KDiff3 vs SourceGear DiffMerge

KDiff3 is a free, open-source desktop app for comparing and merging files and folders on Linux, macOS, and Windows. It can compare two or three text files or folders, showing differences line by line and character by character. For merge work, it can combine changes automatically and includes an editor for resolving conflicts, including three-way merges. Folder comparison and Git integration are supported. KDiff3 handles Unicode, UTF-8, and other file encodings; users can highlight or hide whitespace and comment changes, and print differences. It also supports version-control keyword and history merging, with network transparency through KIO. Its listed license is GPL-2.0-or-later. The Free plan costs nothing, and there is no free trial. Linux installation options include Discover or another AppStream store, a distribution package manager, or Flathub. The app page links to a handbook, forum, and bug-reporting page. KDE describes itself as an international community building and distributing free, open-source software since 1996.

SourceGear DiffMerge is a free desktop application for visually comparing and merging files and folders on Linux, macOS, and Windows. Its Diff feature displays changes between two files, highlights differences within lines, and supports editing. Merge compares three files and can combine changes automatically when it considers that safe. Folder Diff compares two folders side by side and classifies files as identical, equivalent, different, or present in only one folder. Rulesets and options let users adjust its appearance and behavior, and it can import files in a wide range of character encodings. A command-line interface compares files and can write differences in unified or traditional formats. The manual documents integrations with Git, Mercurial, TortoiseSVN, Microsoft TFS, and Microsoft VSS 2005. Windows Explorer integration adds context-menu actions for selected files or folders. The download page lists version 4.2 builds for Windows, MacOS 10.6+, Ubuntu 12.04+, and Fedora 17+. SourceGear support stated in February 2026 that it was no longer accepting registrations and was moving DiffMerge toward an open-source project.