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ActiveMerchant (Ruby Payments Library)
Reference entry · last updated 20260910
ActiveMerchant is an open-source Ruby payment library extracted from Shopify. It provides a common interface to supported payment gateways and can be used in Rails or standalone Ruby applications.[1]
1. First principles: a gateway adapter
The library translates application calls into gateway-specific requests. A shared method name does not make all gateways support the same capabilities. The project maintains gateway-specific implementations and a supported-features table.[1]
2. Payment operations
The base gateway documents operations including authorize, capture, purchase, void, and refund. Their arguments include amounts, payment credentials or authorization identifiers, and gateway options.[2]
A gateway’s support for partial or multiple captures must be checked separately.
3. Amounts and responses
The README’s dollar example passes integer cents: 1000 represents USD 10.00. Its purchase example checks response.success? and reads response.message.[1]
4. Scope
ActiveMerchant is an integration library. Merchant acquiring arrangements, card-data security responsibilities, and dispute processes remain part of the payment system.
5. See also
- Online Payments
- Payment Service Providers (Merchant Payments)
- Card Authorization and Capture
- PCI DSS (Payment Card Data Security)