Text comparison tool
Compare two texts side by side and spot every added, removed, or changed line. Nothing leaves your browser.
Private · compared in your browser
Deleted lines appear here in red.
Additions and modifications appear on this side.
This online diff checker places an original text beside a changed version and marks deleted lines in the original while showing additions and modifications in the changed text. Related edits receive a focused inline highlight, while substantially different lines are marked as complete changes instead of producing distracting character fragments.
Paste content directly or load two local text files, then use the added, removed, and changed totals for a quick summary. The synchronized editors are useful for reviewing source code, configuration, logs, drafts, generated output, API responses, and any other plain-text content. The overview ruler beside the right scrollbar shows where changes occur across the whole document and lets you jump directly to them.
Both inputs stay in your browser. The page performs the line-level and character-level comparison with local JavaScript and does not upload your text to a backend comparison service. The content is not added to the URL or saved by this tool, which makes it a practical choice for internal notes and everyday development work.
Use the fullscreen control for focused reviews, swap the two sides when you want to reverse the comparison, or clear both editors when you are finished.
Line-level highlighting shows which complete lines were added, removed, or modified. Closely related modified lines also receive a focused inline highlight, while substantially different lines are marked as complete changes to keep the result readable.
No. Both texts are compared locally by JavaScript in your browser. They are not uploaded to afsalv.com, placed in the page URL, or saved by the tool.
You can load ordinary text-based files such as TXT, Markdown, JSON, CSV, XML, YAML, source code, configuration files, and logs. Binary formats such as PDF, Word, and images are not supported.
Yes, within a browser-friendly limit of 500,000 characters and 20,000 lines per side. The comparison also has a short processing timeout so unusually difficult inputs cannot freeze the page.
The comparison runs locally and the tool does not send your text to a comparison service. You should still follow your organisation's rules for handling confidential information and use a trusted device and browser.
Removed lines appear in red on the original-text side, while additions are green and modifications are amber on the changed-text side. The overview ruler beside the right scrollbar shows where each change occurs across the document.