Online Git Patch and Diff Viewer for Visual Code Review

Direct answer: The quickest way to view a Git patch online is to open a pull request’s Files changed tab on GitHub, where you can switch between unified and split layouts, hide whitespace changes, filter files, navigate with a file tree, and comment on lines. If you only have patch text or a .diff/.patch file, use a standalone online Git diff and patch viewer that accepts that format. For private or sensitive code, inspect the viewer’s privacy and retention policy before uploading anything.

This guide explains each workflow, shows how to generate compatible patches, and gives you a repeatable review process. It also covers merge-base differences, large patches, whitespace noise, binary files, and ways to automate visual captures of review pages.

What an online Git diff viewer shows

A diff describes how one version of a file changes into another. Lines added to the new version are usually shown in green, removed lines in red, and unchanged context around them helps reviewers understand the edit. A patch is a transferable representation of those changes. Git-based tools generate unified diff (unidiff), which the Git project describes as its preferred format for submitting changes.

Most viewers expose two layouts:

• Unified: the old and new lines appear in one stream, prefixed with markers such as + and -. It works well on narrow screens and in terminal output.
• Split or side-by-side: the old file is on the left and the new file is on the right. This makes moved or edited lines easier to scan when both versions fit on screen.

A visual diff is not the same as a complete code-review workflow. A pull request also connects the change to commits, automated checks, discussion, review decisions, merge status, and the proposed base branch.

Choose the right way to view a patch

Situation	Best workflow	What you get
Code is already in a repository and needs approval	GitHub pull request	Files changed, comments, suggestions, checks, history, and merge context
You received patch text or a file	Standalone online viewer	Fast visual rendering without creating a repository or pull request
You need repeatable or private inspection	Git command line or editor	Local processing, scripting, and no third-party upload
You compare patch sets in a review system	Gerrit	Side-by-side review against a selected base or another patch set

View a Git diff in a GitHub pull request

GitHub’s pull-request view is usually the most useful choice when the change is part of team review. Its Files changed tab displays the proposed file changes and provides review controls.

1. Open the pull request in your repository.
2. Select Files changed.
3. Use the layout control to choose unified or split view.
4. Enable the whitespace control when formatting changes obscure the logic.
5. Use the file tree or file filter to jump to a relevant path.
6. Hover a line and select the comment control to start a review comment.
7. Use GitHub’s suggestion feature when you can express the fix as an edit.
8. Submit a review as a comment, approval, or request for changes.

Review the base carefully. GitHub documents that compare pages and pull-request pages can calculate changed files from different merge bases. If a file appears or disappears unexpectedly, inspect the branches, commits, and comparison base before assuming the diff is wrong.

Useful GitHub review controls

• File filtering: narrow the list to a directory, extension, or filename so generated files do not dominate the review.
• Whitespace hiding: remove indentation-only noise while checking that formatting changes did not hide a functional edit.
• Viewed markers: mark files as viewed, then return to the unreviewed set after a break.
• Line comments: anchor a question or finding to the exact changed lines.
• Suggested edits: propose a small replacement that the author can apply from the conversation.

Generate a patch you can open online

Generate a standard unified patch from the command line:

git diff main...feature/login > login.patch

The three-dot form compares the feature branch with the merge base of main and feature/login, which usually matches pull-request intent. To compare two specific commits:

git diff 1a2b3c4 5d6e7f8 > change.diff

For a commit series suitable for email or a patch queue, use:

git format-patch --stdout main..feature/login > series.patch

Inspect the generated file before uploading it. It can contain source code, paths, usernames in headers, and removed secrets that remain visible in deletion lines.

Use a standalone online Git diff and patch viewer

A standalone viewer is useful when you do not control the repository or only need a quick visual inspection. SharePatch says its service accepts pasted diff text, an editable file upload, a raw URL, GitHub pull-request pushes, unified Git diffs, .diff and .patch files, git format-patch output, patch series, and raw patch URLs up to 1 MB. It also describes unlisted review links that do not require a repository, branch, or pull request. These are vendor-described capabilities; verify the current service and policy before relying on them.

