# Build brief — a focused alternative to Mailient > **Verdict:** Partly, if you narrow it · **Buildability:** 56/100 · **Category:** Email > **Source:** https://www.canitbevibecoded.com/mailient > Independent editorial assessment from Can It Be Vibe Coded? Not affiliated with, endorsed by, or derived from Mailient. Verify current pricing and capabilities before acting. ## Context **Mailient** — An AI layer over your inbox that sorts, summarizes and drafts replies to email. It currently costs $29/mo. The core trick here, pull mail, classify it, summarize threads, draft replies, is genuinely a focused implementation of work now that an LLM does the hard part. An agent can wire IMAP plus SQLite plus a cheap web UI and have working triage before dinner. The gaps are all the unglamorous parts: Gmail and Outlook OAuth, push sync instead of polling, threading edge cases, and the fact that you will read this thing on a phone and your build has no app. Nothing here is protected by data or network, so a personal version keeps most of the value if you accept that you are now the ops team for your own mail pipeline. Product details and pricing are thin from the outside, so treat the specifics as unverified. This brief describes a focused, single-operator replacement for the part of Mailient that is genuinely reproducible. It is deliberately narrower than the product it replaces, and it says so in writing. Build the useful core; do not pretend to have rebuilt the rest. ## What you are building Polls your IMAP inbox, classifies and summarizes each thread with an LLM, and parks suggested replies in a local review queue you approve before sending. - Read, draft, and triage mail through provider APIs with explicit rules you control. - A responsive interface with real empty, loading, success, and error states. ## Requirements ### Functional - A machine or small VPS that stays awake to poll. - Basic comfort debugging MIME, threading and character encodings. ### Data and integrations - An email account with IMAP/SMTP access and an app password, or patience for OAuth. - An LLM API key, and acceptance that your mail text goes to that provider. Each of these needs a real account, credential, or quota. Set them up before writing feature code. ### Non-functional - Accessibility: semantic markup, labelled controls, visible focus, and reduced-motion support. - Security: server-side secrets, validated input, and no credentials in the client bundle. - Reliability: retries with backoff on external calls, and a clear failure state when a provider is down. - Portability: the operator can export their data and leave without losing it. ## Implementation brief Build a local AI email triage tool called Inbox Warden in this empty folder. Stack, no substitutions: TypeScript on Node 20, Fastify for the server, server-rendered HTML with htmx for the UI, better-sqlite3 for storage, imapflow for reading mail, nodemailer for sending, and one OpenAI-compatible chat completions endpoint for the AI. No React, no Next, no Docker, no cloud services, no telemetry, no user accounts. This runs on localhost for exactly one person. Secrets in .env, read with a tiny loader, and ship a .env.example with: IMAP_HOST, IMAP_PORT, IMAP_USER, IMAP_PASS, SMTP_HOST, SMTP_PORT, LLM_BASE_URL, LLM_API_KEY, LLM_MODEL. Never log credentials or full message bodies. What is in scope: - A sync job that connects over IMAP, fetches messages from INBOX since a stored high water mark, and stores id, thread key, from, to, subject, date, plain text body and raw headers in SQLite. Dedupe on Message-ID. Make sync idempotent and resumable. - Strip HTML to text and truncate long bodies before sending anything to the model. - For each new thread: one LLM call returning strict JSON with category (one of urgent, needs-reply, fyi, newsletter, junk), a two sentence summary, and a suggested reply draft when category is needs-reply or urgent. Validate the JSON with zod and retry once on parse failure. - Cache results keyed by thread and message count so restarts do not re-bill you. - A web UI at / with a triage queue grouped by category, thread detail view, and an editable draft box with Approve and Send, Skip, and Mark Junk. Nothing is ever sent without an explicit click. - Sending via SMTP with correct In-Reply-To and References headers so replies thread properly. - A rules table for cheap deterministic overrides by sender or subject substring, applied before any LLM call. - npm run sync, npm run dev, and a --dry-run flag that classifies without sending. Explicitly out of scope: OAuth flows, mobile app, push notifications, multi-account support, calendar, attachments beyond recording filenames, search beyond a SQL LIKE query. Write a README with setup steps, an honest limitations section that says polling is not push and that message text leaves the machine for the model, and a cost note estimating tokens per hundred emails. Include a fixture-based test for the classifier JSON parser that does not hit the network. ## Delivery standard - Inspect the repository first, then write a short implementation plan before writing code. - Deliver the smallest complete end-to-end workflow first; every primary control must work against persisted data. - Use real validation and storage; never substitute fake dashboards, decorative controls, hard-coded success states, or mock integrations. - Include responsive layouts plus genuine empty, loading, success, validation, and failure states. - Keep secrets server-side in environment variables, provide .env.example, and never commit credentials or user data. - Add structured logs around every external call and return actionable errors without leaking sensitive details. - Write unit tests for the core logic and one automated test of the main user journey. - Finish with a README covering setup, architecture, data location, backups, tests, deployment, and known limitations. ## Acceptance criteria - [ ] A clean install starts the app using only the README and .env.example. - [ ] The primary journey works from first visit through saved result, reload, edit, export, and deletion where applicable. - [ ] Invalid input, missing configuration, provider failure, and an empty database each have a usable state. - [ ] The interface works at 390px and 1440px, is keyboard navigable, and shows visible focus on every control. - [ ] Tests, type checking, linting, and a production build all pass with no ignored failures. - [ ] No part of the interface implies a live integration, security guarantee, or scale capability that was not actually built and verified. ## Non-goals Do not build these, and do not claim to have replaced them: - A mobile app and real push notifications, which is where most email actually gets read. - Managed OAuth with Google and Microsoft, including the review process and token refresh pain. - Someone else absorbing provider API changes, rate limits and broken threading. - Polish: keyboard shortcuts, fast search, snooze, undo send, offline behavior. - Any sending reputation work if the product handles outbound at scale. ## What you still own after launch - Secure credentials, rotate secrets, and handle provider rate limits. - Run migrations, backups, restores, and dependency updates. - Test the critical journey after every model, API, or hosting change. - Monitor failures and fix the edge cases a first prompt will miss. - Maintain every third-party integration as APIs and OAuth rules change. ## Risk **Operational risk.** The code is achievable; dependable data, integrations, and ongoing operations are the real cost. Editorial confidence in this assessment: low. No reviewed project implementation is linked yet. --- Generated by [Can It Be Vibe Coded?](https://www.canitbevibecoded.com) · Full report: https://www.canitbevibecoded.com/mailient