Online Code Diff Tool
Compare two code snippets side by side, see every added and removed line, and let AI explain what changed and why.
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| 1 | 1 | function getUserName(user) { | |
| 2 | - | if (user !== null) { | |
| 3 | - | if (user.name !== undefined) { | |
| 4 | - | return user.name; | |
| 5 | - | } else { | |
| 6 | - | return 'Anonymous'; | |
| 7 | - | } | |
| 8 | - | } else { | |
| 9 | - | return 'Anonymous'; | |
| 10 | - | } | |
| 2 | + | return user?.name ?? 'Anonymous'; | |
| 11 | 3 | } |
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How to read diffs
About this tool
Code Diff
A code diff tool compares two pieces of text or code and shows you exactly what changed: which lines were added, removed, or modified. Paste an original version on one side and the updated version on the other to get an instant, readable line-by-line comparison.
Beyond highlighting the changes, this tool can explain a diff in plain English with AI, which is handy for reviewing pull requests, understanding someone else's edit, or writing a clear commit message. It works entirely in your browser and is free on the HACKUP Free plan.
Frequently asked questions
Code Diff FAQ
- What does a code diff tool do?
- It compares two versions of text or code side by side and highlights every difference, showing added, removed, and changed lines so you can see exactly what changed.
- Can I diff any kind of text?
- Yes. While it is built for source code, you can compare any plain text, logs, configuration files, or JSON, and the line-by-line comparison works the same way.
- Does it explain the changes?
- Yes. The AI explainer can summarize a diff in plain English, which is useful for code reviews and for understanding unfamiliar changes.
- Is my code uploaded anywhere?
- The diff itself is computed in your browser. AI explanations are optional and only sent when you explicitly request them.