4 Best APIs for Invoicing in Nigeria

ErcasPay is a CBN PSSP-licensed, PCI DSS-certified, and NDPA-compliant multicurrency payment gateway built specifically for Nigerian businesses. The platform supports 8 currencies — NGN, USD, GBP, EUR, CAD, GHS, GMD, and KES — enabling Nigerian merchants to accept both local and international payments through a single API integration. ErcasPay processes transactions from 5,000+ businesses and has offices in Lagos, Abuja, and Ibadan. What the API Does The ErcasPay REST API enables developers to: initiate and process local card payments (Verve, Visa, Mastercard), bank transfers, USSD, and QR code payments; accept international card payments in 7 foreign currencies; issue and manage virtual account numbers for NGN collections; generate payment links; and create invoices. The API uses separate sandbox and live environments with distinct base URLs. How Developers Use It Developers create an account at ercaspay.com, obtain API keys from the dashboard under developer settings, and integrate using the documentation at docs.ercaspay.com. Authentication uses Bearer tokens with secret keys prefixed ECRS-TEST-SK (sandbox) and ECRS-LIVE-SK (live). Sandbox base URL: api-staging.ercaspay.com/api/v1. Live base URL: api.ercaspay.com/api/v1. All requests require Accept: application/json and Content-Type: application/json headers. Pricing Local transactions (cards, bank transfer, QR, USSD): 1.4% per transaction, capped at ₦2,000. International card transactions: 4.8% per transaction. International payments first settle to a USD wallet; conversion to NGN is triggered from there. A 10% rolling reserve is applied on international card transactions, held for 180 days — refundable if no chargebacks occur. No monthly subscription fee. Authentication Bearer token authentication. Secret key placed in the Authorization header as "Bearer {SECRET_KEY}". Separate keys for test and live modes. Keys managed from the ErcasPay Dashboard. Compliance CBN PSSP-licensed, PCI DSS certified, and compliant with the Nigeria Data Protection Act (NDPA). Multi-location presence in Lagos, Abuja, and Ibadan. Challenges and Gotchas (1) 10% rolling reserve on international card transactions held 180 days can be a significant cash flow constraint for new merchants. (2) International payments do not settle directly in NGN — they go to a USD wallet first. (3) No recurring billing or split payment support currently. (4) Rate limits not publicly documented — confirm with ErcasPay before high-volume implementations. Company Background ErcasPay is operated by ErcasPay Nigeria Limited, headquartered in Lagos with offices in Abuja and Ibadan. The company targets Nigerian businesses of all sizes needing a reliable, multi-currency alternative payment gateway. FAQs Q: What is the fee for local card payments? A: 1.4% capped at ₦2,000 per transaction. Q: Does ErcasPay support USSD payments? A: Yes. USSD is supported at the same 1.4% (capped ₦2,000) local rate. Q: What currencies can I accept through ErcasPay? A: NGN, USD, GBP, EUR, CAD, GHS, GMD, and KES — 8 currencies total. Q: Is there a sandbox? A: Yes. Sandbox at api-staging.ercaspay.com/api/v1 using ECRS-TEST-SK keys. Q: What is the rolling reserve? A: A 10% hold on international card transaction amounts, retained for 180 days. It is refunded in full if no chargebacks are filed during that period. ErcasPay's multi-currency acceptance — NGN plus USD, GBP, EUR, CAD, and additional international currencies — enables Nigerian merchants to accept payments from both domestic customers paying in naira and international customers paying in their home currency. This dual-currency capability in a single gateway integration eliminates the need for separate domestic and international payment gateway relationships, reducing integration complexity and ongoing vendor management for Nigerian businesses serving both local and global customer segments. PCI DSS certification at ErcasPay ensures that card data handling meets international security standards, protecting Nigerian merchants from the liability and reputational risk of card data breaches. For Nigerian SMEs that lack the resources to implement independent PCI compliance infrastructure, using a certified gateway like ErcasPay allows them to accept card payments within a compliant infrastructure environment without bearing the cost and complexity of independent certification.

Square API is a comprehensive payment and commerce platform API from Square, Inc. (now Block, Inc.) that enables developers to build custom point-of-sale applications, online payment flows, inventory management systems, subscription billing, and retail commerce solutions. Square provides a deeply integrated suite of commerce APIs covering payments, orders, inventory, customer management, loyalty programs, and employee management that work together to provide a complete retail and services business management platform. IMPORTANT NOTE FOR NIGERIAN DEVELOPERS: Square does not currently operate in Nigeria and does not support Nigerian merchants registering for Square accounts, processing NGN transactions, or receiving settlements to Nigerian bank accounts. Square operates in the United States, Canada, United Kingdom, Australia, Japan, France, Spain, and Ireland only. Nigerian businesses looking for equivalent payment processing capabilities should use Nigerian-licensed alternatives such as Paystack, Flutterwave, Monnify, or Kora. Despite not supporting Nigeria directly, Square API is documented here for several relevant reasons. First, Nigerian tech professionals working for international companies, remote contractors, and developers building products for non-Nigerian markets frequently work with Square. Second, Nigerian developers building applications for clients in Square-supported markets need API documentation to understand the integration requirements. Third, the architectural patterns used by Square — particularly their Payments API, Web Payments SDK, and order management system — are studied by Nigerian developers learning payment system design. The Square Payments API processes card-not-present payments through the Web Payments SDK (a JavaScript library that renders a PCI-compliant card entry form in web browsers) and the In-App Payments SDK (for iOS and Android native apps). These SDKs handle card data capture and tokenization in the browser or app, then pass a payment token to the backend which makes a charge call to the Square Payments API without sensitive card data ever touching the developer's servers. This architecture demonstrates PCI compliance best practices relevant to payment developers globally. Square Orders API provides comprehensive order lifecycle management: creating orders with line items, modifiers, and taxes, updating order status, applying discounts, processing partial fulfillments, and attaching payments to orders. This orders-centric model — where payments fulfill orders rather than existing independently — is architecturally different from many payment APIs and represents a more complete retail commerce model that connects inventory, pricing, and payment into a unified order record. Square Inventory API tracks product stock levels across multiple locations, providing real-time inventory counts, adjustment tracking, and low-stock alerting. For developers building multi-location retail management systems in Square-supported markets, the inventory API enables the stock synchronization between physical and online sales channels that prevents overselling and allows accurate availability display. Square Subscriptions API handles recurring billing, creating subscription plans with billing cadences, trial periods, and pricing tiers, and automatically charging customers on schedule. Subscription webhooks notify the integrating application of billing events, failed payments, and subscription status changes. This recurring billing infrastructure is used by subscription box services, membership businesses, and SaaS products operating in Square markets. Square Loyalty API builds customer loyalty programs directly into the payment flow, automatically awarding points on eligible purchases, tracking redemption history, and applying loyalty discounts at checkout. For businesses in Square-supported markets wanting to reward repeat customers without separate loyalty program infrastructure, the integrated loyalty system captures purchase data automatically through the normal payment flow. Nigerian developers can access Square's sandbox environment freely for learning and testing purposes, using test credentials to exercise all API endpoints without processing real payments.