Instapay Online Payment Gateway

I am building Instapay, a full-featured online payment gateway, and I need an experienced developer to take it from concept to production-ready code. The gateway must reliably process both one-time charges and recurring subscription transactions, exposing clear rest/json apis that can be dropped into web and mobile front-ends with minimal effort.

Core objectives:

Securely collect card and alternative payment data, tokenise it, and forward authorisation requests to acquiring banks/processors.
Handle subscription logic server-side, including automated renewals, retries, and customer notifications.
Provide a clean merchant dashboard that tracks transaction history, payout schedules, and real-time status.
Deliver well-documented api endpoints, webhook events, and sdk snippets (php or node preferred, but i’m flexible).

What would make the build even better—but I’m happy to discuss trade-offs—are multi-currency handling, advanced fraud-screening hooks, and support for popular wallets.

Acceptance criteria:

1. Successful end-to-end test transactions for single and recurring payments on a sandbox account.
2. owasp-compliant code review and evidence of pci-dss best practices.
3. Deployment scripts for staging and production environments.

If you’ve engineered similar gateways or integrated with Stripe, Adyen, or PayPal’s REST APIs, please share links or repos so I can gauge code style and architecture choices. Looking forward to collaborating on a robust, developer-friendly Instapay solution.