For x402 sellers
AI agents decide in milliseconds whether to pay you. These free tools show you what they see, and let you prove you're worth paying.
1. Check your endpoint free
Every check a paying agent would run, without paying: the 402 challenge, every payment option, Solana readiness, which wallets can pay, Bazaar and OpenAPI discovery. Each problem comes with a fix.
2. Your track record and badge free
x402 Doctor scans every resource in the CDP Bazaar once a day. Agents get this record before they pay you. Look yours up, then put the badge in your README or on your site: it updates daily and links to your record.
3. Prove a payment free
A buyer says they paid? Paste the PAYMENT-RESPONSE header (or a transaction and network) and see whether it's on-chain, succeeded, and how much USDC went from whom to whom.
4. Get told the moment it breaks 1 free · up to unlimited
The Fizzl endpoint monitor calls your endpoint every hour the way a paying agent does, without paying. If it stops asking for payment correctly (a 5xx, a 200 without payment, a broken challenge), you get a notification in the Fizzl wallet app on your phone, or a message on Telegram, Discord, Slack or your own webhook, and another when it works again. One endpoint is free. Pro watches 10 for $5 per 30 days, Pro 20 watches 20 for $9, and Pro Unlimited as many as you need for $20, all in USDC.
Watch my endpoint → (sign in with your wallet, no e-mail)
What agents check before paying you
Agents using x402 Doctor's pre-payment check (GET /api/v1/preflight, also in x402-safe-fetch) get go, caution or no_go. You get caution or no_go when:
- a payment would fail: wrong amount units, an unknown token, a missing Solana token account, a bad EIP-712 domain;
- the price is higher than your OpenAPI says, or the page isn't HTTPS;
- you were payable on fewer than half of your scanned days;
- several buyers reported failed payments after paying you.
Get found in the Bazaar
- Settle through the CDP facilitator (set your CDP API keys): resources that settle there (and declare discovery metadata) can be listed in the CDP Bazaar.
- Describe your resource: a clear description, input and output schema,
serviceName,tagsand an icon in your route config, and a/.well-known/x402. - Stay payable: check yourself with step 1 after every deploy (or in CI:
npx github:Fizzl13/x402-doctor <url>exits 1 on failures). - Show it: the badge from step 2 on your README and site.
- Watch it: let the endpoint monitor (step 4) tell you on your phone, Telegram, Discord or Slack when it breaks, before your buyers notice.