Use o3 (openai/o3).
This is one of the cases where paying for more reasoning is justified.
~8.6× more per run.
Which AI model should you use to design a microservices API?
Why ->
The task description signals deeper reasoning, trade-off analysis, or risk-heavy judgement. A larger tier earns its cost here because it handles longer reasoning chains and ambiguity more reliably.
Cost breakdown
| Model | Provider | Tier | Input cost | Output cost | Est. / 1k calls |
|---|---|---|---|---|---|
| o3 openai/o3 | Openai | Deep | $0.002000 | $0.008000 | $10.80 |
| GPT-5 Mini openai/gpt-5-mini | Openai | Moderate | $0.000250 | $0.002000 | $1.25 |
Matched signals
- microservices
- design
This recommendation is based on the task description alone. If you are attaching a large codebase, mention it in the input above.
Model pricing: OpenRouter model catalog, retrieved April 17, 2026. Classification: rightmodel ruleset v2.
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