Data format toolkit
JSON Validator
Checks whether your JSON is valid, and when it isn't, explains why in plain English — a trailing comma, single quotes instead of double, an unquoted property name — with the exact line and column, instead of just “Unexpected token at position 45”.
Pricing
Free for one-off conversions. Pro for daily use.
Occasional use is free, forever. If you're converting files at work every day, Pro pays for itself in the first ten minutes you save.
Free
For occasional, one-off conversions.
- Convert, validate, format, diff, JSONPath, schema generate + validate
- Files up to 256 KB
- One file at a time
- Runs entirely in-browser
Pro
For daily conversions, CI use, and larger files.
- Everything in Free
- Files up to 25 MB
- Batch convert — up to 100 files at once, download as .zip
- Saved presets — reusable delimiter/format settings
- No ads
- Priority support
API
For scripts, pipelines and internal tools.
- Everything in Pro
- REST API with your own key
- 10,000 conversions / month
- Webhook + CLI available
- Team seats (add-on)
API
Convert from your scripts and pipelines.
Same conversions as the browser tool, available over a simple REST API. Ideal for backends, CLIs, and internal tools. Prefer zero network dependency? The recast-cli npm package runs the identical engine locally.
Recast API — early access
The API is in private beta. You'll get a personal key, 10,000 conversions per month, support for all conversion, diff, and schema modes, and webhooks.
POST /v1/convert
Authorization: Bearer rk_live_••••••••
Content-Type: application/json
{
"mode": "json2csv",
"input": "[{\"id\":1,\"name\":\"Ada\"}]",
"options": { "delimiter": ",", "excel_bom": true }
}
Planned endpoints: /v1/convert,
/v1/diff,
/v1/schema,
/v1/me,
/v1/usage