name: Arun Kumar
role: Email Infrastructure Engineer
Full-Stack Developer
company: Sendpilots
expertise:
mta: [ Postal, Postfix, Haraka, PowerMTA,
KumoMTA, OpenSMTPD, Exim, MailerQ ]
auth: [ SPF, DKIM, DMARC, BIMI, ARC,
MTA-STS, OpenDKIM, OpenDMARC ]
filtering: [ Rspamd, SpamAssassin, Amavis,
Postscreen, ClamAV, Milter ]
testing: [ GlockApps, Mail-Tester, MXToolBox,
Google Postmaster, Microsoft SNDS ]
backend: [ PHP, Laravel, Next.js, Python ]
frontend: [ Next.js, TypeScript, Tailwind CSS ]
infra: [ Docker, Nginx, Redis, Linux ]
cloud: [ AWS, DigitalOcean, Hetzner, Cloudflare ]
automation:[ Selenium, Playwright, Python ]
billing: [ Razorpay ]
achievements:
- "🦈 Pull Shark × 2"
- "👥 Pair Extraordinaire × 3"
- "⚡ YOLO"
- "🎯 Quickdraw"
contact: arun@sendpilots.com |
|
Specialized in building, scaling, and operating high-volume email delivery systems — from raw SMTP configuration to full deliverability optimization and ISP reputation management.
| MTA | Use Case | Status |
|---|---|---|
| Postal | Open-source self-hosted MTA, full API control | ✅ Production |
| Postfix | Production SMTP relay, inbound filtering | ✅ Production |
| Haraka | Custom SMTP plugin development (Node.js) | ✅ Production |
| PowerMTA (PMTA) | Enterprise high-volume sending (1M+/hr) | ✅ Experienced |
| KumoMTA | Modern high-performance Rust-based MTA | 🔧 Working |
| OpenSMTPD | Lightweight deployments, filtering chains | 🔧 Working |
| Exim | cPanel environments, custom routing rules | 🔧 Working |
| MailerQ | Queue-based sending with REST API control | 📚 Studying |
🔍 Expand — Full Deliverability Stack
IP & Domain Reputation
- 🔥 IP Warming — Gradual ramp 0 → 1M+/day with schedule automation
- 📈 Reputation scoring via Google Postmaster Tools & Microsoft SNDS
- 🌐 Dedicated IP pools — Segmenting transactional vs marketing traffic
- 🔄 IP Rotation — Automated failover on reputation degradation
Bounce & Complaint Management
- Hard bounce processing & permanent suppression lists
- Soft bounce retry with exponential backoff (SMTP 4xx handling)
- Feedback Loop (FBL): Yahoo, Outlook/Microsoft JMRP, AOL
- Complaint rate thresholds & auto-suppression (target < 0.08%)
Blocklist Management
- Real-time: Spamhaus ZEN/DBL, Barracuda, SURBL, URIBL, MXToolBox
- Automated delisting request workflows
- Pre-warming blocklist checks & IP history audit
Inbox Placement & Testing
- Seed list testing across 100+ mailbox providers
- Spam folder detection & content score analysis
- Full header tracing & routing path audit
- DMARC aggregate report (RUA) parsing & alerting
ISP Relations & Compliance
- Gmail Postmaster Tools (Domain/IP rep dashboards)
- Microsoft SNDS + JMRP (Junk Mail Reporting Program)
- Yahoo/AOL Complaint Feedback Loops
- Apple MPP (Mail Privacy Protection) — open rate normalization
- CAN-SPAM, GDPR, CASL compliance
; Complete production email DNS setup
@ MX 10 mail.yourdomain.com. ; Mail routing
mail A <SERVER_IP> ; MTA A record
mail PTR mail.yourdomain.com. ; rDNS — critical for deliverability
@ TXT "v=spf1 ip4:<SERVER_IP> ~all" ; SPF policy
_dkim._domainkey TXT "v=DKIM1; k=rsa; p=<PUBKEY>" ; DKIM public key (OpenDKIM)
_dmarc TXT "v=DMARC1; p=reject; rua=mailto:dmarc@yourdomain.com"
_mta-sts TXT "v=STSv1; id=<TIMESTAMP>" ; MTA-STS policy ID
_smtp._tls TXT "v=TLSRPTv1; rua=mailto:tls@yourdomain.com"
default._bimi TXT "v=BIMI1; l=https://yourdomain.com/logo.svg; a=..."
| PHP | Python | TypeScript | JavaScript | HTML5 | CSS3 | Bash/Shell |
|---|
| Laravel | Next.js | Node.js | Tailwind CSS | Bootstrap |
|---|
| MySQL | Redis | PostgreSQL | SQLite |
|---|
| Docker | Nginx | Linux | Ubuntu | Git | GitHub | Actions | AWS |
|---|
| AWS | Cloudflare | DigitalOcean |
|---|
| Grafana | Prometheus | Postman | VS Code | Vim |
|---|
| Selenium | Playwright |
|---|
Building Sendpilots — production-grade email delivery infrastructure that makes high-deliverability email accessible to every developer.
[██████████░░░░░░░░░░] 50% Scale Sendpilots → 10M+ emails/day
[████████░░░░░░░░░░░░] 40% Real-time deliverability monitoring dashboard
[██████████████░░░░░░] 70% Zero-bounce email list management
[████████████████░░░░] 80% Multi-MTA failover & load balancing
[█████████████████░░░] 85% Full SPF/DKIM/DMARC/BIMI pipeline
[████░░░░░░░░░░░░░░░░] 20% Open-source IP warming automation toolkit
[██████████████████░░] 90% Containerized MTA deployments via Docker
[██░░░░░░░░░░░░░░░░░░] 10% BIMI + VMC brand identity at major ISPs
| Goal | Target | Status |
|---|---|---|
| 🚀 Sendpilots v1.0 Production | 2025 | 🔄 In Progress |
| 📊 Deliverability Analytics Dashboard | 2025 | 🔄 Building |
| 🔓 Open-source IP Warming Tool | 2026 | 📅 Planned |
| 🌍 Multi-region MTA Infrastructure | 2026 | 📅 Planned |
| 🏆 Contribute to Email Auth Standards | Ongoing | ✅ Active |
| