JSON Checker
Every error at once
Parsing recovers after a failure, so six mistakes show up as six findings — not one cryptic token error at a time.
Chrome extension
Check JSON in a side panel
Paste a payload, see every problem in plain English, and fix common mistakes in one click. Everything stays in your browser.
Install the extension
Free · runs fully offline
Plain-English causes
Forgotten commas, invisible characters, and not-JSON payloads are named the way a person would describe them, with the line that actually needs changing.
Repairs with undo
Trailing commas, single quotes, bare keys, comments, and similar slips can be fixed in one click. Data inside strings is never rewritten.
JSON Checker declares no host permissions and makes no network
requests. Payloads stay in
chrome.storage.local. Read the
privacy policy.