In brief
- Start from the product failure you cannot tolerate.
- Use a small representative evaluation.
- Preserve switching ability at the client boundary.
Begin with the product contract
Define what the model must do, the response time users will accept, what errors are recoverable, and where a human remains in the loop. Model choice follows this contract.
Shortlist by capability
Filter on modality, context, tool use, structured output, availability, and policy requirements before comparing style or price.
Run a small matched pilot
Use real task shapes, hide candidate identity during review, and track success plus operating cost. A startup rarely needs a huge benchmark to avoid an uninformed choice.
- Ten to thirty representative cases can reveal obvious mismatches
- Include edge cases and refusals
- Measure the user-visible outcome
- Keep raw artifacts for review
Keep the architecture reversible
Put model IDs and parameters in configuration, isolate the client, and log resolved identity. Avoid building provider-specific behavior into every feature until the benefit is proven.
Frequently asked
Questions, answered plainly.
Should a startup use the strongest model available?+
Use the model that clears the product quality bar with acceptable latency and task cost. The strongest general model may be unnecessary for every request.
Is multi-model routing necessary at launch?+
Usually not. One evaluated default plus a tested fallback is easier to operate. Add routing when task data shows a meaningful benefit.
How can a startup avoid provider lock-in?+
Use a stable application boundary, externalize model configuration, keep evaluations portable, and avoid relying on proprietary features without a clear payoff.
Sources and next paths