---
title: Installation
description: Install Prefab and pin to a stable version.
icon: arrow-down-to-line
---

## Install Prefab

We recommend using [uv](https://docs.astral.sh/uv/getting-started/installation/) to install and manage Prefab.

```bash
uv add prefab-ui
```

Or with pip:

```bash
pip install prefab-ui
```

Prefab requires Python 3.10+.

### Verify Installation

```bash
prefab version
```

## Versioning Policy

Prefab is pre-1.0 software under **extremely** active development. The API surface is evolving quickly — components get added, renamed, and reworked as the project discovers what patterns work best for building agent-native UIs.

### What This Means in Practice

**Minor versions (0.x.0) may include breaking changes.** Prefab follows semantic versioning with the standard pre-1.0 caveat: while the major version is `0`, any minor version bump can change the public API. A bump from `0.5.0` to `0.6.0` might rename components, change default behaviors, or restructure modules.

**Patch versions (0.0.x) are safe updates.** Patch releases contain only bug fixes without breaking changes.

### Pin Your Version

For any use beyond experimentation, pin to an exact version:

```
prefab-ui==0.5.0  # Good
prefab-ui>=0.5.0  # Bad — may install breaking changes
```

Or pin to a minor range if you want patch fixes:

```
prefab-ui>=0.5,<0.6  # OK — gets patches, not breaking changes
```

### Breaking Change Philosophy

Prefab is young, and that means being willing to fix API mistakes early rather than carrying them forever. Each breaking change is a deliberate decision to keep the framework simple and consistent rather than accumulating design debt.

When breaking changes occur:
- They only happen in minor versions (e.g., 0.5.x to 0.6.0)
- Release notes explain what changed and how to migrate
- Changes must substantially benefit users to justify disruption

### Public API

The public API — what's covered by compatibility guarantees within a minor version — consists of:
- All classes exported from `prefab_ui.components` and `prefab_ui.actions`
- `PrefabApp` and related app-level utilities
- The `prefab` CLI commands
- The JSON wire protocol schema

Everything else (internal modules, private methods, renderer internals) may change without notice.

Pin your dependencies and check release notes before upgrading.
