Does Letterbot require ChatGPT or any paid AI?
No. Letterbot works fully in deterministic mode without any external AI. GigaChat (free, by Sber) and Cloudflare Workers AI (free tier) are optional enhancements you enable explicitly. OpenAI is supported but not required.
Where do my emails go?
Nowhere external. Letterbot reads email via IMAP directly from your mail server. Processing is local. SQLite database is on your machine. There are no Letterbot servers — they do not exist.
Is Letterbot really free forever?
Yes. AGPL-3.0 open source. No freemium, no Pro tier, no subscription. Development is sustained by voluntary donations via Boosty and CloudTips.
How many email accounts can I connect?
Unlimited. Add as many IMAP accounts as you need. Each can be routed to a different Telegram chat. There is no account limit.
Does it work on an old or slow computer?
Yes — tested on Intel Celeron N4020 with 3 GB RAM. Uses 40–120 MB RAM. Old laptops make excellent dedicated email assistants.
Can Letterbot reply to emails?
No. Letterbot is read-only — it reads, analyzes, and notifies. It never modifies, deletes, or sends email. This is by design: notification and response are separate concerns.
What email providers are supported?
Any provider with IMAP access: Gmail, Yandex, Mail.ru, Outlook/Microsoft 365, custom domains, self-hosted mail. IMAP is the only protocol used.
Does it work without internet?
The deterministic core works offline. IMAP polling requires network access to your mail server. LLM features (optional) require internet. If AI is unavailable, Letterbot continues in degraded mode.
What happens if the LLM is unavailable?
Letterbot switches to DEGRADED_NO_LLM mode automatically. Basic priority and notifications keep working using deterministic rules. You are notified about the degradation.
How does priority classification work?
A deterministic rules engine extracts facts from subject, body, and attachments, then scores priority based on mail type, amounts, deadlines, sender history, and 20+ signal types. Each decision has auditable reason codes.
Does Letterbot read attachments?
Yes. PDF (via pypdf), Excel (openpyxl/xlrd), and Word (python-docx) are extracted locally without Office installed. Invoice amounts and due dates are detected automatically.
What is the weekly digest?
A Monday morning Telegram summary: invoices, contracts, overdue commitments, stalled conversations, and your priority correction accuracy trend.
How does snooze work?
Tap snooze in Telegram → email returns later with full context: who sent it, what was needed, how many times you snoozed it. Context is restored from the event store.
What is the web cockpit?
A local read-only dashboard at localhost:8787. Shows system health, processed emails, AI decision traces, delivery metrics. Never exposed to the internet.
Can I use Letterbot on Linux or macOS?
Letterbot is optimized for Windows. Running from source on Linux/macOS may work but is not officially supported or tested.
How does Letterbot learn from my corrections?
When you change a priority in Telegram, the correction is recorded per sender+account pair. After 3+ corrections with ≥80% accuracy, Letterbot adapts future priorities with a bounded ±12 bias over a 45-day window.
Is the source code really open?
Yes. Full source at github.com/SergioTheFirst/letterbot under AGPL-3.0. 74,000 lines of Python, 1,541 tests, CI on GitHub Actions.
What languages are supported?
English and Russian. Switch with /lang en or /lang ru in Telegram. All notifications, digests, and commands are localized. Quality is verified by a 120-case bilingual golden corpus.
Does it work with Exchange or Microsoft Graph?
No. Letterbot uses IMAP only. Exchange Web Services and Microsoft Graph are not supported. Most Microsoft 365 accounts support IMAP alongside Exchange.
How do I update Letterbot?
Download the latest ZIP from GitHub Releases, replace the executable, keep your config files and database. Your settings and learning history are preserved.
What is the Trust Score?
A reliability profile for each contact. Tracks whether they meet deadlines, respond on time, and keep commitments. Trust decays over time and recovers — no permanent penalties.
What are commitment tracking and silence detection?
Letterbot detects phrases like 'will send by Friday' and tracks them. It also notices when regular contacts go silent unexpectedly — both surface in the weekly digest.
How secure is the IMAP connection?
Letterbot uses SSL/TLS (port 993) by default. Credentials are stored locally in your accounts.ini file. No credentials are transmitted to any Letterbot server.
What data is stored locally?
Email metadata only: sender, subject, date, priority score, and analytics. Full email text and attachments are NOT stored. The SQLite database is next to the executable.
Can multiple people use the same Letterbot instance?
Yes. Each email account can route to a different Telegram chat or group. One Letterbot instance can serve a small team.