1 Best APIs for 3D Secure Authentication in Nigeria

Unlimit (formerly known as CardPay, then Unlimint) is a global financial technology company with over 15 years of experience in international payment infrastructure. Headquartered across multiple regional offices and operating in 200+ locations worldwide, Unlimit provides payment processing, multi-currency business accounts, Banking-as-a-Service (BaaS), and cryptocurrency on/off-ramp services to merchants, platforms, and financial institutions globally. Africa — specifically Nigeria, Kenya, and Tanzania — is explicitly listed as a supported region in Unlimit's global coverage. The company has undergone a notable branding evolution: originally known as CardPay, it rebranded to Unlimint, and subsequently to Unlimit (the current brand). Its core payment processing technology remains under the CardPay API specification (version 2.70), which continues to be used by integrators and is documented at integration.unlimit.com. The legacy GitHub repositories can be found under the "cardpay" organization on GitHub, reflecting the original brand. **Core Products** 1. **Payment Gateway** — Unlimit's flagship product: accepting card payments, local payment methods, and alternative payment methods (APMs) from customers in 200+ locations. The gateway supports over 1,000 payment methods — an exceptionally broad catalog that includes regional methods specific to Africa, Latin America, Asia-Pacific, Europe, and India. For Nigerian merchants, this means access to local Nigerian payment methods alongside international Visa, Mastercard, and Amex cards. The gateway supports both Payment Page Mode (where customers enter card details on Unlimit's hosted checkout page) and Gateway Mode (server-to-server, where the merchant's own application handles card data collection under PCI DSS compliance). 2. **Unlimit Accounts** — Multi-currency business accounts that allow businesses to hold, send, and receive funds in 30+ currencies. These accounts come with integrated card issuance for business spending and are accessible programmatically via API. For Nigerian businesses operating internationally, this provides a way to maintain USD, EUR, and GBP balances without going through traditional Nigerian commercial bank FX channels. 3. **Banking as a Service (BaaS)** — A white-label financial infrastructure layer that enables fintechs and non-bank businesses to offer card issuing, payment processing, and banking features under their own brand. The BaaS offering connects to SEPA (Euro transfers), SWIFT (international transfers), and BACS (UK transfers) payment rails. 4. **Unlimit Crypto** — An on/off-ramp service for crypto-native platforms: DeFi protocols, GameFi platforms, NFT marketplaces, and crypto exchanges can accept fiat currency from users and pay out in cryptocurrency (or vice versa) using Unlimit's crypto conversion infrastructure. **API Architecture & Authentication** The Unlimit (CardPay) API uses terminal-based credentials for authentication. Each merchant is assigned a Terminal Code and Password, which are used to generate SHA-512 HMAC signatures for request authentication — providing tamper-evident server-to-server authentication. OAuth 2.0 is used for certain API flows. The API has two primary modes: Payment Page Mode uses redirect-based flows, while Gateway Mode enables direct card processing on the merchant's own checkout page (requiring PCI DSS certification). The API is documented at integration.unlimit.com and legacy references appear on integration.unlimint.com (which redirects). **Sandbox Environment** Unlimit provides a sandbox environment for integration testing. Developers can simulate payments, test 3D Secure flows, and validate webhook integrations without processing real transactions. Sandbox credentials are separate from production credentials. **3D Secure & Fraud Prevention** Unlimit supports 3D Secure (3DS1 and 3DS2) for card authentication. In 3DS2 flows, Unlimit can collect additional customer authentication data either from the merchant's side or through an intermediate authentication page. This reduces chargebacks and strengthens payment security — particularly important for high-risk verticals like gaming, travel, and international e-commerce. **Recurring & Subscription Billing** Unlimit's gateway supports recurring payment schedules, making it suitable for subscription businesses that need to charge customers on weekly, monthly, or annual cycles without requiring manual card entry for each period. **Africa & Nigeria-Specific Context** Nigeria is one of three African markets explicitly listed in Unlimit's geographic coverage (alongside Kenya and Tanzania). For Nigerian merchants, this means Unlimit supports local Nigerian payment methods in addition to international cards. However, Unlimit is not a Nigerian-native payment provider — it is a global gateway that supports Nigeria as part of its multi-regional infrastructure. Businesses primarily serving the Nigerian domestic market may find Nigerian-native gateways (Paystack, Flutterwave) more deeply integrated with local payment methods and better suited to local developer support. Unlimit's strongest value proposition for Nigerian-connected businesses is multi-currency acceptance and serving international customer bases that include Nigeria. **Pricing** Unlimit does not publicly list pricing. Commercial terms are negotiated on a per-merchant basis depending on transaction volume, payment methods, geographic coverage, and vertical (gaming, travel, e-commerce, etc.). Merchants must contact Unlimit's sales team for pricing. This is typical for enterprise-grade global payment gateways. **Compliance & Licensing** Unlimit operates under financial services licenses in multiple jurisdictions. The company implements KYC and AML processes for merchant onboarding. Specific license details for Nigerian operations are not publicly disclosed — Unlimit operates as an international payment processor interfacing with Nigerian payment infrastructure rather than holding a direct CBN license. **Frequently Asked Questions** Q: Is Unlimit the same as CardPay? A: Yes. Unlimit was previously known as CardPay, then rebranded to Unlimint, and now operates as Unlimit. The core API documentation remains under the CardPay/CardPay API versioning. Q: Does Unlimit support Nigerian payment methods? A: Nigeria is explicitly listed as a supported market. Unlimit supports local Nigerian payment methods alongside international cards. Q: What is the difference between Payment Page Mode and Gateway Mode? A: Payment Page Mode redirects customers to Unlimit's hosted checkout for card entry. Gateway Mode processes card data directly on the merchant's site (requires PCI DSS compliance). Q: Is self-serve onboarding available? A: No. Merchant onboarding requires contacting Unlimit sales for custom pricing and a commercial agreement. Q: Does Unlimit support crypto payments? A: Yes. Unlimit Crypto provides on/off-ramp services enabling fiat-to-crypto and crypto-to-fiat conversions for DeFi, GameFi, and NFT platforms.