# Robinhood Chain Testnet starter: keyless reads, WebSocket logs, then mainnet

> Original page: https://docs.blockvectra.com/en/guides/robinhood-testnet-starter/

BlockVectra serves Robinhood Chain Testnet (chain ID 46630) over JSON-RPC and WebSocket, and the same API key also works on Robinhood Chain mainnet. This guide follows the [Robinhood Chain Testnet starter](https://github.com/blockvectra/robinhood-testnet-starter?ref=docs-testnet-starter) template through three steps: read the testnet without a key, open an account programmatically and stream logs, then move the same key to mainnet. For endpoint parameters, method policy, and tokenized stock data, see the [Robinhood Chain guide](https://docs.blockvectra.com/en/guides/robinhood-chain/).

## Run the template

```bash
git clone https://github.com/blockvectra/robinhood-testnet-starter
cd robinhood-testnet-starter
npm install
npm run typecheck
```

Node.js 18 or newer. The three scripts are `npm run step1`, `npm run step2`, and `npm run step3`. Optional variables (`BLOCKVECTRA_API_KEY`, `WALLET_PRIVATE_KEY`) are read from the shell; nothing loads `.env` automatically.

## Step 1: read the testnet without a key

The public endpoint `https://api.blockvectra.com/v1/robinhood_testnet/public` serves wallet JSON-RPC methods with no account and no API key. Query the EIP-155 chain ID directly:

```bash
curl -s "https://api.blockvectra.com/v1/robinhood_testnet/public" \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","id":1,"method":"eth_chainId","params":[]}'
```

The response is `{"jsonrpc":"2.0","id":1,"result":"0xb626"}`; `0xb626` is the hexadecimal chain ID, which is 46630 in decimal.

The template reads the chain entry from `GET /v1/chains` and builds a viem client from it, so the chain name and ID are not hard-coded. From `src/shared.ts`:

```ts
import { createPublicClient, defineChain, http, webSocket } from "viem";

export const API_BASE = "https://api.blockvectra.com/v1";

export interface ChainEntry {
  chain: string;
  name: string;
  chain_id: number;
  data: boolean;
  ws: boolean;
  subscriptions: string[];
  public?: { url: string };
}

export async function getChain(slug: string): Promise<ChainEntry> {
  const res = await fetch(`${API_BASE}/chains`);
  if (!res.ok) throw new Error(`GET /v1/chains failed: ${res.status}`);
  const { chains } = (await res.json()) as { chains: ChainEntry[] };
  const entry = chains.find((c) => c.chain === slug);
  if (!entry) throw new Error(`${slug} not found in /v1/chains`);
  return entry;
}

export function toViemChain(entry: ChainEntry, rpcUrl: string) {
  return defineChain({
    id: entry.chain_id,
    name: entry.name,
    nativeCurrency: { name: "Ether", symbol: "ETH", decimals: 18 },
    rpcUrls: { default: { http: [rpcUrl] } },
  });
}

export function httpClient(entry: ChainEntry, url: string, apiKey?: string) {
  return createPublicClient({
    chain: toViemChain(entry, url),
    transport: http(url, apiKey ? { fetchOptions: { headers: { "x-api-key": apiKey } } } : undefined),
  });
}

export function wsClient(entry: ChainEntry, apiKey: string) {
  const base = "wss://api.blockvectra.com/v1";
  const url = `${base}/${entry.chain}/${apiKey}`;
  return createPublicClient({ chain: toViemChain(entry, url), transport: webSocket(url) });
}
```

With that module, `src/step1-public-read.ts` reads the chain ID, the latest block, and an address balance:

```ts
import { formatEther, type Address } from "viem";
import { API_BASE, getChain, httpClient } from "./shared.js";

const SLUG = "robinhood_testnet";
// Any address works; override with the first CLI argument.
const address = (process.argv[2] ?? "0x0000000000000000000000000000000000000000") as Address;

const chain = await getChain(SLUG);
const client = httpClient(chain, `${API_BASE}/${SLUG}/public`);

const [chainId, blockNumber, balance] = await Promise.all([
  client.getChainId(),
  client.getBlockNumber(),
  client.getBalance({ address }),
]);

console.log(`chain       : ${chain.name} (${SLUG})`);
console.log(`eth_chainId : ${chainId} (0x${chainId.toString(16)})`);
console.log(`block       : ${blockNumber}`);
console.log(`balance     : ${formatEther(balance)} ETH  (${address})`);
```

