Our fix to remove flickering is rolled out again to everyone on...
Thariq@trq212
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Jan 24, 2026
~2 min read
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Our fix to remove flickering is rolled out again to everyone on Claude Code.
Why did we roll it back? If Claude is so good, why were there bugs to begin with? Why was it so complex? 🧵
Why did we roll it back? If Claude is so good, why were there bugs to begin with? Why was it so complex? 🧵
Thariq is on vacation@trq212
We’ve rewritten Claude Code’s terminal rendering system to reduce flickering by roughly 85%.
We wanted to share more about why this was so difficult, how the fix works and how we used Claude Code to fix it 🧵
We wanted to share more about why this was so difficult, how the fix works and how we used Claude Code to fix it 🧵
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Most people's mental model of Claude Code is that "it's just a TUI" but it should really be closer to "a small game engine".
For each frame our pipeline constructs a scene graph with React then
-> layouts elements
-> rasterizes them to a 2d screen
-> diffs that against the previous screen
-> finally uses the diff to generate ANSI sequences to draw
We have a ~16ms frame budget so we have roughly ~5ms to go from the React scene graph to ANSI written.
For each frame our pipeline constructs a scene graph with React then
-> layouts elements
-> rasterizes them to a 2d screen
-> diffs that against the previous screen
-> finally uses the diff to generate ANSI sequences to draw
We have a ~16ms frame budget so we have roughly ~5ms to go from the React scene graph to ANSI written.
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While we test Claude Code rigorously, our users run Claude in a huge combination of terminal and operating system setups.
Here we found that in some setups we were triggering Garbage Collection too often in our rendering pipeline.
Somethings you can't find until you ship.
Here we found that in some setups we were triggering Garbage Collection too often in our rendering pipeline.
Somethings you can't find until you ship.
4
This was a legacy migration, we had to port our entire rendering engine while making sure nothing user-facing broke.
Doing this without Claude Code could have taken on the order of 1-2 years for a single engineer, something we would have never been able to prioritize.
Doing this without Claude Code could have taken on the order of 1-2 years for a single engineer, something we would have never been able to prioritize.
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Wanted to clarify this 1-2 years thing. Of course this was just a back of the envelope estimate, it's entirely possible it's wrong.
And Claude Code itself is like a year old, so how could this take longer?
As a team and company grows, your codebase moves under you more often, coordination cost is higher and you have more users in more diverse scenarios so it is easier to break things. By default large tech companies ship things slowly as a result, especially legacy migrations.
Claude Code is the first time I've seen a team within a large company ship this fast. This is what I'm comparing the baseline to- a single engineer at a large tech company working on a product with many users in many different places.
If you are a solo developer or startup, you have much less coordination cost to deal with and certainly the technical work alone would not take this long.
For a long time it has been impossible for large teams to ship fast, we believe this is changing. That's the point I wanted to make, apologies if it was garbled.
And Claude Code itself is like a year old, so how could this take longer?
As a team and company grows, your codebase moves under you more often, coordination cost is higher and you have more users in more diverse scenarios so it is easier to break things. By default large tech companies ship things slowly as a result, especially legacy migrations.
Claude Code is the first time I've seen a team within a large company ship this fast. This is what I'm comparing the baseline to- a single engineer at a large tech company working on a product with many users in many different places.
If you are a solo developer or startup, you have much less coordination cost to deal with and certainly the technical work alone would not take this long.
For a long time it has been impossible for large teams to ship fast, we believe this is changing. That's the point I wanted to make, apologies if it was garbled.
