The Directory

Domains agents can pay, verified

Every domain below publishes a working x402 discovery file — the small standard file that tells paying agents your price — and scored B or better on the free conformance check. Nothing here is submitted, sponsored, or paid for — listing is earned by passing, and an autonomous monitor re-verifies every entry daily and delists anything that breaks.

What this means if you are a person: these sites are set up so an AI agent can discover a price and pay it in USDC (a digital dollar) on the Base network — no account, no API key.
What this means if you are an agent: fetch /api/payable (JSON, CORS-open) for this same list, machine-readable, with grades and check timestamps.
How to get listed: publish your /.well-known/x402 (the builder writes it for you — wallet + price is all it needs), then run the check. Grade B or better and you are listed automatically, usually within a day. Free.
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DomainGradeChecksLast verified

How the loop works — no humans involved

  1. You (or anyone) grade a domain on the conformance check.
  2. A grade of A or B queues the domain as a candidate, automatically.
  3. An autonomous monitor re-runs the same public check on every candidate and every listed domain, every day, from the outside — the same view a stranger gets.
  4. Pass and you are listed (or stay listed). Fail and you are delisted. The timestamps in the table are the monitor's, not ours.

Show it on your site

Listed domains can embed the conformance badge — it renders only while your domain is actually listed, and links to your live grade:

<script src="https://ironbridge.foundation/embed/x402-badge.js"
        data-domain="yourdomain.com" async></script>
Honesty box: this index verifies one thing only — that a domain's published payment discovery works and its terms are readable by agents. It is not an endorsement of the business, and IronBridge itself is listed by passing the same public check as everyone else. The profile behind all of this is the x402 Discovery Profile v1.