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Githubs performance has been rapidly degrading ever since they started rewriting everything in React.

It's basically impossible to view diffs now because they often fail to load, render correctly, or just are incredibly slow.

Yes this shift to React is really annoying. Github also stopped working on older browsers.

My leisure laptop is an older macbook with firefox 78.15.0esr and a little over a year ago I stopped being able to view github files and issue discussions with it. I can still view READMEs most of the time but now I have to use chromium or another computer to actually read code without cloning the repo.

I know they could easily generate JS for older browsers if they cared to set the esbuild target.

Everything has been getting worse since the React rewrite(s). Everything is just so much more slower and janky. And things like the "back button" keep acting weird (I reported this several times, after a long delay they fixed it several times, and it just keeps breaking a few weeks later – I've given up).

Some of the design decisions are also just baffling, like having "New Issue" in a small modal instead of just a full-screen page (only if you have templates set for some reason). Having less than half the screen being used is not helpful, and only going to reduce the quality of reported issues because it's just shit UX. Baffling. I genuinely wonder if the people designing/building this have ever used GitHub themselves (they reverted some of the other misguided "how on earth did you think that was a good idea?!" features, but not this one).

I have so many more gripes and bugs; clicking "show raw" generally works better for viewing code (or just cloning locally). It's just embarrassing. But it's all pointless to report because nothing gets fixed and it all just keeps getting worse.

GitLab was a "GitHub clone", but I guess now GitHub is turning in a "GitLab clone" by making everything a slow janky barely working mess.

I was baffled by the technical blog post they published on this subject, in 2023: https://github.blog/engineering/architecture-optimization/cr...

They completely redesigned the code navigation to load it dynamically using React. One of the regressions introduced caused the entries to be duplicated when searching for a word using Ctrl+F. Their solution to address this issue? Decompose the source character by character, assigning each individual character its own distinct HTML node...

Needless to say, in addition to abysmal performance (it took seconds to display on my laptop), this also caused new problems (such as the inability to search for certain composite emojis). The worst part is that they seemed proud of their hack, since they wrote a blog post about it.

I don't know any of the background but the diff viewer is near unusable past around 5k lines of diff on my M1 Mac.
I particularly appreciate when the diff is the addition of a new file and it still takes forever to compute a diff or whatever it’s doing behind the scenes.
There was a video recently talking about this with a good visualization [0]

The root cause of the problem is very fundamental to React and the nature of how the team designed the reactivity model. The TL;DR: React has an inverted model of state management [1].

In Vanilla, Vue, Svelte, Solid, any signals-based reactivity model, you explicitly opt-in to state changes by moving code into your reactive callback. In fact, in almost all of the code that you write, you typically explicitly opt-in to changes in state.

In React, you explicitly opt-out of state changes by moving code out of the reactive callback because the entire component function is the reactive callback (so any state in the path of that function that should not trigger a re-render has to be moved out via a hook).

This fundamental difference is what makes React hard to do well at scale because one needs to be very cognizant of where to place state inside a component and how to optimize for performance with memoization [2] (something Vue and Svelte developers pretty much never think about). The React team spent 2 years building the compiler to automatically manage memoization, but from the benchmarks I've seen, it's hardly made a difference.

In that time frame, Vue has been working on "Vapor Mode" [3] which bypasses the VDOM and brings it to parity with Svelte, Solid, and very close to Vanilla while still retaining a very easy to grok model of reactivity.

[0] https://youtu.be/INLq9RPAYUw

[1] https://chrlschn.dev/blog/2025/01/the-inverted-reactivity-mo...

[2] https://tkdodo.eu/blog/the-uphill-battle-of-memoization, https://tkdodo.eu/blog/the-useless-use-callback

[3] https://www.vuemastery.com/blog/the-future-of-vue-vapor-mode...

Were they using vanilla js? That's impressive if yes.
Even tech influencers who love React, like Theo Browne, has heavily criticise how bad is made GitHub in that regard.

IIRC they set the diff page to update entirely every reactive element in the page when some of this element change, instead of that one.

