JSON Validator — Find Errors Fast
A dedicated validator that focuses on one job: telling you whether your JSON is valid, and if not, exactly where the problem is. Ideal for triaging API responses and config files.
Last updated: · Runs 100% in your browser
Result will appear here.// What is the JSON Validator?
The JSON Validator answers a single question as precisely as possible: is this document valid JSON, and if not, where exactly does it break? It runs your input through a strict RFC 8259 parse and reports the first failure with a line and column marker, plus the offending character, so you can jump straight to the missing comma, the smart quote your word processor inserted, or the trailing bracket that a copy-paste truncated. Unlike a formatter, it does not attempt to rewrite anything — validation is non-destructive, which matters when you are checking a file you intend to ship byte-for-byte. Validation happens entirely in your browser, so config files containing connection strings or credentials never leave your machine.
// Features
- ▸Instant valid/invalid verdict
- ▸Line and column error markers
- ▸Trailing character detection
- ▸Zero network round-trips
// How to use
- 01Paste your JSON into the input pane.
- 02Read the verdict banner at the top of the output.
- 03If invalid, jump to the reported line/column and fix.
// Use cases
- ▸Checking a hand-edited config file before deploying it.
- ▸Triaging a webhook payload that a downstream service rejected.
- ▸Confirming a generated export is parseable before importing it elsewhere.
- ▸Teaching or reviewing JSON syntax with immediate, precise feedback.
// FAQ
Your data never leaves your browser. This tool runs 100% locally — no upload, no logging, no analytics on your inputs.