There's no universal right answer here but I'd say if you've only got one senior dev right now, trying to build a payment platform in-house is going to take forever and you'll hit obstacles you didn't anticipate. Payment systems have a lot of hidden complexity around edge cases, security requirements, and regulatory compliance. Your solo dev might be brilliant but there's a ton of domain-specific knowledge that comes from having built these systems before. The risk with outsourcing is ending up with code you don't understand or can't maintain, but that's mainly a problem if you go with the wrong partner. Look for a team that's willing to document thoroughly, do knowledge transfer sessions, and write code that your eventual internal team can work with. Make sure you own all the code and IP from day one. And start planning your transition strategy early - how will you eventually bring maintenance and new features in-house? That transition period is where things often get messy if you haven't thought it through.