Tools
Text diff checker
Compare two blocks of text line by line. Paste the original and the changed version below to see a unified diff (added lines in green, removed lines in red, and unchanged lines as context) with a running tally of how many lines were added and removed. Everything runs in your browser; your text is never uploaded or stored.
A private, in-browser diff for code, configs, and logs
A diff (short for “difference”) shows exactly what changed between two versions of text. Developers reach for one constantly: reviewing a code change, spotting a stray edit in a config file, comparing two log outputs, or checking what a formatter rewrote. This tool computes a line-level diff with a longest-common-subsequence algorithm, the same foundation used by tools like git diff, so the result is the minimal, intuitive set of changes rather than a naive line-by-line mismatch.
Because it is entirely client-side, it is a safe place to compare text you would never paste into a random website: environment files, API responses, stack traces, or production logs. Nothing leaves the tab. Paste, read the diff, close the tab, and there is no trace left behind.
Frequently asked questions
- How does this text diff tool work?
- It splits both inputs into lines and runs a longest-common-subsequence (LCS) algorithm (the same core technique behind git diff) to find the smallest set of additions and removals that turns the original into the changed version. Matching lines are shown as context, added lines are green, and removed lines are red.
- Is my text uploaded anywhere?
- No. The entire comparison runs in your browser using JavaScript. Nothing is sent to a server, logged, or stored. You can even disconnect from the network and it still works. That makes it safe for diffing configs, logs, or snippets that contain sensitive data.
- Does it handle Windows and Unix line endings?
- Yes. CRLF (\r\n) and lone CR line endings are normalized to LF before comparison, so a file saved on Windows and one saved on macOS or Linux will not report every line as changed just because of line-ending style.
- Is there a size limit?
- To keep the tool responsive in the browser, each side is capped at 5,000 lines. If either input is longer, the extra lines are ignored and a notice is shown. For very large files, diff locally with git or a desktop diff tool.
- What do the + and - counts mean?
- They are the number of added lines (present only in the changed text) and removed lines (present only in the original). A line that was edited shows up as one removal plus one addition, which is how unified diffs represent in-place changes.