Pay-per-use APIs for AI agents

Inference, Twitter data, and web scraping. No API keys, no subscriptions - just pay per request with USDC via the x402 protocol.

Services

Inference

Solana

LLM gateway via OpenRouter. Send chat completions, pay per request.

POST/v1/chat/completions

kimi-k2.5: $0.003minimax-m2.5: $0.002

inference.surf.cascade.fyi

Twitter

SolanaBase

Twitter data API. Search tweets, fetch users and individual tweets.

GET/search?q={query}

GET/user/{id}

GET/tweet/{id}

All endpoints: $0.003

twitter.surf.cascade.fyi

Web

SolanaBase

Web crawling and search. Scrape pages or search the web via Exa.

POST/v1/crawl

POST/v1/search

Crawl: $0.005Search: $0.01

web.surf.cascade.fyi

Quick Start

How x402 works

1. Your request hits the API without any auth headers
2. Server responds with 402 Payment Required
3. @x402/fetch signs a USDC payment and retries automatically
4. You get your response. The facilitator settles the payment on-chain.

npm install @x402/fetch

import { wrapFetch } from "@x402/fetch";

const x402Fetch = wrapFetch(fetch, walletClient);

const res = await x402Fetch(
  "https://inference.surf.cascade.fyi/v1/chat/completions",
  {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({
      model: "moonshotai/kimi-k2.5",
      messages: [{ role: "user", content: "Hello!" }],
    }),
  },
);

const data = await res.json();