OpenFDA

Official US FDA datasets: drug labels, adverse-event reports, and food recalls, queryable with Elasticsearch-style filters. Fair-use rate limits apply. Machine-payable per request.

Robinhood Chain

Offers

Offer	Endpoint	Price
Adverse events Drug adverse-event reports. Pass ?search=patient.drug.openfda.brand_name:ibuprofen&limit=5, or aggregate with &count=patient.reaction.reactionmeddrapt.exact.	`/m/openfda/drug-events`	0.01 USDG
Drug labels Structured product labeling for marketed drugs. Pass ?search=openfda.brand_name:advil&limit=1; fields include indications, warnings, and dosage.	`/m/openfda/drug-labels`	0.01 USDG
Food recalls Food enforcement (recall) reports. Pass ?search=state:CA&limit=5, or &search=reason_for_recall:listeria&sort=recall_initiation_date:desc.	`/m/openfda/recalls`	0.01 USDG

Machine-readable: openapi.json with x-payment-info offers.

Try it live

Run the full MPP flow from your browser: catch the 402, sign the payment with your wallet, and watch it settle on-chain.

Pay with an agent

Any MPP or x402-compatible client works. With mppx, payment is automatic:

// x402 exact scheme (permit2) on Robinhood Chain
// 1. GET the endpoint, read the payment-required header (base64 JSON)
// 2. Sign PermitWitnessTransferFrom against Permit2 for the advertised offer
//    (spender = x402ExactPermit2Proxy, witness.to = merchant wallet)
// 3. Retry with the payment-signature header; settlement tx arrives
//    in the payment-response header
const res = await fetch('https://api.meshgateway.co/m/openfda/drug-events', {
  headers: { 'payment-signature': signedPaymentPayload },
})

Or inspect the challenge yourself:

curl -i https://api.meshgateway.co/m/openfda/drug-events
# HTTP/1.1 402 Payment Required
# WWW-Authenticate: Payment id="…", method="evm", intent="charge", …