Diff Checker
Compare two blocks of text or code line by line and see exactly what was added, removed and left alone.
Compare two blocks of text line by line and see exactly what was added, removed or left alone.
Difference
3 added, 3 removed
- const timeout = 5000;
+ const timeout = 8000;
const retries = 3;
- export function load(url) {
- return fetch(url);
+ export async function load(url) {
+ return fetch(url, { signal });
}About the diff checker
A diff answers one question: what actually changed. Comparing two versions by eye works for a few lines and fails completely past that, because the moment one line is inserted every line below it looks different even though nothing about it moved.
This tool uses a longest common subsequence match, which is the same approach git uses. It finds the smallest set of real changes rather than reporting everything after an insertion as modified. Both versions stay in your browser, so you can compare a config file or a contract without it being uploaded.
How to use it
- 1Paste the original version on the left.
- 2Paste the changed version on the right.
- 3Turn on whitespace or case insensitivity if those differences are noise for you.
- 4Read the highlighted result: green is added, red is removed.
- 5Copy the unified diff, or switch to the changes only view.
Questions
Is my text uploaded?
No. The comparison runs entirely in your browser, so nothing is transmitted or stored.
Why does ignoring whitespace matter?
Reindenting a block changes every line it touches. With whitespace ignored, those lines stop showing as changes and the real edits become visible.
Can it compare code?
Yes. It is line based, which is what you want for source code, config files, logs and CSV. It does not understand syntax, so a reformatted line reads as a change.
Is there a size limit?
Comparison is capped at 1500 lines per side. Beyond that a browser based diff gets slow enough to be unpleasant, and a real diff tool is a better fit.