The bulk mailer built for operators, not subscriptions.
Desktop GUI. Full-power CLI. 50+ dynamic placeholders, 8 attachment formats, Exchange/OWA support and 2026-compliant inbox-signal headers — one self-contained tool. You own the sending.
Ten reasons operators pick DukeMailer.
Every feature is built around one idea: you keep control of the sending, the data and the tool.
GUI + CLI, one engine
A polished Electron desktop app and a raw command-line tool — same sending core, different surface.
50+ dynamic placeholders
Per-recipient tokens for names, dates, domains, QR codes, random data — every email is unique.
Round-robin SMTP rotation
Balance load across unlimited SMTP profiles with automatic fallback and graceful stops.
8 attachment formats
HTML, EML, DOCX, PDF, RTF, EPUB, ODT, SVG — generated on the fly, per recipient.
2026 inbox headers
Identity, reputation, ML/AI, anti-phishing and provider-specific Gmail & Microsoft signals.
Exchange / OWA native
Office 365, on-prem, hybrid — Basic, NTLM and Bearer auth, like a first-class client.
Built-in QR codes
Per-recipient QRs, custom size, custom colors, palette randomization. No third-party service.
Auto domain logos
Recipient's real company logo embedded in every mail via a 4-level resolution fallback.
Hardware-bound license
No seat sharing, no leaks. CPU, disk and NIC fingerprint stored in a JWT you own.
Portable .exe / .dmg
Zero install. Works air-gapped. Windows and macOS binaries plus a standalone CLI EXE.
Desktop GUI
Electron + React 19 + Tailwind + Framer Motion. Dashboard, Leads Manager, Composer, Global Settings, Live Logs.
- Live stat cards & real-time delivery feed
- Drag-drop leads (.txt / .csv) with regex email extraction
- Editor / preview with iPhone mockup
- SMTP profile manager with per-profile modal
- Full-session campaign logs, monospace timestamps
CLI Mode
Full-featured for server and headless environments. Same engine, scripted for automation.
- All 8 attachment formats
- Exponential backoff retry
- 240+ custom headers from config.js
- ZIP + encrypted ZIP bundling
- Debug (--inspect) and watch mode
##placeholders##
that make every email unique.
Recipient-derived values, date and time, random data pools, dynamic patterns (##num6##, ##stringupper13##), and configurable QR codes — all resolved per-recipient at send time.
Eight formats. Generated per recipient.
On-the-fly rendering with placeholder-resolved filenames. Attachments force direct SMTP delivery, bypassing the API relay when maximum authenticity matters.
Inbox signals engineered for modern filters.
Every email ships with a full suite of headers built to pass Gmail, Microsoft and enterprise ML classifiers — plus conditional provider-specific signals based on recipient domain.
Identity
- — Unique Send ID + Session ID
- — Rotating mailer client (12 real names)
- — Rotating browser User-Agent
Reputation
- — X-Sender-Reputation 97–100
- — X-Domain-Reputation excellent
- — X-Warmup-Status completed
ML / AI bypass
- — X-ML-Score 0.010–0.050
- — X-Neural-Classification ham
- — X-Content-Trust-Score 95–100
Anti-phishing
- — X-Phishing-Score 0.00
- — X-Brand-Indicator verified
- — X-Credential-Phishing-Verdict pass
Compliance
- — X-Consent-Verified true
- — X-Consent-Source explicit-opt-in
- — X-Transactional true
Provider-specific
- — Gmail: X-Google-DKIM, X-Gm-Message-State
- — Microsoft: X-MS-Exchange SCL -1
- — X-MS-Exchange-AtpMessageProperties
DukeMailer Pro vs typical SaaS mailers.
Ships as one file. Runs anywhere.
Portable Windows and macOS binaries plus a self-contained CLI EXE — no Node.js runtime required. App ID com.dukemailer.pro.
Stop operating blind on office leads.
Most sorters lump everything into one generic Office category. That's lazy segmentation — and lazy segmentation kills campaigns. Our system identifies the actual MX and security layer behind each address.
The generic approach
Basic "Office domain" filters label everything the same. If you're sending the same message, same structure, same links to all of them — you're leaving money on the table.
The DukeMailer sorter
Identifies and differentiates the actual MX and security layer behind each address — so you know exactly what infrastructure you're sending into before you pull the trigger.
Detected security environments
9 layers identifiedEach environment filters, scores, and handles inbound mail differently — a single strategy across all of them is a liability.
When you know the exact infrastructure
- Adjust your sending strategy per environment
- Optimize formatting and link structure for each filter layer
- Improve inbox placement on every segment
- Protect high-value leads from being burned
- Increase campaign ROI across your entire list
Precision over guesswork.
If you're buying premium leads and treating them all the same, you're burning capital. This sorter is built for operators who care about results — not those who just hope.
Message @Duke_toolzbot · Serious marketers optimize. Everyone else hopes.
Stop renting your mailer. Own it.
No monthly cap. No cloud dependency. No API keys. Hardware-bound license, portable binaries, and a support line straight to the team.