Fix JSON Errors — Complete Toolkit
Every kind of JSON breakage has its own purpose-built repair tool. Pick the one that matches your error and fix it in one click.
JSON.parse throws on the first character that breaks the grammar, and the error message rarely tells you which kind of mistake to look for. The tools collected here each focus on one repair: stripping trailing commas, decoding the "Unexpected token" message, detecting duplicate keys, normalizing malformed JSON wholesale, and more. All of them run entirely in your browser — your JSON is never uploaded.
Tools in this collection
JSON Trailing Comma Fixer
Paste broken JSON and instantly remove trailing commas. Free, browser-based, no upload. Fix arrays and objects in one click.
Fix "Unexpected Token in JSON" Errors
Decode the cryptic "Unexpected token in JSON" error and auto-repair the underlying issue. Free, browser-based, no uploads.
Fix Malformed JSON Online
Repair malformed JSON in seconds. Detects unquoted keys, missing brackets, stray commas, and bad escapes. 100% browser-based.
JSON Syntax Error Debugger
Pinpoint JSON syntax errors with line numbers, character offsets, and a recommended fix. Free, browser-based, no upload.
JSON Duplicate Key Checker
Detect duplicate keys inside JSON objects that JSON.parse silently overwrites. Free, browser-based, no upload.
JSON Key Deduplicator
Strip duplicate keys from JSON objects with a single click. Choose to keep the first or last value. Free, browser-based.
JSON Array Duplicate Finder
Find duplicate items inside JSON arrays — by value, by key, or with a custom comparator. Free, browser-based.
JSON Quote Fixer
Convert single quotes, smart quotes, and backticks to JSON-compliant double quotes. Free, browser-based, no upload.
JSON Comment Stripper
Strip // and /* */ comments from JSONC config files to produce strict JSON. Free, browser-based, no upload.
JSON Key Normalizer
Convert all JSON keys to camelCase, snake_case, kebab-case, or PascalCase in one pass. Free, browser-based.