GoldRush x402

Pay-per-request access to GoldRush blockchain data using the x402 protocol. No API key, no signup, no billing — just a funded wallet. Provides access to Foundational API endpoints through a transparent reverse proxy.

Quick Start

import { HTTPClient } from "@x402/core";
import { ExactEvmScheme } from "@x402/evm";

const client = new HTTPClient({
  scheme: new ExactEvmScheme({
    network: "eip155:84532", // Base Sepolia
    privateKey: process.env.WALLET_PRIVATE_KEY,
  }),
});

// Get token balances — payment handled automatically
const balances = await client.get(
  "https://x402.goldrush.dev/v1/eth-mainnet/address/demo.eth/balances_v2/"
);
console.log(balances);

Install: npm install @x402/core @x402/evm

How x402 Works

1. REQUEST  → Agent calls endpoint without payment
2. 402      → Server responds with payment instructions (amount, token, recipient)
3. PAY      → Agent signs payment with stablecoins on Base, retries with proof
4. DATA     → Server validates request *before* charging, returns data

The x402 client libraries handle steps 2-3 automatically. From your code, it's just a GET request.

Key safety feature: The proxy validates your request before charging. Malformed addresses, unsupported chains, or bad parameters get a clear error — you pay nothing.

Payment: USDC on Base Sepolia (testnet). Base mainnet support coming soon.

Cross-Reference

x402 serves the same endpoints as the Foundational API with the same parameters and response format. For detailed endpoint documentation (parameters, response schemas, use cases), see the goldrush-foundational-api skill.

Base URL mapping:

Foundational API: https://api.covalenthq.com/v1/...
x402 proxy: https://x402.goldrush.dev/v1/...

Pricing Summary

Model	Description	Example
Fixed	One price per call	Token balances, NFT holdings, block details
Tiered	Price by data volume	Transactions, event logs

Tiers (for variable-length data)

Tier	Items	Use Case
Small	1-50	Quick lookups, recent activity
Medium	51-200	Standard queries
Large	201-500	Detailed analysis
XL	501+	Full history

Select tier via query parameter: ?tier=small

Response Caching

Cached responses cost less. Cache TTLs:

Balances: 30 seconds
Pricing data: 5 minutes

AI Agent Workflow

1. Discover (free)

curl https://x402.goldrush.dev/v1/x402/endpoints | jq
curl https://x402.goldrush.dev/v1/x402/search?q=balance | jq

2. Evaluate

curl https://x402.goldrush.dev/v1/x402/endpoints/get-token-balances-for-address | jq

Returns credit rate, pricing model, supported chains — everything to decide what to call.

3. Pay & consume

const balances = await client.get(
  `https://x402.goldrush.dev/v1/eth-mainnet/address/${wallet}/balances_v2/`
);
// Same JSON format as standard GoldRush API

Reference Files

Read the relevant reference file when you need details beyond what this index provides.

File	When to read
overview.md	Need x402 protocol details, pricing model breakdown, or quickstart code
ai-agents.md	Building an autonomous agent — four-step workflow, x402 vs API key comparison, rate limits
endpoints.md	Need the discovery API details (free), or the catalog of available data endpoints

goldrush-x402