Three approaches cover almost every need for comparing files in a GitHub project. Use the GitHub Compare view or git diff for most tasks, and pick a third-party visual diff or folder-compare tool when the web UI can't show two arbitrary file paths side by side. The built-in Compare view is what you get when you open a new pull request and is best for branch-to-branch, branch-to-tag, or commit-level reviews, while git diff gives absolute flexibility for file-level, ref-qualified comparisons. If you need a prettier online render for differently named files, fetch raw blobs and paste them into a trusted visual diff service such as diffchecker.com or use a URL-importing tool like mergely.com.
Here’s the answer up front: if you want a quick browser link to share with teammates, use GitHub’s Compare view. If you need a flexible, scriptable comparison of arbitrary paths or commits, run git diff. If the files have different names and you want a polished side-by-side HTML output, use a third-party visual diff that can import raw files.
When the GitHub web UI is the right tool
You get to the Compare view by appending /compare to any repository URL. The page shows two drop-downs labeled base and compare. GitHub Docs spells out the meaning: base is the starting point and compare is the endpoint. You can swap them by clicking Edit. Practically, that's the very same UI you land on when you open a New Pull Request, so the web view is optimised for review workflows and preparing merges.
The web UI covers the common team scenarios. GitHub Docs gives examples for comparing branches and comparing tags. A useful detail in those docs is the behaviour when a branch and a tag share a name. In that case, the branch is used unless you explicitly prefix the tag with tags/. The Compare view also supports cross-repository or cross-fork comparisons by prefixing branch names with owner names, for example owner:branch. That syntax is handy when you want to show differences between an upstream repository and a fork without checking anything out locally.
You can even compare individual commits in the browser. GitHub Docs documents a two-dot commit comparison URL pattern, for example compare/shortSHA..shortSHA, which renders the diff between two commits. That makes it simple to produce an online view of commit-level changes for reviewers who prefer a browser link over a local git session.
When to use git diff instead
The command line remains the most flexible option. For ad hoc, ref-qualified, or scripted comparisons you will rely on git diff.
DelftStack documents the standard invocations you will use locally: git diff <commit1> <commit2> to compare commits, git diff <branch1> <branch2> to compare branches, and git diff <path-to-file1> <path-to-file2> to compare two files.
Frankly, to compare versions of files that live on different refs, include the ref qualifier. For example, DelftStack shows git diff HEAD:docs/tutorial/01.c HEAD:docs/tutorial/02.c to compare two files that have different names or reside in different branches. Use git diff when you need to script comparisons in CI, when files are large, or when the files you want to compare aren't both addressable by the web UI.
GeeksforGeeks points out what many teams already know: the GitHub branch comparison tool shows commits, changed files, and line-by-line differences, and the pull request flow layers on inline review and commenting tools. But if you want absolute control over which blobs you compare, or if you need to pipe the output into other tools, git diff is the non-optional choice.
What the web UI can't do, and the practical alternatives
The GitHub web UI is limited when your use case is "compare two arbitrary file paths with different names in the repository via a live online diff." A StackOverflow thread documents a user attempting to force the /compare URL to diff two differently named files and concluding that approach doesn't work. The thread suggests third-party diff services that can import files from URLs as an alternative. Note that some of those tools don't automatically follow HEAD unless you configure them to fetch the latest blobs.
Two examples mentioned in that thread are diffchecker.com for a quick online view and mergely.com for URL import. Both can produce a readable side-by-side rendering if you fetch the raw files first. The practical workflow is simple: open the raw file URLs from GitHub, paste the contents into the visual diff tool, or point the tool at the raw URL if it supports URL import. Confirm that the tool pulls the repository revision you want, because not all services default to the live HEAD blob.
For large folder or remote comparisons where files aren't co-located, GitHub’s Topics page for file-comparison points to command-line utilities that compute CRC stamps or otherwise compare whole directory trees. Those tools are useful when you need a scalable, noninteractive comparison of folder hierarchies and when performance matters more than an interactive HTML view.
Choosing the right option for your workflow
Make the decision with one question: do you need a shareable browser diff or absolute flexibility? If you need a link to share with reviewers, or you are preparing a merge, use the GitHub Compare view or open a New Pull Request. If you need to compare two commits or two branches locally, run git diff <commit1> <commit2> or git diff <branch1> <branch2> as DelftStack documents. And if the two files have different names or live on different refs, use the ref-qualified form such as git diff HEAD:docs/tutorial/01.c HEAD:docs/tutorial/02.c.
If the visual presentation is important and the files can't be compared in the web UI, fetch the raw blobs and paste them into a trusted visual diff site such as diffchecker.com, or use a URL-importing service like mergely.com after confirming it pulls the repository revision you want. For large-scale folder comparisons, follow the guidance linked from GitHub’s Topics page for file-comparison and pick a command-line tree-compare utility.
I'll save you the trouble of chasing edge cases. The web Compare view and the pull request UI cover the vast majority of team workflows and give you inline comments and review context. Use git diff when you need precision, scripting, or to compare arbitrary file paths. Use a visual diff service when the GitHub UI can't show the two files side by side and you need a cleaner presentation.
Treat the examples as copy-paste recipes. Open https://github.com/your-user/your-repo/compare to try the web flow. Run git diff <commit1> <commit2> locally for quick checks. And if you must compare differently named files in a browser, fetch the raw URLs and try diffchecker.com or mergely.com, confirming the revision first.
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Start with the Compare view or a New Pull Request for most team reviews. If you need scripting or to compare arbitrary refs, run git diff HEAD:docs/tutorial/01.c HEAD:docs/tutorial/02.c locally; if the files have different names and you want a cleaner side-by-side render, fetch the raw blobs and paste them into a trusted visual diff such as diffchecker.com or use mergely.com after confirming it pulls the correct revision.
This article was created with AI assistance.