## Step 2: open an account programmatically and subscribe to logs

`src/step2-key-and-logs.ts` signs in with a wallet (SIWE, EIP-191) at `https://console-api.blockvectra.com/v1`. A first sign-in creates the account; the client then creates an API key. New accounts get 30,000,000 CU on sign-up — no credit card.

```ts
import { generatePrivateKey, privateKeyToAccount } from "viem/accounts";
import type { Hex } from "viem";

const CONSOLE_API = "https://console-api.blockvectra.com/v1";
const REF = "gh-robinhood-testnet-starter";

async function post<T>(path: string, body: unknown, token?: string): Promise<T> {
  const res = await fetch(`${CONSOLE_API}${path}`, {
    method: "POST",
    headers: { "Content-Type": "application/json", ...(token ? { Authorization: `Bearer ${token}` } : {}) },
    body: JSON.stringify(body),
  });
  if (!res.ok) throw new Error(`${path} failed: ${res.status} ${await res.text()}`);
  return (await res.json()) as T;
}

async function provisionKey(): Promise<string> {
  const pk = (process.env.WALLET_PRIVATE_KEY as Hex | undefined) ?? generatePrivateKey();
  const account = privateKeyToAccount(pk);
  console.log(`wallet: ${account.address}`);

  // SIWE: ask for a challenge, sign it verbatim (EIP-191), log in. A first sign-in creates the account.
  const { message } = await post<{ message: string }>("/auth/siwe/challenge", {
    address: account.address,
    purpose: "login",
  });
  const signature = await account.signMessage({ message });
  const login = await post<{ session: { token: string }; account_created: boolean }>("/auth/siwe/login", {
    message,
    signature,
    ref: REF,
  });
  console.log(`account_created: ${login.account_created}`);

  const created = await post<{ api_key: string }>("/keys", { label: "robinhood-testnet-starter" }, login.session.token);
  return created.api_key;
}

const apiKey = process.env.BLOCKVECTRA_API_KEY?.trim() || (await provisionKey());
```

If you already have a key, `export BLOCKVECTRA_API_KEY=...` skips sign-up. Without `WALLET_PRIVATE_KEY`, the script generates a throwaway wallet in memory and discards it when the run ends; set `WALLET_PRIVATE_KEY` from your local environment if you want to sign in to the same account again.

The WebSocket URL puts the key in the path: `wss://api.blockvectra.com/v1/robinhood_testnet/{api_key}`. The template checks the live `ws` flag and the `subscriptions` list from `GET /v1/chains` before subscribing:

```ts
const chain = await getChain("robinhood_testnet");
if (!chain.ws || !chain.subscriptions.includes("logs")) {
  throw new Error(`robinhood_testnet does not offer a logs subscription in /v1/chains`);
}
console.log(`subscriptions (from /v1/chains): ${chain.subscriptions.join(", ")}`);

const client = wsClient(chain, apiKey);
const stop = client.watchEvent({
  address: "0x1234567890123456789012345678901234567890",
  onLogs: (logs) => {
    for (const l of logs) console.log(`block ${l.blockNumber} ${l.address} topic0=${l.topics[0]}`);
  },
  onError: (e) => console.error("subscription error:", e.message),
});
```

Every `logs` subscription filter must include an `address` or a `topic0`; replace the example address with the contract you want to watch. See the [WebSocket subscriptions guide](https://docs.blockvectra.com/en/guides/websocket-subscriptions/) for filter rules, close codes, and reconnection.

## Step 3: switch the same key to mainnet

Mainnet is a one-word change: use the slug `robinhood_mainnet` and the same API key. `src/step3-mainnet.ts` reads the mainnet block number and calls the Data API for Robinhood stock tokens:

```ts
const apiKey = process.env.BLOCKVECTRA_API_KEY?.trim();
if (!apiKey) throw new Error("Set BLOCKVECTRA_API_KEY (run step 2 first, or create a key in the console).");

const mainnet = await getChain("robinhood_mainnet");

// JSON-RPC with the key: the chain slug changes.
const client = httpClient(mainnet, `${API_BASE}/${mainnet.chain}`, apiKey);
console.log(`mainnet block: ${await client.getBlockNumber()}`);

// Data API: Robinhood stock-token leaderboard (see the Robinhood Chain guide).
const res = await fetch(`${API_BASE}/data/${mainnet.chain}/stocks`, { headers: { "x-api-key": apiKey } });
if (!res.ok) throw new Error(`Data API failed: ${res.status} ${await res.text()}`);
console.log(JSON.stringify(await res.json(), null, 2).slice(0, 2000));
```

The same leaderboard endpoint in curl:

```bash
curl -s -H "x-api-key: $BLOCKVECTRA_API_KEY" \
  "https://api.blockvectra.com/v1/data/robinhood_mainnet/stocks"
```

The Data API is mainnet-only: `GET /v1/chains` reports `data: false` for `robinhood_testnet` and `data: true` for `robinhood_mainnet`. For request parameters and response envelopes, see the [Tokenized stocks guide](https://docs.blockvectra.com/en/guides/stocks/).

## Discover limits and capabilities from the API

Read `GET /v1/chains` for the live `jsonrpc`, `data`, `ws`, and `subscriptions` flags, the allowed JSON-RPC methods, log block ranges, state retention, and each chain's public endpoint. Read `GET /v1/plans` for current prices and plan limits.

```bash
curl -s "https://api.blockvectra.com/v1/chains"
```

## Next steps

* [Browse the datasets directory](https://blockvectra.com/en/data/) to see every dataset BlockVectra indexes.
* [See the free plan and pricing](https://blockvectra.com/en/pricing/#free) to check what your account includes.
* [Log in to the console](https://console.blockvectra.com/en/login/?next=%2Fen%2Fkeys%2F) to create an API key.