Crypto & cross-border

For remittance companies, stablecoin payment firms, exchanges and on/off-ramps: every amount compared in one currency, every corridor known, every wallet screened.

One currency for the rules

Send each amount in the currency it moved in. Sieve converts it to your workspace currency before any rule runs, so a USD 1,000 transfer and a KES or NGN 1,000 top-up are never confused, and thresholds such as CBK’s KES 1M line in Kenya or the NFIU’s NGN 5M line in Nigeria apply across currencies. The original amount, the rate and its source are stored with the event and returned in the response.

// A USD remittance from Nairobi to Kampala, on a KES workspace.
const d = await sieve.events.create({
  type: 'transaction',
  customer_id: 'cus_2044',
  direction: 'out',
  amount: 800,
  currency: 'USD',            // converted to KES for the rules; the original is kept
  method: 'bank',
  counterparty: { name: 'Grace Nakato', account: 'UG-STANBIC-00419', country: 'UG' },
})
// d.amount → { value: 103728.68, currency: 'KES', original: { value: 800, currency: 'USD' }, fx_rate: 129.66, fx_source: 'open.er-api.com' }

Rates come from your own entries in Settings → Currencies first, then a daily feed, then a bundled table so a new workspace works immediately. If a currency has no rate, the event is still scored and the response carries a warnings entry saying so.

Crypto transfers

// A customer withdraws 350.25 USDT on Tron to an exchange-hosted wallet.
const d = await sieve.events.create({
  type: 'payout.requested',
  customer_id: 'cus_1001',
  // The fiat value: every rule scores this (converted to your workspace currency if needed).
  amount: 350.25,
  currency: 'USD',
  method: 'crypto',
  // The on-chain amount, at full precision.
  asset: { code: 'USDT', amount: 350.25, network: 'tron' },
  destination: { type: 'crypto_wallet', account: 'TR7NHqjeKQxGTCi8q8ZY4pL8otSzgjLj6t', network: 'tron', country: 'AE' },
  balance: 360,
  // FATF Travel Rule data (stored encrypted). Required above the threshold.
  travel_rule: {
    originator: { name: 'Wanjiru Kamau', account: 'cus_1001', country: 'KE' },
    beneficiary: { name: 'Wanjiru Kamau', address: 'TR7NHqjeKQxGTCi8q8ZY4pL8otSzgjLj6t' },
    beneficiary_vasp: 'Example Exchange FZE',
  },
})
// d.wallet → { chain: 'tron', valid: true, network_matches: true, sanctioned: false, … }

// Deposits are transactions with the same shape; the source wallet goes in counterparty.wallet.
await sieve.events.create({
  type: 'transaction',
  customer_id: 'cus_1001',
  direction: 'in',
  amount: 128000,
  currency: 'KES',
  method: 'crypto',
  asset: { code: 'BTC', amount: 0.0153421, network: 'bitcoin' },
  counterparty: { wallet: 'bc1qar0srrr7xfkvy5l643lydnw9re59gtzzwf5mdq' },
})

• Address checks. Bitcoin, Ethereum and EVM chains, Tron, Solana, XRP, Litecoin, Dogecoin, Bitcoin Cash and more are recognised, with checksums verified where the format has one.
• Sanctioned wallets. OFAC and OpenSanctions name crypto addresses alongside people. Sieve indexes every listed address when the lists sync (over a thousand on the OFAC list alone) and blocks any transfer to or from one. This rule can’t be switched off.
• On-chain risk (optional). Connect Chainalysis’ free sanctions API, or TRM, Elliptic or your own analytics through a small adapter, and wallets exposed to mixers, scams, hacks or darknet markets are flagged. Verdicts are cached for a day, and a slow provider never delays a decision.

The Travel Rule

FATF Recommendation 16 expects originator and beneficiary information to travel with crypto transfers above a threshold (USD 1,000 equivalent by default; editable on the rule). In Kenya the VASP Act applies to crypto businesses; in Nigeria, virtual asset service providers are regulated by SEC Nigeria. Check the exact obligations and threshold with your regulator. Send it in travel_rule; it is stored encrypted. Transfers above the threshold without it, or with gaps, are flagged with exactly what is missing. Set self_hosted: true when the other side is an unhosted wallet, so no counterparty VASP is expected.

Rules

Two preset patterns combine them: Crypto cash-out (new money leaving as crypto to a fresh wallet on a new account) and Cross-border layering (funds gathered from many senders and pushed out across borders). The FATF lists are dated in Settings; review them after each FATF plenary.