Payment Factory — four protocols, one endpoint

Integrate into your service

Payment Factory works for any Solana-anchored service. To accept agent payments through your own API:

1. Define your priced endpoint (e.g., /api/v1/inference or /api/v1/data-fetch).
2. Publish a .well-known/x402 manifest at <your-domain>/.well-known/x402 advertising your payTo (treasury owner pubkey), accepted asset (USDC mint), network (e.g., solana-devnet), and price per call.
3. On HTTP 402, return a Payment-Required body per the x402 spec listing your accepted protocols.
4. Clients (agents, applications using @axiom-stack/sdk client.pay() — see /developers/sdk) discover your manifest, pay via x402 (or MPP, AP2, Bearer if you accept those), and re-issue the request with proof of payment.
5. Settlement hits your treasury account on Solana — Axiom's backend is uninvolved.

Example manifest excerpt

{
  "accepts": [{
    "scheme": "exact",
    "network": "solana-devnet",
    "asset": "<your-USDC-mint>",
    "maxAmountRequired": "50000",
    "payTo": "<YOUR_TREASURY_OWNER>",
    "resource": "https://yourapi.dev/v1/inference"
  }]
}

The Axiom SDK's client.discover(serviceUrl) will find and parse this manifest automatically; client.pay() will route end-to-end between your customer's wallet and the facilitator without touching Axiom backend.

For end-to-end integration recipes (Express / FastAPI server, streaming endpoints, agent frameworks), see the Payment Factory integrations guide →

Agents with a Solana wallet pay per call in USDC — no API key, no signup, no human-mediated Stripe top-up. Coexists with Bearer on the same endpoint; we prefer Bearer when both are present (predictable enterprise margin) and fall through to x402 for spot agent traffic.

1. Precheck (no header)

curl -X POST https://api.axiomstack.dev/v1/attestation/instant \
  -H "Content-Type: application/json" \
  -d '{"asset_class": 6, "asset_id": "BTC"}'

# → HTTP 402 Payment Required
# Response body (V1-compat) + PAYMENT-REQUIRED response header (V2):
# {
#   "x402Version": 1,
#   "accepts": [{
#     "scheme": "exact",
#     "network": "solana-devnet",
#     "asset": "<USDC mint>",
#     "maxAmountRequired": "20000",          # $0.02 in 6-decimal atomic units
#     "payTo": "6pPcyDr…",                   # treasury OWNER, not ATA
#     "resource": "https://api.axiomstack.dev/v1/attestation/instant",
#     "extra": { "feePayer": "<facilitator pubkey>", "decimals": 6, "symbol": "USDC" }
#   }],
#   "error": "X-PAYMENT header is required"
# }

2. Sign + resend with payment header

# After signing (use @x402/svm + x402-fetch on Node, or solders on Python):
curl -X POST https://api.axiomstack.dev/v1/attestation/instant \
  -H "Content-Type: application/json" \
  -H "PAYMENT-SIGNATURE: <base64(PaymentPayload)>" \
  -d '{"asset_class": 6, "asset_id": "BTC"}'

# → HTTP 200 with the attestation + PAYMENT-RESPONSE header
# Response envelope includes meta.payment.tx_hash for explorer lookup.

Multi-protocol payment charge voucher. The voucher carries a pre-authorized spend envelope; settlement on Solana is async. Suits queued + batch agent workflows where the agent needs to commit a call before settlement clears.

curl -X POST https://api.axiomstack.dev/v1/attestation/instant \
  -H "X-MPP-Voucher: <base64(MPPVoucher)>" \
  -H "Content-Type: application/json" \
  -d '{"asset_class": 2, "asset_id": "AAPL"}'

# Voucher carries the pre-authorized charge envelope; settlement is async.
# Response: meta.mpp.voucher_id + meta.mpp.charged_at.

Composition patterns

Combine modes per call. The server resolves precedence in this order:

1. Bearer present → charge Bearer quota. AP2 mandate, if also present, is captured (audit trail). x402 / MPP headers, if also present, are ignored (Bearer wins).
2. x402 PAYMENT-SIGNATURE present, no Bearer → settle via x402. AP2 mandate captured if present.
3. MPP voucher present, no Bearer / x402 → settle via MPP. AP2 mandate captured if present.
4. None present → HTTP 402 with the .well-known accepts list.

Every settled call writes a receipt row visible in your dashboard: protocol, amount, on-chain tx hash where applicable, captured mandate where applicable.

See it live

Every settled call shows up in your dashboard with the full payment provenance — Bearer receipts, x402 on-chain hashes, captured AP2 mandates, MPP voucher settlement state.