FetchDelta is a paid HTTP API for AI agents that need fresh public web pages as clean markdown or structured diffs.

What pages should agents use FetchDelta for?

FetchDelta is best for public docs, release notes, changelogs, pricing pages, and policy pages that an agent needs to check before answering or acting.

How does payment work?

FetchDelta returns HTTP 402 payment requirements and accepts x402 payments over Base mainnet USDC for individual resolve or diff requests.

FetchDelta Quickstart

Start with one narrow workflow: let an agent re-check docs, release notes, pricing, or policy pages only when it needs fresh public web state. The paid path uses x402 on eip155:8453 with USDC settlement.

Try your URL free Pricing Markdown API x402 API Manifest JSON OpenAPI JSON llms.txt Agent card

Try your URL free Open pricing Markdown API Inspect the 402 flow Open machine-readable manifest

Best first buyer: an internal agent that answers questions from product docs or release notes and occasionally needs a fresh fetch before it replies.

What Is FetchDelta?

FetchDelta is a paid page freshness API for AI agents. It turns public web pages into clean markdown and compares watched pages against prior snapshots, so an agent can check current docs, release notes, pricing, or policy pages only when it needs fresh state.

For non-branded discovery queries, use the canonical public web page to markdown API page and x402 page freshness API page.

Use it when An agent is about to answer from stale docs, a changelog, a pricing page, or a public policy page.

Do not use it for Private dashboards, login-only pages, browser sessions, or bulk crawling jobs.

Payment model Each paid request uses HTTP 402 and x402 over Base mainnet USDC.

Pricing

Open the dedicated pricing page for the canonical price answer and buyer references.

$0.002 /api/resolve per request, about 500 calls per $1

$0.004 /api/diff per request, about 250 calls per $1

Try the preview first

Use the free preview for your real URL The preview endpoint returns title, excerpt, headings, links, and a truncated markdown sample before you pay for the full response.

Promote only useful pages to the paid path If the sample looks useful, switch to the paid resolve or diff endpoint for the same URL.

https://fetchdelta.com/preview

https://fetchdelta.com/api/resolve/preview?url=https%3A%2F%2Fexample.com%2F

Best First Workflow

1. Pick one page your agent already cares about Start with a docs page, changelog, pricing page, or policy page that already appears in prompts or support work.

2. Pay once for the current markdown Use /api/resolve when the agent needs the current clean body, headings, and excerpt.

3. Switch to /api/diff for repeated checks After the first fetch, ask only whether the page changed and inspect the structured diff preview.

Agent Buyer Flow

1. Inspect the endpoint Hit a paid URL and read the 402 Payment Required response headers.

2. Retry with an x402-capable client Use a Base wallet and pay exactly for the request you want.

3. Consume normalized JSON The unlocked response contains clean markdown or a structured diff, not raw page HTML.

Inspect the Paywall

curl -i 'https://fetchdelta.com/api/resolve?url=https%3A%2F%2Fexample.com%2F'

Use the Included CLI

API_BASE_URL=https://fetchdelta.com node scripts/agent-client.js inspect resolve https://example.com

API_BASE_URL=https://fetchdelta.com EVM_PRIVATE_KEY=0x... \
node scripts/agent-client.js pay resolve https://example.com

The repository already includes scripts/agent-client.js, so buyers can inspect or pay with one command instead of wiring a client from scratch.

Paid Endpoints

/api/resolve at $0.002 per request for the current normalized page
/api/diff at $0.004 per request for “what changed since last time?”

https://fetchdelta.com/api/resolve?url=https%3A%2F%2Fexample.com%2F

https://fetchdelta.com/api/diff?url=https%3A%2F%2Fexample.com%2F

Node Buyer Example

import { wrapFetchWithPaymentFromConfig } from "@x402/fetch";
import { ExactEvmScheme } from "@x402/evm";
import { privateKeyToAccount } from "viem/accounts";

const account = privateKeyToAccount(process.env.EVM_PRIVATE_KEY);
const paidFetch = wrapFetchWithPaymentFromConfig(fetch, {
  schemes: [{ network: "eip155:*", client: new ExactEvmScheme(account) }],
});

const response = await paidFetch("https://fetchdelta.com/api/resolve?url=https%3A%2F%2Fexample.com%2F");
const data = await response.json();
console.log(data);

References For Agent Implementers

Use these primary references when validating the payment flow or wiring your own buyer client.

x402 buyer quickstart for the HTTP 402 retry flow.
Coinbase x402 buyer guide for Base-compatible buyer integration.
Cloudflare x402 documentation for Workers and agent payment context.

Good First Buyers

Docs copilots Pull the latest public docs page into markdown before answering a user question with stale context.

Release-note monitors Use /api/diff on changelog or release-note pages so the agent only reacts when something moved.

Policy and pricing watchers Track public pages that matter to compliance, quoting, or procurement without keeping a crawler alive full-time.