Show HN: Mocca – A Mac email client powered by local AI

Mocca, a new Mac email client, uses a local on-device AI to classify mail, curate inboxes, and execute plain-English rules without sending data to the cloud. The app connects to existing inboxes via IMAP, supporting Gmail, iCloud, Yahoo, and Fastmail, and allows users to define labels and actions in natural language.

Mocca is a desktop email client that connects to your existing inbox and runs an LLM on your machine to classify mail, curate the inbox, and apply rules you write in plain English. No email or content leaves your computer. No filters, no regex, no conditions to wire up. You describe what you want in plain English — an AI on your Mac reads every email and carries it out. Define your Inbox in one sentence. The AI reads every incoming email and keeps your Inbox to exactly that — everything else is sorted into All Mail, not lost. It judges the content, not a list of sender filters you have to maintain. Define a label by what it means, in your own words — Mocca reads the content and applies it to any matching email, whoever sent it. Add an action and it does that too: trash, unsubscribe, mark read, mute. “What did I buy from Amazon last month?” It reads the real emails and answers. Or tell it several things at once — “trash promotions and unsubscribe from newsletters” — and approve them together. Connect your email, and Mocca sorts the rest — locally. Sign in with an app password over IMAP. Guided setup for Gmail, iCloud, Yahoo and Fastmail. The on-device AI reads your latest mail, separates the important from the noise, and applies your labels and rules. Write rules in plain words, let Mocca auto-handle the junk, and ask questions across your whole inbox. Straight answers — including the limits. A private inbox with a built-in AI. Connect your email and you're set — no cloud, no account.