1. Create a patch with git diff or obtain the patch URL from your code host.
2. Check the file size and remove credentials or private data.
3. Paste the text, upload the file, or provide the raw URL.
4. Choose unified or split layout if the viewer offers both.
5. Use file navigation to inspect high-risk paths first.
6. Copy a share link only after confirming who can access it and how long it is retained.

Do not describe a third-party viewer as private unless its current terms say so. The research available for this article does not establish SharePatch retention or confidentiality guarantees.

Inspect a pull-request diff from the command line

GitHub CLI provides a convenient local path for pull requests:

gh pr diff 123 --repo owner/project

To request patch format:

gh pr diff 123 --patch --repo owner/project

The CLI documentation also describes an option for opening the pull request in a browser. Use the browser view when you need line comments and review submission; use the terminal output for scripts, quick checks, or offline work.

Review diffs in VS Code or Gerrit

VS Code can inspect repository changes and GitHub reviews inside the editor. This is useful when you want to jump from a changed line to local definitions, tests, or call sites. Keep the same review discipline: identify the comparison base, hide whitespace only while scanning, and return to the raw view before approving.

Gerrit’s documented interface provides a side-by-side view for a patch and supports comparison between patch sets against a selected base. It fits teams that need iterative patch-set review rather than a single pull-request page.

A practical visual code-review checklist

1. Confirm scope: check the base branch, source commit, target commit, and expected files.
2. Scan the file list: look for unexpected generated files, lockfile churn, renames, and deleted tests.
3. Read the change in context: expand surrounding lines and inspect callers, error handling, and data validation.
4. Review behavior paths: trace success, failure, empty, timeout, permission, and retry cases.
5. Check tests and configuration: verify that tests, migrations, feature flags, and deployment files match the code change.
6. Separate formatting from logic: hide whitespace to find logic, then turn it back on to ensure formatting did not alter strings or indentation-sensitive code.
7. Leave actionable comments: identify the risk, location, and a concrete next step.
8. Record the decision: approve only after checks and unresolved conversations are clear.

Edge cases that make diffs confusing

Whitespace-only changes

Large formatter runs can bury a one-line logic change. Use whitespace hiding for triage, then inspect the full diff before merging. A word-level diff can help with prose or long strings, but Git’s documentation notes that word-diff output can be larger than a dedicated word-diff tool.

Renames and moved code

A rename may appear as a delete and an add when similarity is low. Review both sides and verify that permissions, history, imports, and tests were preserved.

Binary files and generated assets

Many viewers cannot render binary changes as meaningful lines. Check the build or asset manifest and inspect generated output through the tool that owns that format.

Submodules and nested repositories

A parent diff may show only a commit pointer. Open the nested repository and compare the referenced commits there.

Large patches

Browser viewers may paginate, truncate, or become slow with very large files. Filter by directory, review commits separately, or generate focused diffs such as git diff main...feature -- src/ tests/.

Merge commits

A merge commit can have multiple parents and an unexpected combined diff. Compare each parent explicitly when the pull request result is difficult to explain.

Common errors and fixes

Problem	Likely cause	Fix
“No changes” appears	Wrong branch, identical commits, or a different merge base	Run git log --oneline and compare explicit commit IDs; confirm the pull request base.
Patch will not parse	HTML page pasted instead of raw patch, truncated upload, or malformed headers	Download the raw .diff/.patch URL and validate locally with git apply --check file.patch.
Only one side is visible	Unified layout or a collapsed hunk	Switch to split view and expand context around the hunk.
Thousands of unrelated lines changed	Line-ending conversion, formatter run, or generated files	Check .gitattributes, hide whitespace, and filter generated paths.
Comments cannot be added	The page is a standalone rendering or your account lacks repository permission	Open the pull request in its host platform and verify review permissions.
Private code is exposed	A patch was uploaded to an external viewer or shared link	Revoke the link if possible, remove sensitive data, and review the provider’s current retention policy.

