Structured Output Reliability Across Providers
Schema compliance is a serving-stack property.
- Structured-output validity spans 96.0%–99.8% across 12 providers on the same model.
- 10 of 12 providers expose a native JSON-schema mode; native modes occupy the top of the validity table.
- Validity failures are dominated by schema violations, not JSON syntax — outputs parse but disobey the contract.
The validity table
Measured under the Structured workload: JSON validity, schema compliance and constraint compliance must all pass.
| Provider | Validity | Native schema mode |
|---|---|---|
| Fireworks | 99.8% | yes |
| OpenRouter | 99.2% | yes |
| Nebius | 98.8% | yes |
| Together | 98.5% | yes |
| Groq | 98.4% | yes |
| DeepInfra | 98.4% | yes |
| Cerebras | 98.1% | no |
| SiliconFlow | 98.0% | yes |
| Scaleway | 97.9% | yes |
| Nextbit | 97.6% | yes |
| Mistral | 97.1% | yes |
| OVHcloud | 96.0% | no |
- Prefer providers with native schema enforcement for pipelines that parse machine-readable output — prompt-only JSON is measurably less reliable.
InferenceBench (2026). Structured Output Reliability Across Providers. InferenceBench Research.