# @polkadot-api/merkleize-metadata

Latest version **1.3.1** (published 2026-09-01) · MIT license · 0 weekly downloads

## Install

```sh
npm install @polkadot-api/merkleize-metadata
pnpm add @polkadot-api/merkleize-metadata
yarn add @polkadot-api/merkleize-metadata
bun add @polkadot-api/merkleize-metadata
```

## Health

**Score 75/100 (B)** — status: active.

Positive: has types; esm support; no vulnerabilities; has provenance; recently updated; high maintenance score; high quality score.

Warnings: low downloads.

## Facts

| | |
|---|---|
| Version | 1.3.1 |
| Published | 2026-09-01 |
| First published | 2024-07-02 |
| Weekly downloads | 0 |
| License | MIT |
| TypeScript types | bundled |
| Module format | ESM + CommonJS |
| Dependencies | 3 |
| Unpacked size | 473 KB |
| Known vulnerabilities | 0 |
| Install scripts | no |
| Provenance | attested (GitHub Actions) |
| GitHub stars | 155 |
| Author | Carlo Sala (https://github.com/carlosala) |
| Maintainers | voliva, josepot |

## Links

- npm: https://www.npmjs.com/package/@polkadot-api/merkleize-metadata
- Repository: https://github.com/polkadot-api/polkadot-api
- npm.io page: https://npm.io/package/@polkadot-api/merkleize-metadata

## Dependencies (3)

- [@polkadot-api/utils](https://npm.io/package/@polkadot-api/utils.md) 0.4.0
- [@polkadot-api/metadata-builders](https://npm.io/package/@polkadot-api/metadata-builders.md) 0.15.1
- [@polkadot-api/substrate-bindings](https://npm.io/package/@polkadot-api/substrate-bindings.md) 0.21.1

## Recent versions

- 1.3.1 (latest) — 2026-09-01
- 1.3.2-canary.49bdaa9 (canary) — 2026-09-01
- 1.2.4-rc.1 (rc) — 2026-07-08
- 1.3.2-canary.786fa29 — 2026-09-01
- 1.3.1-canary.2bce46a — 2026-08-20
- 1.3.1-canary.e24aebd — 2026-08-20
- 1.3.0 — 2026-08-18
- 1.3.1-canary.d8b2d3d — 2026-08-18
- 1.2.5-canary.8c00f44 — 2026-08-17
- 1.2.5-canary.57eb571 — 2026-07-29
- 1.2.5-canary.996069a — 2026-07-29
- 1.2.5-canary.7f105ae — 2026-07-28
- 1.2.5-canary.9390531 — 2026-07-20
- 1.2.5-canary.22b1f2b — 2026-07-20
- 1.2.5-canary.fdb7fff — 2026-07-13
- … 137 more at https://npm.io/package/@polkadot-api/merkleize-metadata/versions

## README

# @polkadot-api/merkleize-metadata

This TS package provides utils for the merkleization of [`frame_metadata`](https://docs.rs/frame-metadata/latest/frame_metadata/) as described in
[RFC78](https://polkadot-fellows.github.io/RFCs/approved/0078-merkleized-metadata.html).

## Usage

```ts
import { merkleizeMetadata } from "@polkadot-api/merkleized-metadata"

const ksmMetadata = new Uint8Array(await readFile("ksm.bin"))
const merkleizedMetadata = merkleizeMetadata(ksmMetadata, {
  decimals: 12,
  tokenSymbol: "KSM",
})

// it returns the digest value of the metadata (aka its merkleized root-hash)
const rootHash = merkleizedMetadata.digest()

// given an extrinsic, it returns an encoded `Proof`
const proof1: Uint8Array = merkleizedMetadata.getProofForExtrinsic(
  // Hex for the transaction bytes
  "c10184008eaf04151687736326c9fea17e25fc5287613693c912909cb226aa4794f26a4801127d333c8f60c0d81dd0a6e2e20ea477a06f96aaca1811872c54c244f0935c60b1f8a38aabef3d3a4ef4050d8d078e35b57b3cf4f9545f8145ce98afb8755384550000000000001448656c6c6f",
  // Optionally, we can pass the tx additional signed data
  "386d0f001a000000143c3561eefac7bc66facd4f0a7ec31d33b64f1827932fb3fda0ce361def535f143c3561eefac7bc66facd4f0a7ec31d33b64f1827932fb3fda0ce361def535f00",
)

// given the extrinsic "parts", it returns an encoded `Proof`
const proof2: Uint8Array = merkleizedMetadata.getProofForExtrinsicParts(
  // Call data
  "0x040300648ad065ea416ca1725c29979cd41e288180f3e8aefde705cd3e0bab6cd212010bcb04fb711f01",
  // Signed Extension data included in the extrinsic
  "0x2503000000",
  // Signed Extension data included in the signature
  "0x164a0f001a000000b0a8d493285c2df73290dfb7e61f870f17b41801197a149ca93654499ea3dafe878a023bcb37967b6ba0685d002bb74e6cf3b4fc4ae37eb85f756bd9b026bede00",
)

// The type `Proof` definition is as follows:
// interface Proof {
//   leaves: Array<LookupEntry>,
//   leafIdxs: Array<number>,
//   proofs: Array<Uint8Array>,
//   extrinsic: ExtrinsicMetadata,
//   info: ExtraInfo
// }
```

---
_Source: https://npm.io/package/@polkadot-api/merkleize-metadata · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._