One record, from sign‑up to report.
Fraud moves from a SIM swap to a payout in minutes. Sieve puts six tools on one customer record, behind one API.
Decide before the money moves.
Send an event, from sign-up to payout. Get allow, review or block back at once, with the reasons.
One set of rules covers M-Pesa, Airtel Money, cards, bank transfers and crypto withdrawals.
- Typically answers in under 50 ms
- Safe to retry; test and live kept apart
- Watch first, enforce when ready
- Signed webhooks for blocks, cases and sanctions matches
- Phone number and payout account changed 16 minutes after signupdetails_changed_after_signup+35
- Payout account added 5 minutes agopayout_to_new_destination+25
- Withdrawing 99% of the balanceaccount_drain+21
Rules you can read. Numbers you can change.
Sieve ships thirty-one plain-English rules, plus your own. They combine into seven fraud patterns, each with an alert line and a block line.
- Off, Watch or Enforce: test any rule on live traffic without blocking anyone
- Replay the last 30 days before you save a change
- Hit rate and precision for each rule, from your verdicts
- Every change versioned and logged, with who made it
- Recent SIM swapEnforce
Flag money leaving within 72 hours of the SIM card being swapped.
- Money in, straight back outEnforce
Flag when 80% of money received in the last 24 hours leaves again.
- Amounts kept under the thresholdWatch
Flag 3 or more transactions within 7 days between 80% and 100% of the reporting threshold.
The case file, written before you open it.
The Sieve Agent gathers the evidence, cites each event and weighs the innocent explanation. It recommends an outcome and drafts suspicious transaction reports.
- Runs on Claude or a model you host; never sees names, phone numbers or emails
- Ignores instructions hidden in customer records
- Recommends only: it cannot close cases, change rules or move money
- Spots event sequences your rules miss; its proposals are backtested and start in Watch
New-account cash-out using a borrowed identity
Find the hole before a fraudster does.
Much fintech fraud starts in the fintech’s own code. Code Guard scans your repositories for twenty classes of flaw that fraudsters exploit.
- Callback verification for M-Pesa, Paystack, Flutterwave and Stripe
- Double-spend races, idempotency, IDOR and mass assignment
- Payout 2FA, OTP strength and throttling, leaked secrets
- Each fix comes as a prompt for your coding agent
Anyone with the callback URL can fake a “payment received” and withdraw money that never arrived.
Start with one call before each payout.
That alone protects your payouts. Add sign-ups, logins and detail changes to switch on every rule. Use our Node.js SDK, or JSON over HTTPS from any language.
- payout.requested
- customer.created
- customer.updated
- login
- transaction
// npm install @sievefraud/node import { Sieve } from '@sievefraud/node' const sieve = new Sieve('sv_live_…') // Before you release a payout, ask Sieve. const d = await sieve.events.create({ type: 'payout.requested', customer_id: user.id, amount: 48000, destination: { type: 'mpesa', account: payout.phone }, }) if (d.decision === 'block') return res.status(403).json({ error: 'Payout held for review' }) if (d.decision === 'review') await holdPayout(payout.id, d.reasons)