Email List Hygiene & Inactive Cleaner
Import your subscriber list, automatically flag hard bounces, role and spam-trap-looking addresses, duplicates, and long-inactive contacts, then approve a clean suppression batch that protects your sender reputation - no contact removed without a human OK.
A private, login-protected tool that ingests your list, applies your own hygiene rules, proposes a suppression batch with reasons and counts, waits for a manager's approval, and exports a clean list plus a suppression CSV in your ESP's column format.
Before you start
- A subscriber export (CSV) with email, status, signup date, last-open / last-click dates, and bounce flags
- Free Vercel, Supabase, and Resend accounts (the plan walks you through them)
- Claude Code installed and a quiet afternoon or weekend
The problem this kills
Your open rates are sliding and you can feel the list rotting. Hard bounces keep coming back. Half-dead contacts who haven't opened anything in a year are quietly dragging your sender reputation down, so even your good emails land in spam. You know you should clean the list, but doing it by hand in a spreadsheet is terrifying - one wrong filter and you delete paying customers or trip an automated unsubscribe you can't undo.
So nothing gets cleaned, and it gets worse every send.
This tool turns list hygiene into a calm, reviewable routine. It does the tedious flagging for you - bounces, role addresses, spam-trap-looking patterns, duplicates, long-inactive contacts - and then it stops and waits for a human to say "yes, suppress these." Nothing is ever removed automatically.
What you'll build
A small private web app, just for your team, that:
- Imports your subscriber CSV (or connects to your data later) and lands every contact in a secure database.
- Applies hygiene rules tuned to YOUR list: your inactivity threshold, your definition of a "role address," your re-engagement carve-outs.
- Flags hard bounces, role/spam-trap-looking addresses, duplicates (matched on the lowercased email), and long-inactive contacts - each with a plain-English reason.
- Merges duplicates intelligently, keeping the most engaged record.
- Builds a proposed suppression batch with counts and reasons, grouped so you can review at a glance.
- Waits for a manager to approve before anything is marked suppressed - the hard human gate.
- Exports a clean list and a suppression list as CSVs in the exact columns your email platform expects.
What's inside the Implementation Plan
The plan is a single file you paste into Claude Code. The first thing it does is interview you about your business - your current cleanup process, which email platform and columns you use, how your dates and bounce flags are named, your typical and peak list sizes, your real inactivity and role-address rules, and the messy edge cases (re-engagement campaigns, B2B role inboxes you actually want to keep, re-subscribed contacts). It reflects a short tailored spec back to you and gets your thumbs-up before building anything. That means the tool fits your list, not a generic template.
From there it builds step by step, each step ending with a ready-to-paste prompt: the database and login, the import, the hygiene rules, the review-and-approve screen, the audit trail, and the CSV exports.
The governance it includes (this is the point)
- Login so only your team can open the tool.
- Row-level security so each organization only ever sees its own contacts.
- A complete audit trail - who imported what, who approved which batch, and exactly when.
- A hard human-in-the-loop approval gate - the AI drafts the suppression batch; a person reviews reasons and counts and approves; only then is anything marked suppressed.
- Duplicate guards so the same import or the same contact can't be processed twice.
Who it's for
Email and marketing operations people who manage a newsletter or customer list, watch their open rates with a knot in their stomach, and want a safe, repeatable way to keep the list healthy - without writing code and without risking an accidental mass delete.
You've got this. Paste the first prompt and let the interview tailor the tool to your list.