I wonder if it's React. The GitHub app takes between 3 and 4 seconds to refresh the notifications, and I only have about 20 in my list.
It's very obvious that they've unleashed a bunch of very junior developers on front end, it's I'm surprised that it still works.

The previous AJAXed implementation had its haters, but at least it was very close to bare HTML on HTTP.

It's also getting a lot flakier. Around October or November of last year I realized that every week I see another bit of SPA jankiness. I lose my scroll position because some component has appeared or disappeared above view. The issues list shows hours-old state and does not refresh. A button doesn't work. A page loads but everything below the header is unstyled. I expand the build details but it collapses closed every time a stage finishes. A filename header appears twice. New comments don't appear. On and on.

It's very frustrating to have a tool that has spent 15 years fading into the background of reliable infrastructure become an intrusive, distracting mess.

After a couple months with jujutsu it's almost completely replaced my use of git. It’s a lot to hope for, but just as jujutsu surveyed a couple decades of VCS to syncretize a huge improvement, I do hope someone will do the same for collaborating with jujutsu. GitHub PRs feel very unfortunately frozen in amber because their popularity makes it very hard to fix the core UI design problems it has with multiple tabs, incoherent timeline, edited commits, missing "8 more comments", and now a steady drip of SPA jank.

The big remaining feature of GitHub is the network effect of coworkers and potential contributors already being logged in, and there could be a race between a competitor neutralizing that with bidirectional sync (see git-bug) and GitHub getting their usability problems sorted. Microsoft's legendary resistance to breaking changes means there's a very big window available.

I’m glad to see my feelings validated. I’m always grumpy about some good, functional software being made worse because there is a big engineering org who has to work on something so they change things and it results in degradation of the software.

I’ve been noticing GitHub’s UI getting sluggish and thought that maybe I’m off my rocker or it was a “my machine” problem, because Github wouldn’t do that… but I guess it’s pretty damn hard to prevent a bunch of devs, managers, and PMs from making changes to prove they should still be employed.

I suffer it and that’s why I’m building https://githero.app

Btw, I worked at GitHub for 3 years and they are very aware that slowness is a big issue throughout the whole product. There was a year long cross team effort to improve things but the main goals were not achieved IMO and it shows.

As an interesting example of the opposite UI experience, this video goes into why the McMaster-Carr website is so incredibly snappy to use: https://youtu.be/-Ln-8QM8KhQ.

It's different from GitHub in many ways (no user-generated content, day-by-day mostly static pages), but it's interesting to see how good a browsing experience can be. It makes sense given that their value as a company depends so much on making it quick and easy to find exactly what you need.

It feels very similar to Facebook UIs and everything under FB for Business (managing ads, Instagram comments, etc). Definitely because of React and the amount of client side rendering logic in general.

Which is crazy given how little interactivity and DOM state a site like GitHub actually needs to manage.

The code viewer is completely unusable for any file longer than a hundred lines. I have to clone it and browse locally instead.

It's been like this for at least a year. Does nobody at GH actually use their own website?

Have you used any other Microsoft web services? They’re all slow and terrible
Using the symbol explorer (or whatever it’s called) on files is nice for following definitions through files, but it makes the browser back button completely non-functional. Often the URL will actually change to the previous history state, but the page content never changes. Trying to then reload with the changed URL also doesn’t work for whatever reason.

It would be a really great feature if it worked correctly.

It degraded so much, I remembered how the UX used to be so enjoyable. Now, a forgejo instance hosted on an old raspberry pi at home is where my projects live, and it is fast and snappy in comparison.
GitHub, Facebook, Reddit, Instagram (on the web)... All these major websites are becoming incredibly hard to use. My intuition would be "SPA crap" but I'm pretty sure you can make great and snappy SPAs. What am I missing?
I made a competitor to GitHubs UI for Pull Requests (codeapprove.com)

It’s built in Vue. My first 5 or 6 attempts at writing the diff viewer were very slow when things got big. I optimized this a lot and now I’m pretty proud of how snappy it is.

