They started with Ink but have since switched to their own renderer:
> We originally built Claude Code on Ink, a React renderer for the terminal. [...] Over the past few months, we've rewritten our rendering system from scratch (while still using React).
React is just an abstraction of a State -> View function.
While not universally applicable, it's very convenient during development to focus on State without thinking about View, or focus on View without thinking about State.
The concept itself has nothing to do with the actual renderer: HTML, TUI, or whatever. You can render your state to a text file if you want to.
So the flickering is caused either by a faulty renderer, or by using a render target (terminal) that is incompatible with the UI behavior (frequent partial re-renders, outputting a lot of text etc.)
Thats the problem. Some developers want to avoid learning another programming language and use one for everything (including their technologies.)
Using TS, React here doesn’t make sense for stability in the long term. As you can see, even when they replaced Ink and built their own, the problem still exists.
There are other alternatives that are better than whatever Anthropic did such as Bubbletea (Go) or Ratatui (Rust) which both are better suited for this.
Maybe they were thinking more about job security with TypeScript over technical correctness and a robust implementation architecture and this shows the lack of it.
I’m a fan of Bubbletea, but it is significantly less ergonomic than React. Although I’d argue that if that starts to matter significantly, your TUI is probably too cluttered anyway and you should pare it down.
> We originally built Claude Code on Ink, a React renderer for the terminal. [...] Over the past few months, we've rewritten our rendering system from scratch (while still using React).
https://github.com/anthropics/claude-code/issues/769#issueco...