Patch Viewer
Create, summarize, and apply unified diffs / patches in the browser.
About this tool
Create, summarize, and apply unified diffs / patches in the browser. Useful when reviewing API responses, cleaning config before commit, or sharing readable snippets in docs and PRs.
Choose Create to build a unified diff from Original vs Modified text. Use Summarize to count additions/deletions in a pasted patch. Example — Create a one-line change patch: try `Original: hello world Modified: hello world!` and expect something like `--- a/file.txt +++ b/file.txt @@ ... @@ hello -world +world!`.
Apply works best for single-file patches with matching context lines. See also: Text Diff, and JSON Diff. Runs in your browser — nothing you paste gets uploaded.
How to use
- Choose Create to build a unified diff from Original vs Modified text.
- Use Summarize to count additions/deletions in a pasted patch.
- Use Apply to replay a single-file unified diff onto Original text.
- Copy the Output when sharing a patch in review or applying locally.
Example
Create a one-line change patch
Input
Original: hello world Modified: hello world!
Output
--- a/file.txt +++ b/file.txt @@ ... @@ hello -world +world!
Limitations
- Apply works best for single-file patches with matching context lines.
- Multi-file git patches may fail to apply cleanly in the browser.
- This is not a three-way merge tool — conflicts are not interactively resolved.
Related guides
1Related tools
2Frequently asked questions
What does the Patch Viewer do?
Create, summarize, and apply unified diffs / patches in the browser. Runs in your browser — no install, no account.
How do I use the Patch Viewer?
Choose Create to build a unified diff from Original vs Modified text. Use Summarize to count additions/deletions in a pasted patch. Use Apply to replay a single-file unified diff onto Original text. Copy the Output when sharing a patch in review or applying locally.
Is the Patch Viewer free?
Yes. No signup, no usage limits, no paywall.
Does the Patch Viewer upload my data?
No. Processing happens locally in JavaScript. Your input is not uploaded, stored, or logged.
What are the limitations of the Patch Viewer?
Apply works best for single-file patches with matching context lines. Multi-file git patches may fail to apply cleanly in the browser. This is not a three-way merge tool — conflicts are not interactively resolved.