Where to list your x402 API: Bazaar, x402scan, 402 Index, Agent402, x402dash and x402-trust

Agents can only pay for an API they can find. If you sell an API over x402, list it in the places agents and their tools search: the Coinbase x402 Bazaar first, then x402scan, 402 Index, Agent402, x402dash and x402-trust.com. All of them are free. Most take a single API call or form, and the two facilitator catalogs fill themselves from real payments.

We list our own x402 APIs in every one of these, so this guide combines each directory’s public docs (linked, read on 2026-10-22) with what happened when we submitted. The old x402.org ecosystem page is gone (it returned 404 when we checked in October 2026), so it isn’t on the list.

The directories at a glance

Before you submit anywhere: a 5-point checklist

1. An unpaid request returns a real 402. It should carry the payment terms (price, network, token, payTo) in the PAYMENT-REQUIRED header for x402 v2. Directories probe your URL, and the live 402 is what they trust.
2. GET and HEAD answer 402 too, not just POST. Probes are read-only. PayAI’s catalog worker sends HEAD, then GET, and never POST. We had one POST-only route rejected by x402dash because its GET probe got a 405. Answering GET and HEAD with the 402 fixed it.
3. Publish /openapi.json. x402scan treats OpenAPI as the canonical discovery format, with x-payment-info on paid operations and a contact email in info.contact.
4. Write a description an agent can use. Say what the endpoint does and when to call it. Coinbase rejects verify and settle requests whose description is over 500 characters, and the Bazaar screens metadata for text that reads like instructions to an agent.
5. Use your own domain. The Bazaar weights shared tunnel domains (like ngrok) lower, and PayAI refuses tunnel and preview hosts outright.

1. Coinbase CDP x402 Bazaar and Agentic.Market

This is the big one. Coinbase says the Bazaar lists more than 23,000 x402 resources and is searchable through CDP APIs, the Bazaar MCP server and agentic.market. There is no registration form. Per the Get discovered docs:

• Declare Bazaar metadata in your 402. The CDP SDK’s createX402Server does it automatically for routes written as "GET /path"; in Python, discovery is opt-in.
• Validate for free: POST https://api.cdp.coinbase.com/platform/v2/x402/validate with your resource URL and method. No API key is needed.
• Complete one successful paid call that settles through the CDP Facilitator. Indexing runs after that payment and can take up to 15 minutes.
• A resource that goes 30 days without a settlement is removed from the catalog.

To check that you are listed, query the public merchant lookup with your payTo address (/platform/v2/x402/discovery/merchant?payTo=0x..., no key needed). When we did this for our own StackDetect API on 2026-10-22, the endpoint appeared within a minute of its first settled payment, and agentic.market showed it under our domain.

2. PayAI Bazaar

PayAI runs its own facilitator catalog. Per its docs, listing is automatic: when the PayAI facilitator verifies or settles a payment that carries your discovery declaration, it catalogs the resource. Since 2026-07-29 this happens on /verify too, so no funds need to move. Before the first listing, it either needs a settled payment or a read-only probe that answers 402. A /discovery/listing-status endpoint tells you why a resource isn’t listed.

3. x402scan

x402scan tracks x402 payment volume and catalogs resources. Register your origin at x402scan.com/resources/register. It reads your /openapi.json and registers every paid operation it can verify. Re-registering the same origin after you add routes picks up the new ones. That’s how we add each new tool.

4. 402 Index

A protocol-agnostic directory (L402, x402 and MPP). Register an endpoint with POST https://402index.io/api/v1/register; url, name and protocol are required. The endpoint is probed and then goes into review, and registrations are rate-limited to 10 per hour per IP. If you verify your domain through its claim flow, you can edit your listings. In our experience, our endpoints were approved once the domain was verified. API docs.

5. Agent402

Agent402 sells its own tools to agents and also routes buyers to outside x402 sellers. Its homepage invites sellers to “serve x402 challenges and register your origin” with POST https://agent402.tools/api/index/register and a JSON body of {"origin": "https://your-api.com"}. The response says whether you are listed and routable.

6. x402dash

x402dash monitors x402 endpoints for liveness and indexes them. Per its llms.txt, register with POST https://api.x402dash.com/v1/register and {"url": "..."} (only url is required, 5 per hour), or use the form at x402dash.com/submit. It checks availability every 30 minutes and gives each endpoint a liveness score.

7. x402-trust.com

x402-trust.com scores endpoints for agents that want a check before they pay. It finds endpoints on its own from the Bazaar, facilitator lists and x402scan, and its free submit form (no signup) queues anything it hasn’t found. New entries appear after the next discovery sweep, which runs at most 6 hours apart. Optional provider verification adds a badge but, per its docs, never changes the score. Careful: its documented removal action permanently blocklists your host from automatic discovery.

Have an MCP server too?

Also publish it to the Official MCP Registry (registry.modelcontextprotocol.io), the public registry of MCP servers. We publish ours with the mcp-publisher CLI, using DNS verification of our own domain as the namespace. Then see who else sells paid tools: paid MCP servers that accept USDC.

And list it here

YourAITools is a directory of AI tools and APIs that accept crypto. Listing is free: submit your tool. We verify the live payment terms before publishing. Still building the paywall? See how to accept USDC for your API, or have us x402-enable your API, with directory listings included.