Paying with MPP

Hardware Hunter sells trusted price intelligence per query using the Machine Payments Protocol (MPP) — an open standard co-authored by Stripe and Tempo for autonomous machine-to-machine commerce. HTTP 402, native challenge/credential authentication, no account registration, and no API key on the paid path. If you're an AI agent with a funded Tempo wallet, you can buy cohort medians for about a cent.

What you're buying

Cohort price statistics (p25 / median / p75) for flagship PC hardware components, computed from distinct marketplace listings in a rolling 90-day window and gated on provider-established evidence:

• currency provenance (provider-stated or storefront-locale-derived, never assumed)
• condition evidence from the listing source (used / new / refurbished / open box)
• one comparable price per distinct listing — repeated fetches never inflate the sample
• minimum sample thresholds before anything is published

Benchmarks are per exact SKU: capacity is part of the identity (a 980 Pro 2TB and 1TB are different products at different prices), so every catalog entry and paid response carries a capacity field and a capacity-qualified name. Match on those, not the model name alone.

Every paid response carries benchmark_trust metadata stating the policy version and basis. Insufficient components are served free, never charged — you only pay when trusted data is returned.

The two endpoints

GET /api/x402/pricing/catalog — free discovery

No payment, no key. Lists every trusted component with its capacity, status, available condition strata, payment rails (x402, mpp_tempo), and the live per-query price. Read this first: price before you pay.

curl -s https://hardwarehunter.io/api/x402/pricing/catalog

GET /api/x402/pricing/component/{id} — the paid query

Takes a component id from the catalog. Payment is demanded only when trusted data exists; unknown or insufficient components return free (404 / truthful insufficient body).

The payment flow

1. GET the paid endpoint. A trusted benchmark returns 402 Payment Required with a standard MPP challenge: WWW-Authenticate: Payment id="<challenge_id>", method="tempo", intent="charge", realm="hardware-hunter", ... accompanied by an RFC 9457 application/problem+json envelope detailing the challenge parameters. 2. Build and sign a payment credential against those requirements (method: tempo, currency: USDC/pathUSD, amount matching the per-query price). 3. Retry the request with the Authorization: Payment <credential> header (or Payment-Authorization: Payment <credential>). 4. The server verifies and settles the transaction on the Tempo network, logs the settlement to our audit ledger, and returns 200 OK with the data payload and a Payment-Receipt: <receipt> header containing the on-chain settlement receipt.

Client example (Python)

The official pympp SDK handles the 402 challenge negotiation, payment signing, and settlement receipt cycle automatically:

from mpp.client import Client
from mpp.methods.tempo import ChargeIntent, TempoAccount
from mpp.methods.tempo.client import tempo

# Configure the Tempo payment method with an agent private key
method = tempo(
    account=TempoAccount.from_key(PRIVATE_KEY),
    intents={"charge": ChargeIntent()},
)

# Client negotiates 402 challenge, signs credential, and settles automatically
async with Client(methods=[method]) as client:
    response = await client.get(
        "https://hardwarehunter.io/api/x402/pricing/component/"
        "242957af-a870-4f47-912b-d04c1dd6f464"
    )
    data = response.json()
    print(data["summary"]["median_price"])

Networks and pricing

The catalog is the free preflight for the configured rails and advertised USD price. The 402 challenge is authoritative for payment parameters: method, intent, recipient address, and amount.

Dual-rail interoperability

Hardware Hunter endpoints support dual-rail machine payments. The paid endpoint (/api/x402/pricing/component/{id}) responds with challenge headers for both x402 (PAYMENT-REQUIRED) and MPP (WWW-Authenticate: Payment ...). Agents can pay using either standard:

• x402: EVM EIP-3009 transfer authorization via Coinbase CDP / Base.
• MPP: Tempo charge intent via pympp.

Both rails settle into the same unified audit ledger and return the exact same trusted benchmark data.

Honest limits

• The paid surface covers the components in the catalog — currently a curated flagship set (GPUs, high-capacity storage), expanding as evidence accumulates.
• Condition-stratified medians (used vs new vs refurbished) appear per component as their evidence crosses publication thresholds; the catalog shows which strata each component currently publishes.
• We do not publish trends, forecasts, or "market verdicts" — medians over verified comparable listings only. See how scoring works for what a hunt match means.

Free-tier notes

The catalog is always free, and insufficient-data responses are never charged. Every docs page also has a .md mirror. For bulk or commercial access, talk to us.