Diffchecker vs Difftastic

Diffchecker compares text, code, and data in a browser or offline with its desktop app, highlighting additions, removals, and edits. Text comparisons can use side-by-side or unified views, adjustable precision, custom ignore rules, syntax highlighting, real-time editing, and change merging. Listed comparison options also include documents, images, spreadsheets, and folders, with features such as OCR, redlines, formula detection, and batch comparison. Basic is free, but some tools have monthly use limits: unified view and real-time editing each allow five tries, while character-level differences and merge changes each allow ten. Pro + Desktop costs $15 a month per user and includes offline comparisons with desktop apps for Windows, Mac, and Linux. Legal costs $20 a month per user and adds iManage integration and comparison-setting profiles. Enterprise costs $40 a month per user with annual billing, and includes SAML SSO, SCIM provisioning, and dedicated support. Browser comparisons stay in the browser unless saved and shared; Desktop comparisons run locally. The site states browser traffic is TLS-encrypted and its security program is ISO/IEC 27001 certified.

Difftastic is a command-line diff tool that compares files by syntax rather than matching lines alone. It identifies a file’s language, parses its code, and compares syntax trees with tree-sitter. The manual lists support for more than 30 programming languages, and the site names HCL, HTML, JSON, and YAML among supported formats. It can identify expressions that remain unchanged through whitespace or line-wrapping changes and show the files’ actual line numbers. Unsupported formats and extremely large inputs instead receive a conventional line-based diff with word highlighting. Difftastic can be configured as Git’s external diff command and used with Git subcommands; the manual also links configuration instructions for Mercurial, Fossil, and Jujutsu. Folder comparison and syntax highlighting are supported, while merge scope is two-way. Prebuilt binaries are available for Linux, macOS, and Windows, and the manual lists package-manager installation options. Difftastic is free, open source, and MIT licensed. The manual warns that Git 2.43.1 and earlier can crash when an external diff is used if file permissions have changed.