Performance, reliability, and cost considerations

Local Git and editor workflows avoid upload time and third-party retention, so they are the safest choice for confidential code and very large patches. Hosted pull-request views add collaboration context but depend on repository permissions and the code host’s availability. Standalone viewers reduce setup for one-off files but add an upload, size limit, and policy decision.

For repeatable visual records of a public review page, automate a browser capture only after the page has loaded and the relevant diff is expanded. Cache stable captures when you do not need a fresh render. Keep raw patches as the source of truth; a screenshot cannot be searched, applied, or reviewed line by line as reliably as the patch itself.

Or skip the browser setup

If your goal is a clean image of a diff page, documentation page, or review result rather than an interactive review, ScreenshotNeo returns a screenshot or PDF from one GET request. It accepts the URL and supports PNG, JPEG, WebP, and PDF output through its capture options. See the ScreenshotNeo documentation for the complete parameter list.

Cookie banners, newsletter popups, and chat widgets are removed before the shot. Bot checks, blank pages, failed loads, timeouts, and cache hits are not billed, and the response identifies the page verdict and billing result with X-Page-Verdict and X-Billed headers. An MCP server provides take_screenshot, get_page_info, and capture_pdf tools for Claude, Cursor, and other MCP clients. The free plan includes 1,000 screenshots each month with no card; paid plans start at $5 for 3,000 shots.

cURL

curl -G "https://api.screenshotneo.com/v1/shot" -d access_key=YOUR_API_KEY --data-urlencode url=https://github.com/owner/project/pull/123/files -o review.webp

Python

import requests

r = requests.get(
    "https://api.screenshotneo.com/v1/shot",
    params={
        "access_key": "YOUR_API_KEY",
        "url": "https://github.com/owner/project/pull/123/files",
    },
    timeout=90,
)
r.raise_for_status()
open("review.webp", "wb").write(r.content)

Node.js

const q = new URLSearchParams({
  access_key: 'YOUR_API_KEY',
  url: 'https://github.com/owner/project/pull/123/files'
});
const res = await fetch(`https://api.screenshotneo.com/v1/shot?${q}`);
if (!res.ok) throw new Error(`Screenshot failed: ${res.status}`);
const data = Buffer.from(await res.arrayBuffer());
await import('node:fs/promises').then(fs => fs.writeFile('review.webp', data));

For long Files changed pages, use full-page capture and a wait condition or delay so the diff has rendered. You can also capture one element by CSS selector, apply custom CSS, choose a device preset or viewport, set a retina scale, block unnecessary requests, provide cookies or headers, and cache a URL with a TTL you choose. Async jobs, signed webhooks, bulk capture for up to 100 URLs per call, signed links, usage data, and PDF page controls are available when your workflow needs them.

Create a free ScreenshotNeo account with 1,000 screenshots a month and no card.

FAQ

How can I view a Git diff online without a pull request?

Generate a unified patch with git diff, then paste or upload it to a standalone viewer that supports .diff or .patch. Remove secrets first and check the provider’s current privacy terms.

Which view is better, unified or split?

Use split view when both versions fit on screen and you need direct line-to-line comparison. Use unified view for narrow screens, long files, or faster scanning.

Why does GitHub show a different file list than my local diff?

The commands may use different bases. GitHub documents that compare and pull-request pages can calculate changed files from different merge bases. Compare the exact commits and merge base locally.

Can an online viewer apply a patch?

A visual viewer normally renders changes. To validate or apply a patch, use Git locally, for example git apply --check file.patch followed by git apply file.patch after reviewing it.

Should I upload a private repository’s patch?

Only after reviewing the service’s access, retention, and deletion terms. A patch can contain both current and removed secrets, so local tools are preferable for sensitive material.