@polkadot-api/check-runtime

Detect common pitfalls when preparing or rolling out runtime upgrades on PolkadotSDK-based chains.

• Two ways to use it
  • Library: one function, getProblems(uri, options), returns a list of problems detected.
  • CLI: check-runtime problems <uri> for fast local checks and CI.

✅ Designed to be simple, deterministic, and automation‑friendly.

---

Table of contents

• Installation

• Requirements

• CLI Usage

  • Examples
  • Exit codes
  • CI integration

• Programmatic API

  • Signature
  • Parameters
  • Return value
  • Usage examples

• Problem reference

• Notes & limitations

---

Installation

Using npm

npm i @polkadot-api/check-runtime

Or run the CLI without installing globally:

npx @polkadot-api/check-runtime@latest problems wss://your.chain.rpc

---

Requirements

• Node.js 22+
• A WebSocket RPC URI for your chain (e.g. wss://...).

---

CLI Usage

The CLI exposes a single subcommand (for now), problems, that inspects a live chain and/or a provided WASM artifact (that's applied at a certain state of the chain) and prints any detected issues.

npx @polkadot-api/check-runtime@latest problems <uri> [options]

• <uri>: WebSocket RPC endpoint of the chain, e.g. wss://rpc.ibp.network/polkadot.

Options

Option	Description
--wasm <filenameOrUrl>	A path to a local runtime WASM file or a direct URL to download it. When provided, checks are performed against this WASM at the target height (see --at).
--at <block>	The height or block hash at which to check and/or apply the WASM. If omitted, the node’s latest state is used.
--symbol <symbol>	The native token symbol. If omitted, it is read from the RPC chainspec.
--decimals <decimals>	The native token decimals. If omitted, it is read from the RPC chainspec.

Examples

Check a live chain at head:

npx @polkadot-api/check-runtime problems wss://sys.ibp.network/statemine

Check a specific block:

npx @polkadot-api/check-runtime problems wss://sys.ibp.network/statemine --at 0xe67351e56ddd9f12f4e67b98c709a58a170b0eb71d168ad0b5bb17fa45becff8

Check using a locally built WASM:

npx @polkadot-api/check-runtime problems wss://sys.ibp.network/statemine \
  --wasm ./artifacts/runtime.compact.compressed.wasm

Check against a WASM downloaded from a URL:

npx @polkadot-api/check-runtime problems wss://sys.ibp.network/statemine \
  --wasm https://github.com/polkadot-fellows/runtimes/releases/download/v1.7.1/asset-hub-kusama_runtime-v1007001.compact.compressed.wasm
  --at 0xe67351e56ddd9f12f4e67b98c709a58a170b0eb71d168ad0b5bb17fa45becff8

Exit codes

• 0: No problems found: “Everything looks great!”
• 1: One or more problems detected (messages printed to stderr). This makes the command CI‑friendly.

CI integration

GitHub Actions (minimal):

name: Runtime checks
on: [push, pull_request]
jobs:
  check-runtime:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with:
          node-version: 22
      - run: npx @polkadot-api/check-runtime problems ${{ RPC_URI }} --wasm ${{ TARGET_WASM_FILE }}

---

Programmatic API

Signature

import { HexString } from "polkadot-api"

declare const Problem: {
  readonly ANCIENT_METADATA: "ANCIENT_METADATA"
  readonly MISSING_MODERN_METADATA: "MISSING_MODERN_METADATA"
  readonly MISSING_RUNTIME_APIS: "MISSING_RUNTIME_APIS"
  readonly DEV_APIS_PRESENT: "DEV_APIS_PRESENT"
  readonly MISSING_CHECK_METADATA_HASH_EXTENSION: "MISSING_CHECK_METADATA_HASH_EXTENSION"
  readonly DIFFERENT_METADATA_HASHES: "DIFFERENT_METADATA_HASHES"
  readonly WRONG_OR_MISSING_METADATA_HASH: "WRONG_OR_MISSING_METADATA_HASH"
}

type Problem = (typeof Problem)[keyof typeof Problem]

declare function getProblems(
  uri: string,
  options?: Partial<{
    wasm: HexString
    block: HexString | number
    token: Partial<{ symbol: string; decimals: number }>
  }>,
): Promise<Array<Problem>>

Parameters

• uri (string, required): WebSocket RPC URI to the target chain.
• options (optional)
  • wasm (HexString): The runtime code to check, as a hex string. When present, checks are performed against this code (at block, if provided).
  • block (number | HexString): Height (number) or block hash (hex) at which to evaluate the runtime and metadata.
  • token (Partial<{ symbol: string; decimals: number }> ): The native token information. If omitted, values are read from the chain’s spec via RPC.

Return value

A Promise<Array<Problem>> with zero or more problem identifiers. See Problem reference for details.

Usage examples

Check a live chain at head

import { getProblems } from "@polkadot-api/check-runtime"

const problems = await getProblems("wss://your.chain.rpc")
if (problems.length) {
  console.error("Issues detected:", problems)
} else {
  console.log("Looks great!")
}

Check a specific WASM at a height

import { readFile } from "node:fs/promises"
import { toHex } from "polkadot-api/utils"
import { getProblems } from "@polkadot-api/check-runtime"

const WASM_URI =
  "https://github.com/polkadot-fellows/runtimes/releases/download/v1.7.1/asset-hub-kusama_runtime-v1007001.compact.compressed.wasm"
const wasm = toHex(await (await fetch(WASM_URI)).bytes())

const problems = await getProblems("wss://rpc.my-chain.io", {
  wasm,
  block: 123_456,
})

if (problems.length) {
  console.error("Issues detected:", problems)
} else {
  console.log("Looks great!")
}

---

Problem reference

Below are the possible Problems. For each, you’ll see what it means at a high level and why it matters.

Problem	What it means	Why it matters
ANCIENT_METADATA	The runtime does not expose modern metadata ≥ v14.	Tooling that relies on modern metadata (including many SDKs and wallets) will not function correctly. Upgrade the runtime to at least metadata v14.
MISSING_MODERN_METADATA	The runtime only exposes metadata v14, not newer formats (v15/v16).	Some clients expect v15+ for enhanced correctness and hashing; remaining on v14 can limit compatibility and safety checks. Plan to migrate to v15 or v16.
MISSING_RUNTIME_APIS	The Runtime APIs required by modern tooling are missing.	Without them, metadata‑driven tools cannot interact reliably. See guidance linked in the CLI output.
DEV_APIS_PRESENT	The runtime contains **Development only Runtime APIs.	These APIs are meant for development and should not be present in a production build.
MISSING_CHECK_METADATA_HASH_EXTENSION	The CheckMetadataHash extension is not supported by this runtime's extrinsic.	Some popular offline signers may be able to create transactions for this chain.
WRONG_OR_MISSING_METADATA_HASH	The runtime was compiled without the correct metadata hash embedded.	Transactions that correctly use CheckMetadataHash will be deemed invalid.
DIFFERENT_METADATA_HASHES	The metadata hash differs between metadata v15 and v16.	Indicates an inconsistency between versions; clients may behave unpredictably.

The CLI provides short, actionable messages for each problem and exits with code 1 if any are found.

---

Notes & limitations

• The tool does not submit extrinsics and does not mutate on‑chain state; it uses Chopsticks behind the scenes.
• --at / block accepts either a height (number) or a block hash (hex string).
• When --wasm/wasm is provided together with --at/block, the height is used as the context at which to check and/or apply that specific code.
• If symbol/decimals are not provided, they are read from the chain-spec via RPC. Keep in mind that's not "on-chain" data, ie: it's safer to provide these values.