I built a WooCommerce payment SaaS solo. The checkout UI was the easy part 😅

Hey everyone! 👋 I'm a solo developer from Morocco, and I wanted to share something I've been working on for quite a while. It's called GPCB Pay, a WooCommerce payment integration that connects stores with PayPal card payment experiences. When I started, I thought the biggest challenge would be building the card payment interface. Well... I was wrong haha. The real challenge was everything happening behind the scenes. What if PayPal approves a payment but the capture fails? What happens if the network disconnects? What if the same request gets retried? I didn't want a customer getting charged twice or WooCommerce marking an order as paid when it wasn't. So I ended up building three separate systems: - A lightweight WooCommerce plugin using Checkout Blocks. - A private SaaS backend using Node.js and PostgreSQL. - A React dashboard for merchant registration, store verification, PayPal connections, and subscriptions. I spent a lot of time working on idempotency, server-verified captures, duplicate-capture protection, and payment recovery. I also learned that integrating PayPal isn't just about having API credentials. Guest Card and Advanced Card have different eligibility requirements depending on the merchant and country. I've now finished V1, tested the payment flows, and recorded a full setup tutorial showing how the integration works. The next challenge is probably even harder: finding the first real customers haha. I'd love to get some feedback from other solo founders. If you were in my position, would you start by reaching out to WooCommerce agencies or individual store owners? And if you've built a SaaS alone, what was harder for you: building the product or getting people to discover it? Thanks for reading! 🙌