I’m not saying this as a plug (this is mostly a passion project not a big business) but to say that it’s possible to make a snappy GitHub PR UI using a frontend framework on top of GitHub’s own APIs. You just have to care. It’s not clear that they care.

Revert GitHub to any commit from 2012. Just have code, PRs, issues, fast and reliable. Rip everything else out and cast it into the sea. I would pay more for this product.
We should make a cultural norm to keep old interface running when rewriting projects start. Just like https://old.reddit.com/ is still chugging.

At least as reference for rewrite developers to remind what that should strive to outperform.

I'm building a new Git hosting service, focused on performance and using HTMX. For example, compare page load time:

- https://gitpatch.com/gitpatch/git-demo

- https://github.com/git/git

Related ongoing thread (i.e. since the OP is a few months old, I assume it was posted in connection with):

GitHub pull requests were down - https://news.ycombinator.com/item?id=44799494 - Aug 2025 (113 comments)

I still maintain that building web frontend using classical server side template + progressive enhancement in JS is superior.

Too bad that everything has to be rewritten in React.

wow, every web ui is going to shit after a decade of cargo culting SPAs and shiny completely unnecessary frameworks! no one could have possibly saw this coming.
Reminds me of a discussion that Casey Muratori and Robert Martin had over clean code and it's impact on performance... but not because of the subject matter. They were using GitHub as a medium for their discussion, and they ran into some serious lag when typing paragraphs into just the hundreds of characters (ctrl+f emoji, ~1/4 of the way through):

https://github.com/unclebob/cmuratori-discussion/blob/main/c...

Definitely immediately noticed slowdown after the sidebar and other updates. I thought surely they would fix it quickly but no... And now it seems like the only way they support to browse!
If you just need a place to store your code, self-hosted Gitea is very easy.

Your discoverability will drop to close to zero, and Actions are trickier to set up. Plus, you'll have to come up with a backup plan.

But, you'll be hosting your code on your machine, Microsoft will be out of the loop completely, and you won't be feeding the AI monsters if your repo's are set to "private".

Slower and broken more often, a winning combination!
Yes, even at the point where some items fail to render with proper style and the buttons don't work. I wish there were a GitHub frontend that used more basic HTML for it to work on older browsers and lower network speeds.
Can’t they use their AI to rewrite the entire thing to be faster?
> You guys developing at GitHub, you're using GitHub to develop it, right?

They could be using an internal beta version so they can "eat their own dogfood" before shipping.

Funny to see GitHub still on the path to React, while Edge is already migrating to web components, due to performance issues related to React.
I'm so glad someone documented this. it's been driving me crazy. I was just in a serious crunch mode for a couple of week, so all kinds of minor speed bumps in my workflow have become really evident to me. The UI transition between PR "tabs" has been one of the worst.
The website is crashing constantly on me. I just assumed it's Microsoft doing their typical thing.
Interestingly enough, the iOS app has been working really well for me.

Performance, usability and overall adaptability to the phone size, it is incredible how a native app can be that good.

I wish the Web UI performed as well as the native iOS app.

There is a whole new paradigm in UX design now: get rid of immediate page changes and loading states and instead keep the user on the same page until things load, and show it when it's ready.
My PC hangs as soon as any "dynamic" javascript button starts to load! I'm glad I was not the only one, finally!
I always wondered why back button in iOS is not working on github, this broken client side routing makes no sense
Obviously if you use any kind of javascript on such website things go to hell. Git solutions are Forgejo are running circles around gitlab and github, it renders everything insanely fast.

Disappointing devs still try to justify javascript on large sites like git.

Once a company achieves market dominance the only thing left to force a focus on users is its management.
it felt like DNS was broken at some points because the page just wouldn't load, and sometimes just the navigation bar would load, but no content -- is this what you're talking about ?
Incredibly well timed given today's outage
Ooh ooh I know this one! Because its Microsoft!
i've noticed viewing diffs to be a painpoint, doesn't load the entire thing.