Diff Checker compares two versions of a text or a file and shows the diff: lines that were removed, lines that were added, and inside each changed line the exact words that differ. It works for code, configuration files, logs, documents and lists. The comparison runs in your browser, so your code is never uploaded.
How to check a diff
- Paste the original version on the left and the new version on the right. Or drop a text file on each box.
- Tick Ignore spaces and line indentation for reformatted code, or Ignore case if upper and lower case do not matter.
- Click Compare.
- Read the diff Side by side, or in One column for a compact list of changes.
- Tick Show only changed lines to hide unchanged code around the edits, and Download diff to save it.
Reading the result
| You see | It means |
|---|---|
| Red line on the left | Removed in the new version |
| Green line on the right | Added in the new version |
| Red and green side by side | A changed line; the changed words are highlighted |
| Line numbers | The position in each version |
The summary above the diff counts changed, added, removed and unchanged lines.
For developers
- Config files: find the setting that differs between a working and a broken environment, such as two
.env.example, YAML or INI files. Remove real secrets first. - Reformatted code: with Ignore spaces and line indentation on, a file that was re-indented or switched from tabs to spaces shows only the lines that really changed.
- JSON: format both versions with the same indent and sorted keys in the JSON Formatter, then compare. Keys in a different order no longer show as changes.
- Logs and output: compare the output of two runs to spot the line where they part ways.
- Sharing a change: download the diff as a text file and attach it to a ticket or a message.
Also for writing
The same diff works for prose. Paste two drafts of an article, a contract or a translation, and the changed words are highlighted inside each sentence, so even a single comma stands out. For more tips on documents, see Text Compare.
Good to know
Diff Checker compares plain text. Formatting such as bold, fonts or layout is not compared. To compare Word or PDF documents, copy their text out first, for example with PDF to Text.