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Structured Outputs Across LLM Providers: 244 Models Tested (2026)

calendar_today May 30, 2026 person domain requesty

We tested structured outputs (json_schema) across 244 models, 23 providers, 3 endpoints, and 10 popular SDKs. Over 2,400 tests. Here is the full compatibility matrix, what works, what breaks, and how to get consistent JSON schema enforcement without rewriting your integration for every model.

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