What stays on your machine
Everything. Letterbot is an EXE file that runs on your computer. There are no Letterbot servers. No data is collected, transmitted, or shared with Letterbot or any third party.
Local storage
- SQLite database next to the executable — stores email metadata (sender, subject, date, priority score)
- Full email text and attachments are not stored — only processed in memory
- Configuration files with your credentials — stored locally, never transmitted
- Logs — stored locally, contain no email content
What goes external (if you enable AI)
If you do not enable any LLM provider, the only external connection is IMAP FETCH to your mail server. Nothing else leaves your machine.
If you enable GigaChat or Cloudflare Workers AI, a minimal text context is sent for analysis. Not the full email, not attachments, not addresses. The LLM receives only enough text to generate a summary.
IMAP connection
Letterbot connects to your mail server in read-only mode. It never modifies, deletes, moves, or flags any email. SSL/TLS (port 993) is used by default.
Telemetry
Zero. No analytics, no crash reports, no usage tracking, no phone-home. The code is open source — verify yourself.
Open source verification
Full source code: github.com/SergioTheFirst/letterbot — AGPL-3.0 license, 74,000 lines of Python, 1,541 tests.