> ## Documentation Index
> Fetch the complete documentation index at: https://goldrush.dev/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# GoldRush x402: Pay-Per-Request Blockchain Data via Micropayments

*Published February 17, 2026*

![GoldRush x402: Pay-Per-Request Blockchain Data via Micropayments](https://www.datocms-assets.com/86369/1780000650-17_goldrush_x402_pay-per-request_blockchain_data_for_agents.jpg)

We’ve launched GoldRush x402 — a payment-gated proxy that lets you access the full GoldRush blockchain data API by paying per request with stablecoins on Base, using the x402 protocol. **No API key, no account, no credit card**. Live now on Base Sepolia testnet.

## What’s new

GoldRush x402 is a reverse proxy in front of `api.covalenthq.com` that replaces API key authentication with micropayments. When you call an endpoint without payment, the server responds with `402 Payment Required` and payment instructions. Your x402 client pays, retries, and gets the data, all in a single request-response cycle.

## Why it matters

* Zero-friction access: No signup, no billing page, no minimums. Pay only for what you use.
* Agent-native: AI agents can discover endpoints, evaluate pricing, and pay from their own wallets at runtime with no human in the loop.
* Pre-payment validation: Requests are validated before you are charged. Malformed addresses or unsupported chains return errors at zero cost.
* Smart caching: Cached responses (30s for balances, 5m for pricing) cost less.
  Coverage
* 60+ endpoints — balances, NFTs, transactions, blocks, DEX data, pricing, security, and cross-chain operations
* 100+ chains — Ethereum, Base, Arbitrum, Optimism, Polygon, Solana, Bitcoin, and more

## Pricing model

* **Fixed-price endpoints (balances, NFT holdings, block details):** one price per call.
* **Tiered endpoints (transactions, event logs):** choose a tier (Small/Medium/Large/XL) based on expected response size. Overshoot and you overpay slightly; undershoot and you get a 402 telling you the correct tier.

## Endpoint discovery (free)

```
# List all endpoints with pricing
curl https://x402.goldrush.dev/v1/x402/endpoints | jq

# Search for specific functionality
curl https://x402.goldrush.dev/v1/x402/search?q=balance | jq
```

## Quick start

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

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

const BASE = "https://x402.goldrush.dev/v1";
const balances = await client.get(
  `${BASE}/eth-mainnet/address/${walletAddress}/balances_v2/`
);
```

## What’s next

* Base mainnet launch
* Credit system for overpayments
* WebSocket streaming with per-message micropayments
* Open-sourcing the proxy

## Get started

GoldRush x402 is live on Base Sepolia testnet. Testnet stablecoins are free so you can build and test today at zero cost. Track transaction volume on [x402scan](https://www.x402scan.com/).

[Learn more](https://goldrush.dev/docs/goldrush-x402/overview)