Auto-Unsubscribe & Newsletter Digest

Overview

A cron job that scans Ben’s maildir for newsletter/marketing emails, auto-unsubscribes, moves them out of Inbox, and sends a weekly digest so he can re-subscribe to anything he actually wants.

Decisions

Backlog: Process full backlog (~2,400 newsletter emails). Unsubscribe from all non-allowlisted senders.
File location: Omni/Cloud/Mail/NewsletterFilter.py in omni repo
Allowlist: See below

Environment

Mail server: Self-hosted on bensima.com (143.198.118.179), NixOS mailserver module (nixos-mailserver). Dovecot + Postfix.
Sieve: ManageSieve is enabled (enableManageSieve = true). Can deploy server-side sieve rules for filtering at delivery time.
Mail config: Omni/Cloud/Mail.nix (hyperspace worktree)
Mail sync: mbsync (isync) via ~/.config/isyncrc, IMAP to bensima.com:993
Maildir: /home/ben/Mail/ben@bensima.com/ (Inbox, Junk, Sent, Trash, Archives, etc.)
Search: mu 1.12.9 (Xapian-backed)
Clients: iOS Mail app + mbsync on beryllium
Host: beryllium (local machine)
Catch-all: Already enabled for bensima.com, simatime.com, bsima.me
Stats: ~6,500 emails in Inbox (3,509 new + 3,011 cur). ~2,431 have List-Unsubscribe headers (~37% of inbox).

Architecture

Two-layer approach:

Layer 1: Server-side Sieve (delivery-time filtering)

Since ManageSieve is enabled, we can deploy sieve rules that filter at delivery time. This means newsletters get filed before they hit the Inbox — iOS Mail and mbsync both see the already-filtered state.

Sieve script capabilities:

File emails with List-Unsubscribe + Precedence: bulk into Newsletters/ folder
Skip known allowlisted senders
This handles the ongoing filtering after initial cleanup

Deploy via: sievec on server, or ManageSieve protocol client from beryllium.

Layer 2: Client-side Python script (unsubscribe + digest)

Runs on beryllium via systemd user timer.

Phase 1: Classify

For each email in Inbox/new/ and Inbox/cur/:

Parse headers with email stdlib
Classify as newsletter if ANY of:
- Has List-Unsubscribe header AND sender is not on allowlist
- Has Precedence: bulk or Precedence: list
- Has X-Mailer matching known bulk senders (Substack, Mailchimp, SendGrid, Constant Contact, etc.)
- From address matches known newsletter patterns (substack.com, email., no-reply@, newsletter@*)
Classify as transactional (skip) if:
- From matches known transactional senders (banks, utilities, order confirmations)
- Subject matches patterns: “receipt”, “order confirmation”, “password reset”, “verification”
Classify as personal (skip) if:
- From address is in contacts allowlist
- No bulk/list headers
- Reply-To matches From (not a marketing redirect)

Phase 2: Unsubscribe

For emails classified as newsletter:

Extract List-Unsubscribe header
If List-Unsubscribe-Post: List-Unsubscribe=One-Click is present:
- Send HTTP POST to the unsubscribe URL (RFC 8058 one-click)
Else if URL is mailto::
- Send an email to the unsubscribe address (via msmtp/sendmail)
Else if URL is https://:
- Send HTTP POST/GET to the URL
Log: timestamp, from, subject, unsubscribe method, success/fail

Phase 3: Move

Move unsubscribed emails from Inbox to Newsletters/ maildir folder (create if needed)
Preserve read/unread flags
Run mu index after moves
Next mbsync -a syncs changes back to IMAP → visible in iOS Mail

Phase 4: Weekly Digest

Once per week (Sunday 8pm ET), compile and email a digest to ben@bensima.com:

Subject: Newsletter Filter Digest — Week of Mar 10

Unsubscribed this week: 23 emails from 14 senders

NEW senders unsubscribed:
  - Oura <no-reply@m.ouraring.com> (1 email)
  - ParkWhiz <hello@email.parkwhiz.com> (1 email)
  - Glenmoor Country Club <membership@glenmoorcc.com> (1 email)

RECURRING senders unsubscribed:
  - Marketing Co <promo@example.com> (4 emails)
  ...

