@anon-rpc/browser-harness

A browser harness for anon-rpc — a standard that lets a wallet or application make anonymized RPC requests by running untrusted, hash-pinned anon-client code inside a sandboxed worker.

The harness:

• resolves the anon-client bundle from an on-chain specifier contract and verifies keccak256(bytes) == workerHash() before executing a single byte (trust the hash, not the URL);
• runs it in a Web Worker inside a null-origin sandboxed iframe, with no ambient access to your DOM, storage, cookies, or keys;
• grants it a small, explicit capability API — inbound fetch calls, a KPS key-pinned transport (bridged so the worker never touches WebRTC), persistent storage (IndexedDB on the host origin, namespaced per specifier), and logging;
• hands you back one thing: an anonymized fetch.

Install

npm install @anon-rpc/browser-harness

Use

import { AnonRpcWorker } from "@anon-rpc/browser-harness";

const worker = new AnonRpcWorker({
  // The IWorkerSpecifier contract identifying the anon-client by hash.
  address: "0x…",
  // Bootstrap provider used only to read the specifier (breaks the circular
  // "need the chain to reach the chain" dependency).
  preExisting: { rpcProvider },
});

await worker.ready;

// A standard fetch, routed through the sandboxed anon-client.
// It is this-bound, so passing it around as a free function is fine.
const res = await worker.fetch("https://rpc.example/", {
  method: "POST",
  body: JSON.stringify({ jsonrpc: "2.0", id: 1, method: "eth_blockNumber" }),
});

worker.close(); // tears down the iframe and worker

Notes

• Browser-only: the isolation model is a null-origin iframe and the KPS transport runs over WebRTC. A native/Node harness would be a separate package.
• The worker-facing capability API (anonRpcWorker) and all conformance requirements are defined in the specification. A template anon-client to copy lives in impl/passthrough-worker.
• Status: prototype-grade reference implementation of a draft spec; interfaces track the spec and may change.

License

MIT © Ethereum Foundation