Free online file difference and code difference checker
The Erapse File and Code Compare Tool is built for quick, browser-based comparison when you need to check the difference between two files, two code snippets or two blocks of plain text. Paste the original content on the left, paste the changed content on the right, then run the comparison to see unchanged lines, changed lines, added lines and removed lines in a clear side-by-side view. It is useful when you want a free online file compare tool without installing desktop software for a simple review.
A file difference check is especially helpful before you copy new code into a project, update a configuration file, review a JSON response, compare XML settings, check a CSV export, inspect a log file or verify a documentation change. Instead of reading both files from top to bottom, the tool highlights the exact areas that need attention. Changed text inside a line is also marked, so a small code difference such as an added variable, changed number, missing comma or edited word is easier to notice.
How the compare result works
The left side shows the original file or original text. The right side shows the changed file or changed text. When a line exists only on the right, it is treated as an added line. When a line exists only on the left, it is treated as a removed line. When both sides have a line in the same position but the characters are not identical, the page marks that row as changed and highlights the changed part inside the line. This makes the file difference view useful for code review, content review and text proofreading.
The word summary option gives a lighter view of removed and added word occurrences. Use line compare when you are checking source code, JSON, XML, CSS, HTML, SQL, CSV or logs. Use word summary when you want a quick text difference check for paragraphs, notes, article edits, product descriptions or short documentation changes.
Useful use cases
- Compare old and new source code before pasting it into a project.
- Check code difference in JavaScript, CSS, HTML, SQL, PHP, Python, Java, TypeScript or similar text-based files.
- Review JSON difference after changing an API response, app setting or package configuration.
- Compare XML difference for sitemap, feed, app configuration or markup changes.
- Check CSV file difference after exporting data from a spreadsheet or admin panel.
- Compare two log files to identify newly added errors or missing entries.
- Review article, policy, invoice template or documentation changes before publishing.
Common mistakes while comparing files
One common mistake is comparing formatted and minified files together. For example, a minified JSON file and a pretty JSON file may contain the same data but appear very different because line breaks and spacing changed. If you are comparing JSON, format both versions first with the JSON Formatter, then come back to this file diff checker. The same idea applies to XML, HTML and CSS: cleaner formatting usually gives a more readable difference result.
Another mistake is ignoring small punctuation changes. In code, a missing comma, bracket, quote, semicolon or minus sign can change behavior. In CSV files, one extra comma can shift columns. In configuration files, one changed value can affect a full application. Always read the highlighted code difference carefully before using the changed file in a live project.
Privacy and file handling
This page is designed as a browser utility for text-based comparison. The comparison runs on the page after you paste or select text files. Do not use confidential production secrets, private keys, passwords, customer records or sensitive company files on a shared computer. For very sensitive code or private business documents, use your approved internal tools and follow your organization rules.
Limitations
This file compare tool is made for text files and code snippets. It is not designed for binary files such as images, videos, compressed archives, Word documents or PDFs. Very large files may be limited by browser memory and device speed. The comparison is line-focused, so moved blocks can appear as removed and added instead of being recognized as one moved section. For complex software repositories, a full developer diff tool or version control system may still be better.