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Version: 0.17 (unstable)

Web SDK (@miden-sdk/miden-sdk)

The Web SDK is the JavaScript toolkit for the Miden network. In browsers, it wraps the Rust client as WebAssembly and exposes a typed API through the MidenClient class for web apps, wallets, dApps, and worker contexts. The same package provides a native Node.js entry backed by N-API and SQLite.

Capabilities​

  • Read and write onchain state: accounts, notes, transactions, tags.
  • Build and execute Miden transactions, including custom MASM scripts.
  • Compile Miden Assembly into account components, transaction scripts, and note scripts directly in the browser.
  • Generate zero-knowledge proofs locally via the in-browser prover, or offload proving to a remote or delegated prover.
  • Manage keys through built-in Falcon/ECDSA keystores or external signer integrations.
  • Exchange private notes through the Miden note transport network.
  • Import / export account files, note files, and full store snapshots for backup and migration.

Architecture​

┌────────────────────────────────────────────────┐
│  @miden-sdk/miden-sdk (npm)                    │
│                                                │
│  MidenClient    (typed TS API)                 │
│    │                                           │
│    ├─ accounts / transactions / notes /        │
│    │  tags / compile / keystore namespaces     │
│    │                                           │
│    └─ wraps WasmWebClient (Rust → WASM)        │
│                                                │
│  Browser default: prove / execute on a         │
│  dedicated Web Worker                          │
└────────────────────────────────────────────────┘

The browser build comes from the web-client Rust crate in 0xMiden/web-sdk, compiled with wasm-bindgen, and bundled with the WASM module, JavaScript bindings, and a dedicated Web Worker script. Under Node.js, the package selects its native N-API binding and SQLite storage instead.

Resource management​

In browsers, each MidenClient created with the default useWorker: true setting holds a dedicated Web Worker thread. When you no longer need a client — for example in a multi-wallet app that creates one client per active network — call client.terminate() to release its underlying resources. Node.js clients and browser clients created with useWorker: false do not allocate this worker, but should still be terminated when finished.

import { MidenClient } from "@miden-sdk/miden-sdk";

const client = await MidenClient.createTestnet();

// ... use the client ...

// Release client resources when you are done
client.terminate();

In environments that support the TC39 explicit resource management proposal, you can use using to let the runtime handle cleanup automatically:

{
  using client = await MidenClient.createTestnet();
  // ... client.terminate() is called automatically when the block exits
}

After terminate(), subsequent client operations throw Error("Client terminated").

Where to go next​

  • Setup — install the SDK and create your first client.
  • Accounts — create wallets, faucets, and contract accounts; look up existing ones.
  • Transactions — mint, send, consume, swap, and run custom scripts.
  • Notes — list, import, export, and transport private notes.
  • Compile — turn Miden Assembly into account components and scripts.
  • Sync and store — pull network state and manage the local database.
  • Testing — drive a fully in-memory mock chain for fast, deterministic tests.

Migrating from WebClient​

The v0.13 flat WebClient class is deprecated. The current Web SDK uses MidenClient with resource-based namespaces (client.accounts, client.transactions, …). See the Web SDK namespace migration guide for the original namespace migration.