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Introduction

StdUI is a lightweight cross-platform UI engine that can be used with any programming language. It spawns as a child process and communicates with your application via newline-delimited JSON. By default it uses stdin/stdout, but Unix domain sockets and named pipes are also supported for cases where subprocess pipes are inconvenient.

warning

This project is experimental. Expect bugs, missing features, and breaking changes. The API is not stable and may change without deprecation.

How it works​

Your App (Go, Python, anything)
        │  JSON commands  →
        │  ← JSON events
        │  (stdin/stdout, Unix socket, or named pipe)
        ▼
   stdui binary (C++)
   ┌──────────────────────────────┐
   │  litehtml  — HTML/CSS layout │
   │  ImGui     — interactive     │
   │             widgets          │
   │  raylib    — window, audio   │
   └──────────────────────────────┘

StdUI uses a reduced subset of HTML/CSS (via litehtml) for layout and styling, and ImGui for interactive widgets — with no browser involved.

Features​

  • Cross-platform (Windows, macOS, Linux)
  • Language agnostic (communicates via stdin/stdout, Unix sockets, or named pipes)
  • Supports a reduced subset of HTML/CSS for layout and styling
  • Pane-based layout system
  • Interactive widgets: buttons, text/number/password inputs, checkboxes, sliders, progress bars, color picker
  • Native file/folder dialogs
  • File drop support
  • Sound playback
  • Clipboard text access
  • Notification toasts
  • ~5MB binary size

Quick start​

1. Download the binary​

Grab the latest release for your platform from GitHub Releases.

Alternatively, if you are using the Go SDK, EnsureBinary can download it automatically:

if err := stdui.EnsureBinary("", ""); err != nil {
    panic(err)
}

2. Spawn and connect​

Send a settings message immediately after spawning the process:

{"action":"settings","data":{"title":"My App","windowWidth":800,"windowHeight":600}}

Wait for the ready event before sending any further commands:

{"action":"ready"}

3. Render UI​

Push HTML with update-content:

{"action":"update-content","data":"<h1>Hello!</h1><ui-button text=\"Click me\" action=\"hello\"></ui-button>"}

4. React to events​

Read stdout line by line and parse the JSON events:

{"action":"button-clicked","data":{"action":"hello","text":"Click me","pane":"main"}}

Send a new update-content whenever your state changes. There is no incremental patching — replace the whole HTML string.