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The Polkadot-JS project is a collection of tools, interfaces, and libraries around Polkadot and Substrate.


While the project is named after "Polkadot", know that these tools, interfaces, and libraries are fully compatible with any Substrate based chain.

Polkadot-JS API

The API provides application developers the ability to query a node and interact with the Polkadot or Substrate chains using Javascript.

The Polkadot-JS API is a library of interfaces for communicating with Polkadot and Substrate nodes.

Getting started

Follow the Getting Started guide to learn how to install and start using the Polkadot-JS API right away.

Polkadot-JS Apps

The Polkadot-JS Apps is a flexible UI for interacting with a Polkadot or Substrate based node..

This is pre-built user-facing application, allowing access to all features available on Substrate chains.

Connecting to local node

To connect the Polkadot-JS Apps to your local node, you must go into Settings and change the "endpoint to connect to" to Local Node (


If you are connected to the Polkadot-JS Apps over a secure HTTPS connection, you will need to use a browser which also supports bridging to an insecure WebSocket endpoint. For example, Google Chrome supports this, but Mozilla Firefox does not.

Polkadot-JS extension

The Polkadot-JS Extension is a simple proof-of-concept for managing accounts in a browser extension and allowing the signing of extrinsics using these accounts. It also provides a simple interface for interacting with extension-compliant dApps.

Different ways to use the extension:

Next steps



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