Kaito Mail
An AI-assisted unified inbox (Gmail, IMAP, or a self-hosted domain) built on a genuine from-scratch AWS mail pipeline, with an email-derived personal-finance and life-admin layer on the same rails.
- From-scratch pipeline
- own MIME, threading, spam and AV
- 3 ways to connect
- Gmail, IMAP, or a hosted domain
- Life-admin built in
- finance, calendar, packages, deadlines
The problem
Email is where most of life's admin actually happens — receipts, bills, bookings, deliveries, deadlines — but a normal inbox does nothing with any of it. Kaito Mail is a unified, AI-assisted inbox that also reads the useful structure out of your mail: your spending, your calendar, your packages, your deadlines.
What it does
You connect email through Gmail, generic IMAP/SMTP, or a domain hosted on Kaito itself, and it reshapes email into a Slack-style chat surface — live updates, shared and claimable mailboxes, mentions, snooze. Incoming mail for a Kaito-hosted domain flows through a genuinely from-scratch pipeline built on AWS's mail services that parses, spam- and virus-checks, threads, and files each message.
On top of that runs a large life-admin layer most inboxes don't have: it parses bank statements and receipts from your mail (and uploaded documents) and classifies the transactions with a language model, tracks budgets and subscriptions, ingests calendar invites, tracks package deliveries, and extracts deadlines — all riding the same mail pipeline. Remote images are blocked by default for privacy, and the sensitive parts of a message are encrypted at rest.
Key features
One inbox across your accounts
Gmail, IMAP, or a Kaito-hosted domain all land in one AI-assisted inbox, so you're not tab-switching between mail accounts.
Email as a chat surface
Mail is reshaped into a Slack-style surface with shared mailboxes, mentions and snooze, so a small team can actually work an inbox together instead of forwarding threads around.
Your spending, read out of your mail
It parses receipts and statements and classifies the transactions, tracking budgets and subscriptions — so the financial life already sitting in your inbox becomes something you can see.
Calendar, packages and deadlines too
Invites, delivery tracking and deadlines are extracted from mail automatically, so the admin buried in your inbox surfaces instead of getting lost.
Private by default
Remote tracking images are blocked out of the box and the sensitive parts of a message are encrypted at rest, so reading your mail doesn't quietly report back to senders.
Where it stands
Live and self-hosted, so there's no public link to it yet. Encryption at rest covers previews, headers and the archived raw message, not the rendered display body.
Under the hood — for the technically-minded
How it's built
Kaito Mail is a React Router 7 app over a large Postgres schema, with sending routed per account to the right transport — Gmail, IMAP/SMTP, or SES. The headline engineering is the inbound pipeline for Kaito-hosted domains, built from scratch on AWS's mail stack (receipt rules to storage to a queue) and consumed by a worker that does its own MIME parsing, threading, layered spam and virus checks, and encryption — not an off-the-shelf mail server.
The spam pipeline is a good example of the care taken: a provider verdict, then an open-source scanner, then hand-built phishing heuristics, and only for genuinely uncertain cases a language-model second opinion — cost-controlled by construction. A large finance/calendar/shipments/deadlines subsystem rides the same pipeline, accounting for much of the schema and routes.
The hard problems
Building a real mail pipeline, not wrapping one
Inbound and outbound are built from scratch — its own MIME builder, its own threading logic, a multi-transport outbound router, and a layered spam/virus pipeline — rather than leaning on a packaged mail server. That's the genuinely hard, and genuinely impressive, core of the project.
Turning an inbox into life-admin, carefully
Parsing money, calendar events, packages and deadlines out of messy real-world email is hard and error-prone, so extraction is structured, classified with a model only where needed, and cost-controlled with cheaper checks first — a deliberate pipeline, not a single AI call over everything.
Honest about what's encrypted and what ran
A candid internal audit found and fixed real issues (including a login-MFA bypass and a stored-content injection) in one pass. And the encryption story is stated precisely: previews, headers and the archived raw message are encrypted at rest, while the rendered body used for display is stored in plaintext — not rounded up to 'your email is encrypted.'
Built with
- React Router 7
- Drizzle
- Postgres
- AWS SES/SQS/S3
- Anthropic Claude
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