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Why ztui

Most TUI toolkits sit at one of two extremes.

Some are too primitive — raw ANSI, or thin wrappers where you hand-roll layout, focus, scrolling, and every widget yourself. You spend your time rebuilding a UI toolkit instead of building your app.

Others chase maximal performance with native render backends. They’re fast, but hard to see into: the UI exists only as bytes painted to a terminal, so debugging is print-statements-and-squinting, and there’s nothing concrete for a test to assert on.

The bet ztui makes

Section titled “The bet ztui makes”

On a modern machine, a TUI paints a few thousand cells per frame. Raw render throughput is rarely what’s slow — iteration speed and debuggability are.

That’s truer than ever now that so much code is written and maintained by LLMs and agents, which can’t sit and watch a terminal scroll by. An agent (or your CI) needs to read the current screen and act on it programmatically. A native byte-stream backend gives it nothing to grab onto.

So ztui optimizes for a model you — and an agent — can reason about, test, and operate:

  • A familiar mental model. One declarative React tree, hooks and all. No bespoke layout DSL to learn.
  • Everything serializes. The widget DOM and the rendered frame export to JSON, HTML, and plain text — see Architecture.
  • Headless and inspectable. Headless drivers and a REST inspector let humans, CI, and agents see and assert on the UI with no real terminal — see Debugging & AI agents.

An honest take on performance

Section titled “An honest take on performance”

This is not “slow but debuggable.” ztui stays performance-conscious — ANSI cell diffing so only changed cells repaint, list/table virtualization for huge data, synchronized output to avoid tearing, and lazy/native graphics. For the tools, dashboards, and agent UIs it targets, it’s fast.

What it deliberately does is trade a sliver of raw native throughput for a framework that’s legible end-to-end. The honest guidance:

  • Building a 60fps fullscreen game or a million-row live render in the terminal? A native engine (Rust/C) will beat it on raw frames-per-second.
  • Building tools, dashboards, dev experiences, or agent-operated UIs — and want them testable and AI-operable? That’s the gap ztui fills.

If debuggability and a real component model are worth more to you than the last few percent of render throughput — especially with agents in the loop — ztui is built for exactly that trade.