Polar

One-click Bitcoin Lightning networks for local app development & testing

Purpose

Polar was built to help Lightning Network application developers quickly spin up one or more networks locally on their computers.

With Polar you can:

• Create a regtest Lightning Network in just a few clicks
• Connect from your app to the lightning nodes via RPC
• Add more nodes using drag & drop
• Start and stop individual nodes
• Open & Close Channels
• Create & Pay Lightning Invoices
• Launch a terminal in each bitcoin/lightning node
• View streaming logs from each node
• Manually mine new blocks
• Deposit regtest coins into each Lightning node
• Mint, Send & Receive Taproot Assets
• Create & Pay Taproot Asset invoices
• Export and import networks, for sharing with other Lightning developers
• Create you own docker images to use as custom nodes (ex: master branch, local fork)

Supported Network Node Versions:

• LND - v0.20.0, v0.19.3, v0.19.2, v0.19.1, v0.18.5, v0.18.4, v0.18.3, v0.17.5, v0.16.4
• Core Lightning - v25.12, v25.09.3, v25.05, v25.02, v24.11.1, v24.08.1
• Eclair - v0.13.1, v0.12.0, v0.11.0, v0.10.0, v0.9.0
• Bitcoin Core - v30.0, v29.0, v28.0, v27.0, v26.0
• Taproot Assets - v0.7.0, v0.6.1, v0.6.0, v0.5.1, v0.5.0, v0.4.1, v0.3.3
• Terminal - v0.16.0, v0.15.3, v0.15.1, v0.15.0, v0.14.1,

MCP (Model Context Protocol)

Polar includes an MCP server that enables AI agents like Claude & Cursor to programmatically control Lightning Network simulations.

See the polar-mcp repo for installation instructions.

See the MCP Architecture Documentation for technical information on the architecture, API, and how to add new tools to Polar.

Dependencies

Polar requires that you have Docker installed to create the local networks

• On Mac & Windows, you can just install Docker Desktop
• On Linux, you need to install Docker Server.

You will be prompted to install Docker if Polar cannot detect it automatically

⚠️ Important Docker Notes

• On Linux, Docker Desktop is currently not supported due to a significant change in how it handles file sharing between host and container (See #636)

Download

Download Polar v4.0.0 for your OS

• Mac (dmg)
• Linux (deb, AppImage, RPM)
• Windows (exe)

Alternative and older version binaries can be found in the GitHub releases

Help Translate

Polar's translations are managed on Crowdin. The initial translations of 10 languages were done by machine (Google Translate) and are likely to not be 100% accurate. If you speak multiple languages and wish to help with translations, please feel free to head over to the project page on Crowdin and submit updated strings. This assistance would be greatly appreciated.

Development

If you would like to learn how to package Polar from source code or want to fix a bug or add a new feature, please see CONTRIBUTING for detailed instructions.

Commands

Tech Stack

• Node.js: nodejs version >= 20
• Electron: cross platform desktop app framework
• Typescript: increased productivity with a typed language
• ReactJS: declarative UI library for JavaScript
• Create React App: minimize build configuration
• easy-peasy: Redux state management without the boilerplate
• Emotion: simplified CSS style composition
• Ant Design: don't reinvent the wheel with UI design
• react-i18next: support for multiple languages (english/spanish included)
• electron-log: multi-level logging to console and file
• Prettier: keep code format consistent
• ESLint: follow code quality best practices
• Github Actions: automate builds and testing on Windows/Mac/Linux
• Renovate Bot: automate dependency upgrades via GitHub bot
• Jest: delightful JavaScript testing
• React Testing Library: React specific testing utilities
• CodeCov: maintain quality of unit tests
• Testcafe: End-to-end is important
• commitlint: standardize git commit messages
• standard-version: automate release versioning and changelog generation