Polar

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

View a short video demo

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
• Launch a terminal in each bitcoin/lightning node
• Add more nodes using drag & drop
• Open & Close Channels
• Manually mine new blocks
• Deposit regtest coins into each Lightning node

Supported Network Nodes:

• LND v0.8.0 & v0.7.1
• Bitcoin Core v0.18.1
• c-lightning (coming soon)
• eclair (coming soon)

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 and Docker Compose separately

Download

The most current Polar downloads for Mac, Windows & Linux can be found in the GitHub releases

Polar's Future

The overall goal of Polar is to minimize the time & effort needed for a developer new to Lightning to get started building their next killer app. In addition, Polar aims to be a useful tool for experienced Lightning App developers to iterate faster on their projects. Less time setting up nodes, more time building your app.

Here's a short list of ideas for features that may be beneficial to add in future releases (in no particular order):

• Network snapshots with the ability to import/export them. These could also be used as templates to quickly boot up a network with predefined nodes and channels. The templates could be hosted github to allow community contributions. This may require a scripting system built-in.
• Sample app projects/code in different languages (Python, Typescript/JS, Go, C#) showing how to connect to the Lightning/Bitcoin nodes from an external app.
• Bitcoin Block Explorer & GRPC/REST API Explorers to have access to all of the node RPC API's graphically, without needing to fallback to the Terminal.
• A branded website with download links and getting started guides to make Polar a bit easier to find via search engines

Development

Commands

Command	Description
yarn	install dependencies
yarn dev	run the app with react hot reloading and electron live restarting
yarn test	run unit tests in watch mode
yarn test:e2e	run e2e tests
yarn lint:all	run typescript and eslint syntax checking
yarn langs	extract i18n language keys from code
yarn package	package the app for your OS

Tips

• install the import-sorter Visual Studio Code extension for automatic import statement sorting

Tech Stack

• 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
• 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
• Renevate 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

Recognition

Huge thanks to maintainers of Lightning Joule, Zap Wallet, LND, Bitcoin Core, along with many others for the amazing apps & libraries that gave this project inspiration, ideas & sometimes even a little code 😊.

Contact

I plan to setup a website and email soon. The best place to reach me now is on Twitter @jamaljsr. I also lurk in the LND Slack server, so you can msg me there as well.