Sup
Sup: A focused open-source client for indexed, tag-based email on Linux and macOS. Ranked #129 of 142 in Email Clients by our editors (3.0/10); pricing: Open source; best for technical users wanting indexed, tag-based email.
At a glance
- Editor score3.0 / 10
- PricingOpen source
- Best forTechnical users wanting indexed, tag-based email
- Paid fromFree
- App coverageDesktop
- Facts checked20 Sep 2026
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
Our verdict on Sup
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.
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Sup pricing
Sup fact sheet
| Free plan | Not verified |
|---|---|
| Paid from | Free |
| App coverage | Desktop |
| Account limit | Not verified |
| Unified inbox | Not verified |
| Offline access | Not verified |
| Scheduled sending | Not verified |
| Calendar tools | Not verified |
| Deployment | Self-hosted, Desktop |
| Platforms | Linux, macOS |
| Support | Community, Docs |
| Built for | Solo, Small business (editorial estimate) |
| Pricing | Open source |
| Website | supmua.dev |
| Facts checked | 20 Sep 2026 |
Alternatives to Sup
- Mozilla ThunderbirdA capable free client for multi-account email, offline access, and desktop productivity tools.9.4
- Zoho MailA flexible hosted email service with free access, migration tools, and Zoho collaboration options.9.2
- Apple MailA capable Apple-focused email client with unified inboxes, scheduling, privacy controls, and AI assistance.9.1
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Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
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