Build vs. buy gets treated like a coin flip: pick a side, defend it in the planning meeting, move on. That framing misses the actual decision, which isn’t about the tool at all. It’s about where your organization creates leverage, and where it’s just doing work that a hundred other companies already do better.
Buying a well-run vendor for undifferentiated infrastructure, authentication, payments, observability, is rarely a hard call once you frame it that way. The harder cases are the ones in the middle: a workflow engine that’s almost like the market leader’s, but not quite; a data pipeline that started as a quick integration and grew into a load-bearing system nobody planned to own.
Three questions that cut through most build-vs-buy debates:
- Is this differentiated, or is it plumbing? If a competitor could buy the exact same capability off the shelf, you’re probably not building competitive advantage by writing it yourself.
- What does “owning it” actually cost? Not just engineering time. On-call load, security surface, the opportunity cost of the team that could be doing something else.
- Can you change your mind later? A buy decision with a clean integration boundary is reversible. A build decision that’s deeply wired into the codebase is not. Reversibility should weigh into the decision, not just capability.
Don’t build more technology. Build technology that creates leverage, and buy the rest with a clear conscience. That distinction, more than any specific tool choice, is what separates engineering organizations that move fast from the ones that spend their best people maintaining infrastructure nobody outside the company will ever see.