To keep a sender, add to allowlist:
  echo "sender@example.com" >> ~/.config/newsletter-filter/allowlist

Failed unsubscribes (manual action needed):
  - Rumble <newsletter@rumble.com> — HTTP 403

Phase 5: Allowlist/Blocklist Management

Config dir: ~/.config/newsletter-filter/

Files:

allowlist — one email/domain per line. These newsletters stay in Inbox, never unsubscribed.
blocklist — force-unsubscribe even without List-Unsubscribe header (just move to Junk)
log.jsonl — append-only log of all actions
state.json — tracks which senders have been unsubscribed (avoid re-processing)

Pre-seeded allowlist:

# Newsletters Ben likes
@substack.com
pragmaticengineer
semianalysis
ainews
latentspace
latent.space
johndavidebert
johndavideb
curtisyarvin
graymir

# Mailing lists
chicken-hackers@nongnu.org
lists.tailrecursion.com
buffoverflow

# Transactional (never unsubscribe)
questdiagnostics.com
rippling.com
goodleap.com
apple.com

NOTE on Substack: @substack.com is broadly allowlisted because Ben likes Substack content generally. The classifier should treat all substack.com senders as allowlisted. Individual substack newsletters can be blocklisted if unwanted.

Scheduling

Sieve filtering: At delivery time (instant, server-side)
Unsubscribe + classify: Every 6 hours via systemd user timer on beryllium
Digest: Weekly (Sunday 8pm ET)

Implementation Details

Dependencies

Python 3 (stdlib: email, json, pathlib, urllib, smtplib, mailbox)
requests for HTTP unsubscribe calls (or just urllib)
No external services, no API keys

Rate Limiting

Max 10 unsubscribe requests per run (avoid being flagged as bot)
2-second delay between HTTP unsubscribe requests
Exponential backoff on failures

Safety

First run: DRY RUN mode. Classify and log but don’t unsubscribe or move anything. Send digest showing what would happen.
Require explicit --live flag to actually unsubscribe
Never delete emails, only move between maildir folders
Never unsubscribe from anything on the allowlist
All actions logged to log.jsonl

Backlog Processing

Process full backlog of ~2,400 newsletter emails
Rate limit still applies (10 per run), so full backlog will take ~40 runs (~10 days at 6h intervals)
Could add a --backlog flag that increases rate limit for initial cleanup (e.g., 50/run = ~2 days)

iOS Mail Compatibility

Moving files in maildir + mbsync sync means changes appear in iOS Mail automatically
Newsletters/ folder will appear as an IMAP folder in iOS Mail
No special iOS configuration needed

mu Integration

After moving files, run mu index to update the search database

mbsync Interaction

Moving files locally in maildir and running mbsync -a will sync changes back to IMAP server
Newsletter/ folder will be created on server too

File Structure

Omni/Cloud/Mail/NewsletterFilter.py   # Main script
Omni/Cloud/Mail/newsletter-filter.sieve  # Server-side sieve rules (optional)

The script should be a single-file Python script with no external dependencies beyond stdlib + requests.

CLI:

python NewsletterFilter.py --dry-run     # Classify + report, no actions
python NewsletterFilter.py --live        # Classify + unsubscribe + move
python NewsletterFilter.py --digest      # Generate and send weekly digest
python NewsletterFilter.py --backlog     # Higher rate limit for initial cleanup

Deployment Plan

Write Python script with dry-run mode
Deploy sieve rules for ongoing filtering
Run dry-run, send Ben the report
Review allowlist with Ben
Run with --live flag
Set up systemd timers