1Code – Open-Source Cursor-like UI for Claude Code

TL;DR

TL;DR: 1Code is an open-source desktop app that wraps Claude Code and Codex with a Cursor-like visual UI — diff previews, git worktree isolation, background cloud sandboxes, and a built-in git client — all on your own API keys.

What Is 1Code?

1Code (from 21st.dev) is an open-source orchestration layer for coding agents. It runs Claude Code and Codex — locally or in cloud sandboxes — inside a visual desktop shell that adds diff previews, git isolation, and session management. It is Apache-2.0 licensed and self-hostable.

The project’s stated goal is to give developers a Cursor-like UI for any coding agent, with full control over models and providers (BYOK) and no lock-in to a proprietary platform.

Source and Accuracy Notes

• Project page: 1code.dev ← verified via live redirect to GitHub
• Source repository: github.com/21st-dev/1code ← README read in full
• License: Apache License 2.0 (verified via LICENSE file in repository)
• Stars: 5,632 (GitHub API, 2026-07-19)
• GitHub topics: coding-agent, cursor, claude-code, codex, open-source

Core Features

Multi-Agent Support

Switch between Claude Code and Codex in the same app without changing workflow. The UI stays consistent regardless of which provider is active. Model selection is persistent across sessions.

Git Worktree Isolation

Each chat session runs inside its own Git worktree. This means the agent never touches your main branch — changes stay sandboxed until you explicitly merge. If a session goes wrong, you delete the worktree. No stashed changes, no accidental commits.

Background Cloud Sandboxes

Cloud sandboxes keep agents running when your laptop sleeps. The agent works in a remote environment and you check the results when you return. Useful for long refactors or tests that would otherwise time out.

Visual UI with Diff Previews

The desktop UI shows exactly what changes the agent is making in real-time — not just a final diff, but live tool execution (bash commands, file edits, web searches) as they happen. Rollback to any previous user message bubble.

Built-in Git Client

Stage, commit, push, and create PRs without leaving the app. Git activity badges appear directly on agent messages. Branch management and remote sync are first-class UI elements.

MCP & Plugin Marketplace

MCP server management is built in. The plugin marketplace exposes skills, slash commands, and tool extensions. You can also build and distribute your own custom sub-agents.

Voice Input, Plan Mode, Chat Forking

• Voice input: hold-to-talk dictation
• Plan mode: agent asks clarifying questions and shows a structured markdown plan before executing — you approve before anything runs
• Chat forking: branch a sub-chat from any assistant message to explore alternative approaches
• Extended thinking: enabled by default with visual UX

Setup

Prerequisites

• macOS, Windows, or Linux
• API keys for Claude (Anthropic) and/or OpenAI Codex
• Git installed locally

Download and Install

# Download the latest release for your platform
# Available at https://github.com/21st-dev/1code/releases

# macOS
brew install --cask 1code

Or download the .dmg (macOS), .exe (Windows), or .AppImage (Linux) from the releases page.

Configure API Keys

On first launch, 1Code prompts for your API keys. It supports:

• Anthropic API key (for Claude Code)
• OpenAI API key (for Codex)
• Any OpenAI-compatible provider via custom endpoint

Keys are stored locally and never synced to a cloud service.

Connect a Repository

1. Click New Workspace
2. Select a local git repository
3. Choose the model (Claude Code or Codex)
4. The app creates a new worktree and opens the chat panel

How Worktree Isolation Works

# 1Code creates a branch per session automatically
git worktree add ../workspace-session-abc123

# Agent operates in that worktree
# You merge when satisfied
git checkout main
git merge workspace-session-abc123
git worktree remove workspace-session-abc123

The app handles worktree lifecycle automatically. You see all active worktrees in the sidebar and can switch between them.

FAQ

Q: Is this affiliated with Anthropic or OpenAI? A: No. 1Code is an independent open-source project by 21st.dev. It uses the official Claude Code CLI and Codex APIs under the hood.

Q: Can I self-host the cloud sandboxes? A: The cloud sandbox feature requires 21st.dev’s infrastructure in the current release. The local desktop app with git worktree isolation is fully self-hosted.

Q: How does this compare to Cursor? A: Cursor is a proprietary IDE with an integrated agent. 1Code is a wrapper around existing CLI agents (Claude Code, Codex) that adds a visual layer — you get the same underlying model behavior with more operational transparency. 1Code is Apache-2.0; Cursor is not open source.

Q: Does it support Windows and Linux? A: Yes. Cross-platform desktop app alongside macOS.

Q: What is the model selector? A: A dropdown in the UI to switch between Claude Code, Codex, and any custom OpenAI-compatible provider you configure.

Conclusion

1Code fills the gap between “I want to use Claude Code with a visual UI” and “I want to own my infrastructure.” The git worktree isolation alone makes it worth trying if you have ever accidentally committed bad agent output to your main branch. With 5,600+ stars and an active open-source community, it is a credible alternative to Cursor for teams that want transparency and self-hostability.