Fintech

Fiat-to-Crypto On-Ramp Integration for Your App

Let users buy crypto with card or bank transfer directly inside your app, without building a money transmitter from scratch.

Web3 founders, DeFi protocol teams, NFT marketplace builders, and mobile app developers wanting to reduce friction for first-time crypto buyers. $0 platform fee for widget-based integrations (providers charge 1.5–4.9% per transaction). For API integrations: Sumsub $2–5/KYC, Chainalysis KYT ~$0.10–0.50/transaction, Sardine ~$0.05/transaction. 📦 8 tools
Adding a fiat-to-crypto on-ramp means your users can buy Bitcoin, ETH, stablecoins, or your native token using their credit card, debit card, bank transfer, or local payment method — without leaving your app. The core challenge is regulatory: in most jurisdictions selling crypto for fiat requires you to be a Virtual Asset Service Provider (VASP), hold a money transmitter licence, and run a full AML/KYC programme. The practical path for 95% of apps is to use a white-label on-ramp provider (MoonPay, Transak, Onramper) who holds the licences, while you embed their widget or API. This use case covers both the embedded widget path and the API-first path for more advanced integrations.

The Stack

Onramper

— On-ramp aggregator — best rates across multiple providers via single API

Onramper is a widget/API aggregator that routes each user to the cheapest available on-ramp (MoonPay, Transak, Sardine, Wyre-successor, etc.) based on their country, payment method, and crypto. You integrate once and get access to 95%+ global coverage with automatic provider fallback.

Alternatives: banxa, nowpayments

Banxa

— Direct on-ramp with strong APAC and AU coverage optional

Banxa holds licences in AU, EU, and Canada and is preferred by exchanges serving the APAC region. Lower fees than MoonPay for AU-denominated purchases. Provides hosted checkout, SDK, and REST API.

NOWPayments

— Crypto payment acceptance and conversion optional

If you also need to accept crypto payments (not just sell crypto), NOWPayments handles 300+ coins with automatic conversion to stablecoins or fiat. Useful for NFT mints, subscription paywalls, or SaaS billing in crypto.

Stripe

— Card processing for on-ramp providers in the US optional

Some on-ramp APIs (e.g. Sardine) use Stripe as the underlying card processor. If building a custom on-ramp (rare), Stripe's Crypto Onramp SDK handles card acceptance and fraud scoring for crypto purchases with specialised crypto chargeback rules.

Sumsub

— KYC/AML verification required by most on-ramp providers optional

Even when using a white-label on-ramp widget, you may need to pass KYC verification results for users you have already onboarded. Sumsub lets you share a reusable KYC status with on-ramp partners so users aren't re-verified.

Alternatives: jumio, onfido, veriff

Persona

— KYC for self-hosted on-ramp flows optional

If you are building a custom on-ramp (requires VASP licence), Persona handles ID verification + liveness check and integrates with your wallet infrastructure. Cheaper per-verification than enterprise KYC vendors at early stage.

Chainalysis

— Blockchain transaction monitoring and VASP compliance

Once a user receives crypto via your on-ramp, you must monitor on-chain activity for sanctions exposure (OFAC-designated wallet addresses). Chainalysis KYT (Know Your Transaction) screens wallet addresses at point of purchase.

Alternatives: elliptic

Sardine

— Fraud prevention specialised for crypto purchases

Crypto on-ramp fraud (stolen cards, synthetic identities, chargeback fraud) is 10–20x higher than normal e-commerce. Sardine's device intelligence and ML models are trained specifically on crypto purchase fraud patterns.

Alternatives: sift, unit21

Gotchas

  • ⚠️ Regulatory status of stablecoins: in most jurisdictions, facilitating stablecoin (USDC, USDT) purchases still qualifies as VASP activity. Don't assume stablecoins are exempt from crypto regulations.
  • ⚠️ Card network restrictions: Visa and Mastercard impose higher interchange (1.5–2.5% surcharge) on crypto purchases and allow issuers to block them. Card approval rates for crypto on-ramps are typically 60–80% vs 95%+ for normal e-commerce.
  • ⚠️ Chargeback fraud is the biggest financial risk: crypto transactions are irreversible. A chargeback fraud attack can be catastrophic. Sardine or similar fraud tooling is not optional.
  • ⚠️ FATF Travel Rule for on-chain transfers: transfers of >$1,000 (US) / €1,000 (EU) between VASPs must include sender/receiver information. Your on-ramp provider should handle this but confirm before launch.
  • ⚠️ Widget vs API tradeoffs: embedded widgets (Onramper, Transak) launch in days but you lose UX control. API integrations give full UX control but require you to manage your own VASP licence or a formal referral agreement with a licensed partner.
  • ⚠️ Geography: US is the hardest market — New York requires BitLicense (separate from MTL), and many providers restrict NY users. Always check your provider's supported states list.

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