and leave comments before pushing to remote : https://github.com/livetemplate/prereview.

Runs everywhere and can has a claude skill: /prereview which starts a new instance for the current changes. Has a “Hand-off” button to signal claude to process the comments.

UI is responsive. I use it on my iphone with claude mobile app + /remote-control to leave comments before pushing.Still requires polish but core features work.

[cpojer]

That’s awesome! I built this specifically as a GUI because it’s become too much code to effectively review in the terminal for me.

[realrocker]

exactly. LLM code output is so high that it has become unreasonable to review the code in terminal or ide

[Evan-Purkhiser]

Would love to see some screenshots in your readme of this!

[realrocker]

Yeah the project is right out of the oven so will add some usage gifs shortly to the repo. Meanwhile here are some screenshots on imgur: https://imgur.com/a/zxZo651

[stephenr]

Who knew that the killer task for LLMs would be "recreate existing things that exist without me mentioning them by name, based on a worse alternative as the example".

Kaleidoscope exists.

File Merge exists.

[cpojer]

Codiff is faster and scales to larger commits than those.

[stephenr]

You're seriously suggesting that an electron app you vibe coded in two days is more performant than native code that's been developed and improved and tweaked over literal decades?

[cpojer]

Yes. It’s built on diffs.com and trees.software.

[d3xt0r123]

there's a small directory tracking these — vibcod.dev. free to submit, each listing shows stack, models used, and a vibe-index score.

[sjhalani7]

That's awesome. Been reviewing code diffs on the IDE and it's been hard, so will check this out!

[tcoff91]

Can you include screenshots in your readme?

Also does it only work for staging and unstaged changes? I use jj so I need to be able to point it at commits since jj has no staging it just creates a new git commit snapshot every time you run any jj command.

[cpojer]

There is a screenshot in the README.

There is a video here: https://x.com/cnakazawa/status/2055881241677668637?s=46&t=BS...

It works for any staged, unstaged or untracked file in a repo. It does not have support for mutations (like staging or unstaging a change) yet. It does not yet work for specific commits but should be super easy to add.

[usernametaken29]

Surprisingly enough this has just a few features the JetBrains diff view is lacking, notably file search… good ideas

[atmanactive]

... for MacOS.