Practical guide
How to use Text Diff
Text Diff compares two versions line by line. It is useful for drafts, configuration snippets, generated output, and notes where a full source-control system would be excessive.
Step by step
- Paste the original and updated versions.
- Choose whether surrounding whitespace should be ignored.
- Compare the texts and read additions, removals, and unchanged line numbers.
Example
Original: Fast tools
Updated: Fast local tools1 removed line; 1 added lineHow it works
The tool computes a longest common subsequence of lines, then presents unmatched original lines as removals and unmatched updated lines as additions.
Important limitations
- A changed line is represented as a removal followed by an addition rather than a character-level edit.
- Very large comparisons are limited to protect the browser from excessive memory use.
Real workflows
When this tool is useful
Editorial revision
Compare two drafts to see which complete lines were inserted or removed before accepting a rewritten section.
Generated output
Check whether a template, prompt, or export changed across runs without committing temporary files to source control.
Configuration notes
Review small plain-text settings or lists where line order matters and a structured JSON comparison is not appropriate.
Review the result
What to check before using the output
A line-level diff can make a small edit look like one removed line and one added line. Inspect neighboring lines and intentional reordering before concluding that content was deleted.
- Confirm which side is original.
- Choose whitespace behavior deliberately.
- Review moved lines separately.
- Save important history in source control.
Choose the right method
When another tool is better
Use JSON Diff for structured objects, a word-level editor for prose collaboration, and source control for project history, authorship, merging, and reproducible review.
Privacy and browser behavior
Both versions remain in memory in the tab. Replace customer data and credentials with synthetic content before using a comparison in a public demonstration or issue report.
Frequently asked questions
Can it ignore all whitespace?
The current option ignores surrounding whitespace only; internal spaces remain significant.
Does it upload both documents?
No. Comparison is calculated in the active browser tab.