Short answer: choose the LLM API that gives a Node.js service a clear, testable contract for structured output. For an in-app chatbot that scores candidates against a job rubric, validate every response, log the decision path, retry only safe failures, and keep the rubric outside the model's memory.

The API brand is secondary. A malformed score can move a candidate into the wrong review queue. A slow answer can make a recruiter submit the same request twice.

Criterion Pick this when Verify

Strict structured output A score drives a workflow or database write Required keys, bounds, and refusal behavior

Streaming text The user needs visible progress Partial-message handling and final validation

Batch processing Scoring can wait Job state, replay safety, and correlation

Minimal request The chatbot answers a low-risk question Timeout, retry, and fallback behavior

What should the runtime guarantee?

Start with the decision contract, not the prompt.…