Text Diff Checker
Compare two texts side by side. Additions, deletions and changes highlighted instantly — all in your browser.
How to Use the Text Diff Checker
What is a text diff checker?
ToolsPix Diff Checker compares two blocks of text line by line and highlights exactly what changed between them — added lines, removed lines, and modified lines with word-level precision. Everything runs in your browser; nothing is uploaded.
How to compare two texts
Paste your original text into the Original Text panel and the updated version into the Modified Text panel, then click Compare. The diff result appears immediately below with a stats bar showing counts of added, removed, changed, and unchanged lines.
Understanding the results
- Green rows (+ prefix) — lines present only in the modified text.
- Red rows (− prefix) — lines present only in the original text.
- Yellow rows — a line was modified; the red version is the original and the green is the replacement, with exact word-level changes highlighted inline.
- Unchanged rows — identical lines shown as context.
What can I compare?
Any plain text works: source code, JSON, Markdown, SQL, HTML, config files, log output, and prose. For very long documents, compare section by section — each panel supports up to 3 000 lines.
FAQ
Is my text sent to a server?
No. ToolsPix Diff Checker runs entirely in your browser. Your text is never transmitted to any server, never logged, and never stored anywhere outside your device.
What algorithm does this diff tool use?
It uses the Longest Common Subsequence (LCS) algorithm — the same approach used by git diff — to find the minimal set of line-level changes. Consecutive delete/add pairs are then compared word-by-word to highlight inline changes.
What do the diff colors mean?
Green rows are lines added in the modified text. Red rows are lines removed from the original. Yellow rows indicate a line was modified — the removed version is shown in red and the updated version in green, with word-level highlights marking the exact changes.
Can I use this to compare code files?
Yes. The diff checker works with any plain text: source code, JSON, Markdown, HTML, log files, SQL scripts, and prose. Just paste both versions and click Compare.
Is there a limit on text size?
Each panel supports up to 3 000 lines to prevent browser slowdowns on large inputs. For larger files, split the text into sections and compare each section separately.