Payments
Only add this if payments are core to your value prop.
Payments are a credibility signal when they're core to the concept — a marketplace, a subscription tool, a fintech project. Judges understand the business model immediately when they see Stripe integrated correctly. But payment integration is time-intensive and error-prone under time pressure. Only add it if the project doesn't make sense without it.
Don't add payments as an afterthought to show 'monetization potential.' It takes time you don't have and adds complexity to your demo. Use Stripe's test mode — never real cards in a hackathon.
Stripe for everything if you need card payments. LemonSqueezy if you want a simpler API for digital products. Always use test mode. Always have a fallback demo flow if the payment integration breaks during the presentation.