Polkadot does JavaScripthttps://polkadot.js.org
Promise and RxJS APIs around Polkadot and Substrate based chains via RPC calls. It is dynamically generated based on what the Substrate runtime provides in terms of metadata. Full documentation & examples available
Utilities and base libraries for use across polkadot-js for Polkadot and Substrate. Includes base libraries, crypto helpers and cross-environment helpers. Full documentation & examples available.