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 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.