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Joule

Joule is a Chrome browser extension that uses WebLN to connect web pages to a user's Lightning node, enabling Lightning payment requests and use of the node as a web identity.

Explore the practical guide ↓

Independent OpenViST project profile, based on linked sources.

Joule — OpenViST project profile in Payments & Stablecoins.
OpenViST project illustration. See the linked sources for product details.
Understand the project

Practical overview

When it fits

Use Joule as a reference for WebLN extension development or to understand its documented payment and identity flow. The repository says the extension is no longer actively developed and warns against using it for large mainnet funds.

Who it is for

  • People exploring WebLN payments and node-based identity on the web.
  • Developers studying how to build a WebLN browser extension.

Documented uses

  • Connect a web page to a Lightning node through WebLN.
  • Respond to Lightning payment requests from compatible web pages.
  • Use a Lightning node as an identity on the web.
  • Study a TypeScript browser-extension implementation with background, content and in-page scripts.
Before you choose

Requirements & limits

  • Joule is a Chrome browser extension, and its documented development setup loads an unpacked build through Chrome's extensions page.
  • The codebase uses TypeScript, React and Redux, with distinct background, content and in-page scripts.
  • The maintainers say development has stopped and advise against using it for large mainnet funds.

Check current requirements in the official documentation. Source-based guidance does not mean OpenViST has run or independently tested this project.

Source-based practical guide

Load a development build in Chrome

Install dependencies, build Joule for development and load the unpacked extension in Chrome.

Before you start

  • The Joule repository
  • Yarn
  • Chrome

Steps

  1. Run yarn install && yarn run dev in the project.

  2. In Chrome, open More Tools → Extensions and enable Developer mode if the toggle is available.

  3. Choose “Load unpacked” and select the generated joule-extension/dist-dev folder.

Expected outcome

Chrome loads the development build from the dist-dev folder.

Guide limitations

  • The repository says Joule is no longer actively developed.
  • The README says to close and reopen the extension after making changes to load the latest build.
  • The repository cautions against using Joule for large mainnet funds.
Documentation 1 ↗
Evidence and transparency

Sources & review

Official repository ↗
Source record details
Source availability
Active
Sources checked
16 October 2026
Original website title
joule-labs/joule-extension · Official homepage title · retained in its source language
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