Skim
Free, open-source native Windows email client with local offline storage and optional AI using your own key.
About Skim
Skim is a free, open-source native Windows email client with a Rust core and system WebView2 interface. It starts quickly from cold, requires no administrator privileges, and stores email in a local SQLite database synced through IMAP. Search is instant, offline actions are queued and sent automatically when connectivity returns, and one shortcut can search email, jump to folders, run commands, or ask AI about the entire mailbox. AI features require your own Anthropic or OpenRouter key and also support OpenAI-compatible APIs and local models such as Ollama; requests go directly to providers with no markup. Gmail, Outlook, iCloud, and other IMAP/SMTP mailboxes are supported.
Best for
Best use cases
Process and search email offline, then automatically sync queued actions when connectivity returns
Use one shortcut to search email, switch folders, and run quick commands
Ask AI questions and find email content across the entire mailbox
Connect local models through Ollama, LM Studio, or vLLM to power AI features
Features
Local-first email synchronization
Email is synchronized via IMAP to a local SQLite database, works offline, returns search results instantly, and queues offline actions for automatic sending when connectivity returns.
Keyboard-first control
One keyboard shortcut searches email, jumps to folders, runs quick commands, or asks AI about the entire mailbox—all in one window, without a mouse.
Bring-your-own-key AI
Paste an Anthropic or OpenRouter key, or connect any OpenAI-compatible API with local models such as Ollama, LM Studio, and vLLM; requests go directly from your computer to the provider with no markup.
Broad provider support
Gmail supports one-click Google sign-in or app passwords; Outlook, Yahoo, and iCloud use app passwords. Any standard IMAP/SMTP mailbox is supported, with settings for major providers filled in automatically.
Pros
- Free and open source (MIT License), with no subscription, account, or upsells
- Native and lightweight, with an installer of about 5 MB, instant cold start, and low idle memory use
- Email is stored locally in SQLite; search and actions remain available offline
- Users manage their own AI keys; requests go directly to providers and are billed at cost with no markup
Cons
- No calendar, contact management, rules, filters, or snooze features
- Requires Windows 10/11 and WebView2 to run