/runtime/spec - Polkadot

Example code for the /runtime/spec REST method. Complete guide on how to use /runtime/spec REST in GetBlock Web3 documentation.

This endpoint returns the runtime specification: the spec name and version, transaction version, and chain properties such as token symbol and decimals.

On GetBlock's unified endpoint, Asset Hub is the default network. To call this endpoint against the Relaychain, add an /rc prefix to the path (for example, /rc/runtime/spec).

Endpoint

GET /runtime/spec

Query Parameters

Parameter	Type	Required	Description
at	string	No	Block height or hash to query at

Request

cURL

curl --location 'https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/runtime/spec'

JavaScript

example.js

const response = await fetch('https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/runtime/spec');
const data = await response.json();
console.log(data);

Python

example.py

import requests

response = requests.get('https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/runtime/spec')
print(response.json())

Response

{
  "at": {
    "hash": "0x255bc00927df8d33d561792635cbc6bde480a0a505eef5ff28630ece3fc15b32",
    "height": "6754362"
  },
  "authoringVersion": "0",
  "transactionVersion": "26",
  "implVersion": "0",
  "specName": "polkadot",
  "specVersion": "1002000",
  "chainType": {
    "live": null
  },
  "properties": {
    "ss58Format": "0",
    "tokenDecimals": [
      "10"
    ],
    "tokenSymbol": [
      "DOT"
    ]
  }
}

Response Fields

Field	Type	Description
specName	string	Runtime spec name (polkadot)
specVersion	string	Runtime spec version
transactionVersion	string	Transaction format version
properties	object	Chain properties (SS58 format, decimals, symbol)

Use Cases

• Upgrade Detection: Detect runtime upgrades by specVersion

• Transaction Signing: Read the transaction version

• Chain Config: Read token decimals and SS58 format

• Tooling: Configure SDKs against the runtime