Sup review
A focused open-source client for indexed, tag-based email on Linux and macOS.
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
Sup is an open-source, console-based email client for technical users managing large email collections. It organizes messages into tagged threads, indexes email locally for full-text search, and supports query-language searches across mail. Multiple email accounts, mbox and Maildir sources, and automatic recent-contact tracking make it suited to users with established local mail workflows. Sup is designed for Unix-like environments, with Linux and macOS support, and is maintained by the Sup community.
Its strongest differentiator is the depth of its local email organization. Thread-based views and tags provide a structured way to manage messages, while local indexing supports full-text retrieval without relying on a remote search system. Multiple accounts and support for both mbox and Maildir sources broaden its fit for users consolidating existing mail. GPG support adds an additional security-oriented capability, and Ruby-programmable hooks give technical users a way to customize behavior around their own workflows.
Sup is distributed as open-source software and can be installed locally through RubyGems or the source repository. Its desktop coverage is centered on Linux and macOS, and its console-based design keeps the product focused on email management rather than broader productivity features. Users who value searchable local archives, tags, scripting, and control over mail sources should consider Sup. Those who want a graphical interface, broader platform coverage, scheduling, or calendar functionality should choose a different email client.
Sup pros and cons
- Where it wins
- Local full-text indexing and query-language search
- Thread organization with tags and multiple-account support
- Ruby hooks and GPG support for customization and security
- Where it doesn't
- Console-based interface may not suit graphical-email users
- Platform coverage is limited to Linux and macOS
- Focused on email rather than scheduling or calendar work
Sup fact sheet, pricing and score →
Advertiser disclosure: iTechGuides is reader-supported. Vendors can pay for top positions in our rankings and for a place on other products' pages, and we may earn a commission when you click some links. Bought places stand at the number bought; this page and our disclosure say so. Paying vendors may get a fuller, more detailed review from our editors, and that review can change their score. How we rank.
Last updated · How we research and update