# polkadot-js/api

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.

Repository: https://github.com/polkadot-js/api
Canonical: https://ross.abutalabs.com/products/polkadot-js-api
Language: TypeScript
License: Apache-2.0
License Family: permissive
Topics: jsonrpc, polkadot, substrate, polkadot-js, api, web3, blockchain
Last push: 2026-07-22T12:27:11+00:00

## Health v2 (maintenance only)
Score: 88/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 93, release rhythm 76, longevity 100
- inputs: {"age_days": 3210, "days_push": 42, "days_rel": 163, "gap_med": 7, "n_releases_24m": 46}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1110, forks 387 (observed 2026-08-28T04:03:37.444581+00:00)

## What it is
A TypeScript library providing Promise and RxJS APIs for interacting with Polkadot and Substrate-based blockchain nodes via RPC calls. It dynamically generates its interfaces from the runtime metadata exposed by the connected node.

## Use cases
- query balances and chain state from a Polkadot node
- submit transactions to a Substrate-based chain
- build a dApp frontend that talks to Polkadot
- listen to on-chain events in real time
- interact with any Substrate runtime via dynamically generated types

## When to avoid
- you need a non-JavaScript language client
- you are working with chains that are not Polkadot/Substrate-based
- you only need lightweight raw JSON-RPC calls without type generation

## Facets
- artifact type: library
- maturity: active
- function: rpc, http-client, sdk, serialization
- domain: blockchain, developer-tools, apis
- platform: browser, cross-platform
- tags: polkadot, substrate, web3, rxjs, jsonrpc, blockchain-api, cryptocurrency, nodejs, typescript

## Member repositories
- polkadot-js/api (main) score 88

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:03:37.444581+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T06:43:28.087671+00:00, confidence not recorded.
  - readme: https://github.com/polkadot-js/api (fetched 2026-08-28T04:03:37.444581+00:00, sha 043219b64fb9)
- Data as of 2026-08-30T08:39:29.467469+00:00.