darkzwarmer

What it does

Controls

Configuration includes inbox counts, sending windows, send delays, reply delays, steady-state volume, and an optional per-inbox daily send ceiling.checked 7 Oct 2026

Cross-domain sending

Inboxes send to inboxes on other configured domains; same-domain pairs are not used.checked 7 Oct 2026

Cross-domain traffic

Each inbox sends only to inboxes on other domains, and the tool does not use same-domain pairs.checked 7 Oct 2026

Expansion

Optional wave cohorts can add inboxes automatically on a configured schedule, with new inboxes starting at Day 1.checked 7 Oct 2026

Inbound integrations

Inbound mail can be received through IMAP or Resend; the Resend setup uses a Vercel webhook and an Upstash Redis queue.checked 7 Oct 2026

License and warranty

The project is MIT-licensed and provided as-is without warranty.checked 7 Oct 2026

Operating systems

The README describes unattended operation on Windows and running under process managers on Linux and macOS.checked 7 Oct 2026

Operating system support

The README provides unattended-operation scripts for Windows and says Linux and macOS users can run the process under a service manager or terminal session.checked 7 Oct 2026

Purpose

darkzwarmer generates inboxes across user-provided domains, sends warmup email between those inboxes, and replies after human-like delays.checked 7 Oct 2026

Replies

The network waits a random 30 minutes to 4 hours before replying in-thread to its own messages, and ignores outsider mail.checked 7 Oct 2026

Reply behavior

The tool replies to its own network’s messages after a random 30-minute to 4-hour delay and ignores outsider mail.checked 7 Oct 2026

Requirements

It requires Python 3.11 or later, at least two user-owned domains for cross-domain traffic, an outbound SMTP provider, and a way to receive mail.checked 7 Oct 2026

Responsible use

The maker says the tool only emails its own network and is intended for domains and mailboxes the user owns and controls.checked 7 Oct 2026

Runtime

The project requires Python 3.11 or later and an always-on machine, and stores state in SQLite.checked 7 Oct 2026

Scheduling

Sends are randomized across a default 07:00–19:00 local window, with 2–8 minutes of jitter between an inbox’s consecutive sends; weekends are paused.checked 7 Oct 2026

Security and credentials

The README says secrets are supplied through environment variables, and identifies .env, catch-all credentials, and the SQLite database as git-ignored files.checked 7 Oct 2026

Security practices

The Resend webhook verifies request signatures, while SMTP, Resend, Upstash, and IMAP credentials are configured locally and credential files are gitignored.checked 7 Oct 2026

Self-hosting

The project describes itself as a Python runtime backed by SQLite that users run on an always-on machine or VPS.checked 7 Oct 2026

Sending integrations

Outbound delivery uses configurable SMTP and the README lists Amazon SES, SMTP.com, Postmark, Mailgun, Brevo, and SendGrid as examples.checked 7 Oct 2026

SMTP integrations

Outbound sending uses configurable SMTP; listed providers include Amazon SES, SMTP.com, Postmark, Mailgun, Brevo, and SendGrid.checked 7 Oct 2026

State and recovery

SQLite stores runtime state, and the README says the tool resumes after crashes or reboots and prevents duplicate replies with a unique index.checked 7 Oct 2026

Usage limits

A per-inbox daily send ceiling can be configured, and the README notes that provider rate or quota limits can cause send failures.checked 7 Oct 2026

Warmup ramp

Per-inbox volume increases from 5 to 35 messages per day over 28 days, then stays at the steady-state level.checked 7 Oct 2026

Warmup schedule

Per-inbox sending volume ramps from 5 to 35 messages per day over 28 days, then stays at the steady-state volume.checked 7 Oct 2026