Compare two texts and highlight differences
The MailDrop text diff tool compares two blocks of text and highlights exactly what changed between them. Paste the original version on the left, the modified version on the right, and click Compare. The tool aligns the two texts line by line using a longest-common-subsequence algorithm, then marks added lines with a plus sign and removed lines with a minus sign, color-coded so differences jump out at a glance.
Spotting changes by eye is slow and unreliable, especially in contracts, configuration files, articles, or email templates where a single altered word can matter. A diff view answers the question instantly: what exactly is different between these two versions? Because the comparison runs entirely in your browser, you can safely diff sensitive material like legal text or private notes; nothing you paste is uploaded, stored, or logged anywhere.
The tool is free and requires no registration or account. It belongs to the same privacy-minded toolkit as MailDrop temporary email: useful everyday utilities that work without asking who you are, ideal for quickly checking whether a terms-of-service update or newsletter template actually changed.
Put the first version of your text, such as the older document, the pre-edit draft, or the previous config file, into the Original Text box on the left side.
Put the second version into the Modified Text box on the right. The tool compares whole lines, so texts with natural line breaks, like code, configs, or lists, produce the clearest results.
Click Compare. The algorithm matches the largest common structure between both versions and renders a unified view where unchanged lines stay plain, deletions are marked with a minus, and additions with a plus.
Scan the color-coded output to see every insertion and removal in context. If the two texts are identical, the tool says so explicitly, which is itself a useful confirmation before publishing or deploying.
No. The entire comparison is computed by JavaScript in your browser; your text never leaves your device. That makes the tool safe for confidential material such as contracts, credentials files you are auditing, or unpublished writing. Closing the tab removes every trace.
It computes the longest common subsequence of lines between the two texts, which finds the largest amount of content the versions share in the same order. Everything outside that shared backbone is reported as either a deletion from the original or an addition in the modified version.
Line by line. Each line is treated as a unit, so a line with even a one-character edit shows up as one removal plus one addition. For prose in a single long paragraph, adding line breaks at sentence boundaries before comparing produces a much more readable diff.
Common cases include reviewing edits to documents and contracts, checking what changed between versions of a configuration file, verifying an email template before it goes out, comparing API responses, and confirming that a copied text matches its source. Anywhere two versions exist, a diff shows the delta faster than reading both.
Yes, and it is a neat trick. Copy the body of two messages from your MailDrop disposable email inbox, for example two versions of a newsletter or two verification emails from different signups, and paste them here to see precisely what the sender changed or personalized between them.