I’m ready to standardise and streamline payments across several e-commerce shops and marketplace portals we manage. To do that, I need a single orchestrator layer that can sit between each site and the individual gateways—PayPal, Stripe, and Square—so our developers can call one clean API instead of three different SDKs. Scope • Set up a robust, modular service (language and framework are flexible) that exposes REST or GraphQL endpoints for authorise, capture, refund, and subscription-style operations. • Implement gateway adapters for PayPal, Stripe, and Square, switching dynamically according to rules I’ll provide (e.g., best fee, currency availability, fallback logic). • Handle multi-currency flows natively in USD, EUR, and GBP, with correct rounding, FX display and gateway-specific quirks accounted for. • Provide straightforward authentication (JWT or similar), webhooks for status updates, and idempotency so front-end teams can safely retry. • Supply concise documentation and a Postman collection so my engineers can plug in quickly, plus unit and integration tests that run in CI. Acceptance criteria 1. A dockerised build spins up the orchestrator, connects to sandbox keys for all three gateways, and completes a full payment flow in each currency. 2. API responses follow the schema we agree on; any deviation blocks sign-off. 3. Codebase is clean, commented, and handed over in a private repo alongside the technical docs. If this sounds like your wheelhouse, let’s talk timeline and hand-off details so I can put this into production without stalling our release calendar.