polkadot-api

Features

• Light client first: built on top of the new JSON-RPC spec to fully leverage the potential of light-clients (i.e: smoldot).
• Delightful TypeScript support with types and docs generated from on-chain metadata.
• First class support for storage reads, constants, transactions, events and runtime-calls.
• Performant and lightweight: ships with multiple subpaths, so dApps don't bundle unnecessary assets.
• Uses native BigInt, instead of large BigNumber libraries
• Leverages dynamic imports to favour faster loading times.
• Promise-based and Observable-based APIs: use the one that best suit your needs and/or coding style.
• Use signers from your browser extension, or from a private key.
• Easy integration with PJS-based extensions.

... and a lot lot more.

Overview

smoldot.ts

1import { startFromWorker } from "polkadot-api/smoldot/from-worker"
2import SmWorker from "polkadot-api/smoldot/worker?worker"
3
4// Starting smoldot on a Worker (strongly recommended)
5export const smoldot = startFromWorker(new SmWorker())
6
7// Alternatively, we could have smoldot running on the main-thread, e.g:
8// import { start } from "polkadot-api/smoldot"
9// export const smoldot = start()

main.ts

1import { createClient } from "polkadot-api"
2import { getSmProvider } from "polkadot-api/sm-provider"
3import { polkadotTypes } from "@polkadot-api/descriptors"
4import { smoldot } from "./smoldot"
5
6// dynamically importing the chainSpec improves the performance of your dApp
7const smoldotRelayChain = import("polkadot-api/chains/polkadot").then(
8  ({ chainSpec }) => smoldot.addChain({ chainSpec }),
9)
10
11// getting a `JsonRpcProvider` from a `smoldot` chain.
12const jsonRpcProvider = getSmProvider(smoldotRelayChain)
13
14// we could also create a `JsonRpcProvider` from a WS connection, eg:
15// const jsonRpcProvider = WsProvider("wss://some-rpc-endpoint.io")
16
17const polkadotClient = createClient(jsonRpcProvider)
18
19// logging blocks as they get finalized
20polkadotClient.finalizedBlock$.subscribe((block) => {
21  console.log(`#${block.number} - ${block.hash} - parentHash: ${block.parent}`)
22})
23
24// pulling the latest finalized block
25const block = await polkadotClient.getFinalizedBlock()
26
27// obtaining a delightfully typed interface from the descriptors
28// previously generated from the metadata
29const polkadotApi = polkadotClient.getTypedApi(polkadotTypes)
30
31// presenting the transferrable amount of a given account
32const {
33  data: { free, frozen },
34} = await polkadotApi.query.System.Account.getValue(
35  "15oF4uVJwmo4TdGW7VfQxNLavjCXviqxT9S1MgbjMNHr6Sp5",
36)
37console.log(`Transferrable amount: ${free - frozen}`)

Documentation

Browse our latest docs here!

Announcement: Transfer of Ownership

As of 2024-02-01, the original owner and maintainer of the Polkadot-API project, Parity Technologies, has officially transferred ownership of the project to me, Josep M Sobrepere. Read more about this transfer here.