Paying per call (x402)

Agents pay AlphaAssay per request using the x402 protocol — no account, no API key, no card form. x402 revives the HTTP status code 402 Payment Required as a machine-to-machine payment handshake.

How the handshake works

step	what happens
1 · request	your agent calls a paid endpoint like any other HTTP API
2 · quote	the response is `402` with a machine-readable price quote — the exact amount, before anything is charged
3 · pay & retry	the agent attaches the payment authorization and retries; settlement is on-chain (USDC), typically cents
4 · verdict	the full signed response — you paid for a completed trial, not for access

What it costs

From $0.10 per variant, $0.50 per new signal family — the full table is on pricing. The free tier (specimens, calibration record, certificate checks) never requires payment.

What it looks like in code

python · any x402-capable client

# with an x402 client session, a paid call is just a request —
# the client reads the 402 quote, pays (USDC), retries. You see the verdict.
r = x402_session.post("https://api.alphaassay.com/v1/assay/demo",
                      json=my_signal)
verdict = r.json()

# the quote is visible before paying, if you want to gate on price:
q = requests.post(url, json=my_signal)      # → 402 + machine-readable quote
if quote_amount(q) <= my_budget:
    r = pay_and_retry(q)

Humans and teams

If you would rather have an API key, a dashboard and an invoice: we onboard teams personally — start here. Same engine, same prices, same signed verdicts.