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JSON Preflight Checker

Check your JSON against the required schema — and fix it — before you upload it.

1 · Your JSON file

📄

Choose a file or drag & drop it here

One .json file · max 2 MB

…or paste JSON instead

No file handy?

2 · What the schema expects

Loading schema…

The schema lives in schema.json in the app's repository — push a commit to change the rules and auto-deploy rebuilds the app. Backend: FastAPI · validation is deterministic (rule-based) and runs in memory; nothing is stored.

JSON Preflight Checker

1 · Your JSON file

2 · What the schema expects

✓ is valid

🤖 Assistant — how to fix your file, step by step