2026-09-08
Comparing two versions of a config file, a code snippet, or a block of text by eye is slow and unreliable past a few lines — a diff tool that highlights exactly what changed is one of those small utilities that saves real time, if you're comfortable pasting both versions into it.
| Tool | Line-by-line highlighting | Handles large text blocks | Runs fully in your browser | Account required |
|---|---|---|---|---|
| iLoveDevTools | Yes | Yes | Yes | No |
| Diffchecker | Yes | Yes | No (server round-trip) | No for basic use |
Code Diff Viewer compares two blocks of text or code and highlights additions and deletions clearly, computed entirely in your browser — useful when at least one of the two versions contains something you'd rather not send to a server, like a config file with real credentials.
The most well-known name in this category, with a clean, fast interface and support for comparing images and PDFs in addition to text. Both inputs are sent to their servers to compute the diff.
For comparing sensitive text or config content, iLoveDevTools keeps both versions local. Diffchecker's broader format support (images, PDFs) is useful if you need comparison beyond plain text.