Diff Checker
Spot colourful line and word changes in text, JSON, source code and more. No uploads.
Processed locally in your browserPreparing comparison…
How to use Diff Checker
- Paste original and changed content or open UTF-8 files. Choose text, JSON, JavaScript, TypeScript, HTML, XML, CSS, CSV, YAML, Markdown, SQL, Python, INI or TOML.
- Compare in a local worker. JSON can be normalized and object keys sorted without rounding number literals. Optional ignore-case and edge-whitespace settings affect visual matching.
- Choose side-by-side or unified view, navigate changes, filter unchanged rows, and copy or download a unified patch. Large results are paged.
Useful things to know
This is line/word text comparison, not a semantic parser, executable-code analyser, CSV table merge or JSON Patch generator. Only JSON normalization validates syntax; duplicate keys and excessive nesting are rejected. Input is capped at 200 KB and 5,000 lines per side, with algorithm and worker deadlines. CRLF/CR endings are normalized to LF; JSON formatting/key order can be normalized before patch generation. Downloaded patches reflect all prepared-text changes, including ones ignored in the visual view. Inline word highlights are bounded and fall back to whole changed lines on large edits. Text is displayed safely rather than interpreted as HTML.
Is Diff Checker free, and how is my privacy handled?
Yes. Diff Checker is free to use without registration. Tool inputs are processed in your browser rather than uploaded to our servers. Optional usage analytics follows your cookie preferences; it does not receive your files or tool inputs. Keep your browser updated and review results before sharing.