Buyer Quick Start

You have a Solana wallet and got HTTP 402 from a seller.

Status. Live on Mainnet (https://ipay.sh) and Devnet (https://preview.ipay.sh). Same APIs at https://agent.pay402.me / https://preview.agent.pay402.me.

Set $BASE to the facilitator URL the seller documents. Confirm cluster: GET $BASE/api/v1/facilitator/health.

Do not substitute a different facilitator origin. payTo, mint allowlists, and oracle authorities are deployment-specific.

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Default — use the SDK

npm i -g @pr402/client
pr402-buy --resource <URL> --payer <keypair.json> --mint <MINT>

One-shot: npx @pr402/client pr402-buy ... · Rust: cargo install pr402-client

Library: X402AgentClient.fetchWithAutoPay · Starter: x402-buyer-starter (createPay402Fetch, Bash/Python demos) · MCP: npx -y @pr402/mcp-server → pr402_pay_http_resource

Flow: 402 → build → sign → retry the seller with PAYMENT-SIGNATURE. The seller calls facilitator /settle. Do not call /verify or /settle as the buyer first.

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Manual path (exact rail)

For languages without a published SDK:

1. 402 — Save one accepts[] line and resource.
2. Build — POST $BASE/api/v1/facilitator/build-exact-payment-tx with { payer, accepted, resource }. If the 402 line says v2:solana:exact, send wire exact on the request.
3. Sign — Sign transaction at payerSignatureIndex. Put signed base64 into verifyBodyTemplate.paymentPayload.payload.transaction.
4. Retry seller — Same request with PAYMENT-SIGNATURE (raw JSON or base64). Seller settles and returns 200 + optional PAYMENT-RESPONSE.

Blockhash expired? Rebuild from step 2.

Build request (step 2)

curl -sS -X POST "$BASE/api/v1/facilitator/build-exact-payment-tx" \
  -H "Content-Type: application/json" \
  -d '{
    "payer": "<YOUR_PUBKEY>",
    "accepted": <THE_ACCEPTS_LINE_YOU_CHOSE>,
    "resource": <RESOURCE_FROM_402>
  }'

Retry (step 4)

curl -sS "<SELLER_RESOURCE_URL>" \
  -H "PAYMENT-SIGNATURE: $(cat verify-body.json)"

Optional — find sellers first

curl -sS "$BASE/api/v1/facilitator/providers?limit=50" | jq '.entries[] | {displayName, serviceUrl, tags}'

sla-escrow

Use POST /build-sla-escrow-payment-tx. See Agent integration and the oracles Buyer Guide.

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Advanced — buyer-side /verify + /settle

For debugging or custom flows without a seller gate. Not the default for pr402-buy, MCP, or x402-buyer-starter.

curl -sS -X POST "$BASE/api/v1/facilitator/verify" \
  -H "Content-Type: application/json" -d @verify-body.json

curl -sS -X POST "$BASE/api/v1/facilitator/settle" \
  -H "Content-Type: application/json" -d @verify-body.json

/settle is idempotent. If the seller still requires proof, retry with PAYMENT-SIGNATURE as in the manual path.

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Checklist

• Match the seller's facilitator host (preview vs mainnet).
• After build, only replace the signed transaction in verifyBodyTemplate.
• For sla-escrow, verify the seller's oracle authority before funding.

More: Agent integration · GET /openapi.json