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Version: 0.14

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

The Web SDK is the browser-focused toolkit for the Miden network. It wraps the Rust client, compiles to WebAssembly, and exposes a typed JavaScript API through the MidenClient class. Use it from web apps, wallets, dApps, service workers, Node servers — any JavaScript runtime that supports Web Workers and WebAssembly.

Capabilities​

  • Read and write on-chain 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)        │
│                                                │
│  Runs prove / execute on a dedicated           │
│  Web Worker to keep the main thread responsive │
└────────────────────────────────────────────────┘

The SDK is built from the web-client Rust crate in 0xMiden/miden-client, compiled with wasm-bindgen, and bundled with the WASM module, JavaScript bindings, and a dedicated Web Worker script.

Resource management​

Each MidenClient instance 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 the worker.

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

const client = await MidenClient.createTestnet();

// ... use the client ...

// Free the Web Worker 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(), every subsequent method call throws 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. v0.14 introduces MidenClient with resource-based namespaces (client.accounts, client.transactions, …). See the v0.13 → v0.14 Web SDK migration guide for the full delta.