JSON Output Guard

Guardrail for AI JSON outputs: extract JSON, parse, and validate against schema before downstream use.

Validation passed. Output is schema-compatible.

Parsed JSON payload

{
  "title": "Sprint plan",
  "priority": "high",
  "tasks": [
    {
      "id": "t1",
      "text": "Design API",
      "done": false
    },
    {
      "id": "t2",
      "text": "Write tests",
      "done": true
    }
  ]
}

About This Tool

JSON Output Guard is a reliability layer for AI workflows that expect structured outputs. It extracts JSON from model responses and validates shape before passing data to production code.

Frequently Asked Questions

Does it support full JSON Schema spec?

No. It supports a practical subset used by most AI output contracts.

Can it parse fenced JSON blocks?

Yes. It tries full text first, then JSON code blocks, then brace extraction.

Is output text uploaded?

No. Validation runs locally in your browser.

Related Tools

JSON Schema Validator
Validate JSON data against a JSON Schema. Check types, required fields, and constraints.
Prompt Linter
Lint prompts for ambiguity, missing constraints, and conflicting instructions.
Function Calling Schema Tester
Test tool-call arguments against function schema and catch validation failures early.

Compare With Similar Tools

Decision pages to quickly see when to use each tool.

Output Contract Tester vs JSON Output Guard

General output contract checks vs JSON-specific schema validation.

JSON Output Guard vs Function Calling Schema Tester

Strict JSON output schema safety vs tool/function argument payload schema validation.

Workflow Links

Suggested step-by-step tools based on this page intent.

Before This Tool

Output Contract TesterValidate model outputs against contracts: JSON format, required keys, forbidden terms, and length.AI Reliability ScorecardScore prompt quality, safety, output contract fit, and replay-test risk before release.TOML ↔ JSON ConverterConvert between TOML and JSON formats. Validate TOML syntax and see parsed output.

Next Step Tools

Output Contract TesterValidate model outputs against contracts: JSON format, required keys, forbidden terms, and length.Prompt Security ScannerScan prompts for secret leakage, PII, and injection-style phrases before sending to AI.Prompt Injection SimulatorSimulate prompt-injection attacks and score guardrail resilience before release.