Pick an AI API your product can grow with.
There is no universal best API for a startup. The useful choice handles your work reliably, fits your operating needs, and leaves room for the product to change.
Test your awkward examples
Build a small evaluation set from realistic inputs, including incomplete and messy ones. Decide what a passing answer looks like before comparing providers. Measure accuracy, latency, and failure behavior together.
Look at the account limits
Confirm throughput, model access, regional requirements, and billing controls. Try the integration path your team can maintain. An inexpensive API becomes costly if developers must build a large workaround around it.
Leave room to change
Keep provider-specific code behind a small interface when practical. Budget for normal billing, not just free trials. Choose credits that fit tested demand and a usable expiry window, rather than tying your roadmap to an attractive but restricted account.