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Guide

Requirements

PAPI is designed to work flawlessly with almost any Polkadot-like chain. Even though, we have some requirements that the chain and environment have to fulfill.

Environment

NodeJS

PAPI is developed using the latest NodeJS LTS (currently 20.x). The minimum required version is 20.6.0, while we recommend the latest available release.

Bun

In case you are using bun as your Javascript runtime, then Papi will work flawlessly with it! Just a small detail, if using a WebSocket provider, make sure you import it from polkadot-api/ws-provider/web!

Browser

There is no specific required version, Polkadot-API works as expected in any modern browser.

Typescript

In order for PAPI to be imported correctly, and get all the types, the minimum working version of typescript is 5.2.

Chain

Node

If using Polkadot-API client through Smoldot provider (light client) there are no specific requirements.

When using the WebSocket provider with a Paritytech Polkadot-SDK based node, there are three cases:

Polkadot-SDK >= 1.11.0

Polkadot-API will work without any issues. The WebSocket provider could be used without further issues:

import { createClient } from "polkadot-api"
import { getWsProvider } from "polkadot-api/ws-provider/web"
 
const client = createClient(getWsProvider("wss://your-rpc.your-url.xyz"))

Polkadot-SDK 1.1.0 <= x < 1.11.0

If your node uses versions between 1.1 and 1.11, you are still good to go with Polkadot-API. The node implements the JSON-RPC spec wrongly, but we provide some enhancers to workaround these flaws. You need to start the connection as follows:

import { createClient } from "polkadot-api"
import { getWsProvider } from "polkadot-api/ws-provider/web"
import { withPolkadotSdkCompat } from "polkadot-api/polkadot-sdk-compat"
 
const client = createClient(
  withPolkadotSdkCompat(getWsProvider("wss://your-rpc.your-url.xyz")),
)

Polkadot-SDK < 1.1.0

The JSON-RPC spec implemented prior 1.1 was really poor and we cannot feasibly workaround it. Polkadot-API does not support those nodes.

Runtime

The most important thing to take into account is that the runtime needs to have a Runtime Metadata version >=14. We don't support any chain below that.

Besides that, Polkadot-API requires runtimes to implement some basic runtime calls. They are generally implemented in all chains developed using FRAME:

  • In order to get the metadata, it needs Metadata_metadata_versions and Metadata_metadata_at_version. If they are not present, then Metadata_metadata needs to be there and answer a v14 Metadata.
  • To create and broadcast transactions, Polkadot-API needs AccountNonceApi_account_nonce and TaggedTransactionQueue_validate_transaction. To estimate the fees, it also requires TransactionPaymentApi_query_info.

In order to create transactions as well, the following storage entry is required for obtaining the genesis block-hash:

  • System.BlockHash

And the following constant:

  • System.Version, having spec_version and transaction_version fields.