Diff Two Strings
Highlight what changed between the first two lines of your input. Runs entirely in your browser, so your data never leaves your device.
0 chars · 0 lines
Output
The result appears here as you type.
How to use Diff Two Strings
- 1. Paste two lines to compare. Enter your first string on the first line and the second string on the second line of the input pane; only these two lines are compared.
- 2. Read what the highlighting means. The tool computes the longest common subsequence between the two lines and highlights insertions and deletions, letting you see exactly what changed between them.
- 3. Review the highlighted diff. The output panel renders the two strings with changes visually marked, so you can quickly spot which characters were added, removed, or kept the same.
When to use Diff Two Strings
Diff Two Strings highlights what changed between the first two lines you paste, marking insertions and deletions visually. It gives a fast, character-level comparison when a full file diff tool would be overkill.
- Comparing two versions of a short config value. You have an old and new value for a config setting or environment variable and want to see exactly which characters changed between them before applying an update.
- Spotting a subtle typo between two similar strings. Two API keys, hashes, or identifiers look almost identical, and diffing them character by character reveals the single character where they actually differ.
- Reviewing a small copy edit. An editor changed a single sentence in a document and you want to see precisely which words were altered without scrolling through the whole file's diff.
- Checking a find-and-replace result. You ran a find-and-replace operation and want to confirm exactly what changed between the original and modified line before committing the edit elsewhere.
Examples
Compare two lines
Input
kitten sitting
Output
(highlighted diff)
About the Diff Two Strings tool
Diff Two Strings runs as plain JavaScript in your browser tab, with no server behind it. Highlight what changed between the first two lines of your input. Whatever you put in stays on your device from start to finish.
The tool is part of EditSafely's String Tools section, 159 single-purpose utilities built around the same idea: open the page, get the result, keep your data to yourself.
There is nothing to configure. Provide the input and the result appears on its own. A worked example further down the page shows exactly what the tool produces for a real input.
That local-first design has practical benefits beyond privacy. The tool keeps working on a flaky connection once the page has loaded, results are instant because nothing round-trips to a server, and it is safe to use with confidential material.
Frequently asked questions
Does Diff Two Strings cost anything?
Yes, it is completely free. All 2,658 tools on EditSafely work without an account, a subscription or usage limits.
Is it safe to paste sensitive or confidential data?
No data leaves your device. The whole tool is JavaScript that runs inside your browser tab, so there is no upload, no server-side processing and no log of what you did. If you disconnect from the internet after the page loads, it keeps working.
How much text can I process at once?
There is no fixed limit. Because the work happens on your own device rather than on a shared server, the practical ceiling is your machine's memory, which comfortably handles inputs far larger than typical online tools allow.
Do I need to sign up or install anything?
Nothing to install and no account needed. Open the page in any up-to-date browser, including on a phone or tablet, and the tool is ready.
Can I save what the tool produces?
Yes. Use the download or copy controls in the output panel to keep the rendered result once it looks the way you want.