NASA Open APIs

NASA's public api.nasa.gov endpoints served with the DEMO_KEY tier: Astronomy Picture of the Day, near-Earth object feeds, and DONKI solar flare events. Machine-payable per request.

Robinhood Chain

Offers

Offer	Endpoint	Price
Astronomy Picture of the Day Today's APOD with title, explanation, and image URL. DEMO_KEY is pre-applied; optionally pass &date=2026-01-01.	`/m/nasa-open-apis/apod`	0.003 USDG
Solar flare events DONKI space weather solar flare events. DEMO_KEY pre-applied; optionally pass &startDate=2026-08-01&endDate=2026-09-16.	`/m/nasa-open-apis/donki-flares`	0.005 USDG
Near-Earth objects Asteroids approaching Earth this week from NeoWs. DEMO_KEY pre-applied; optionally pass &start_date=2026-09-10&end_date=2026-09-17.	`/m/nasa-open-apis/neo-feed`	0.005 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/nasa-open-apis/apod', {
  headers: { 'payment-signature': signedPaymentPayload },
})

Or inspect the challenge yourself:

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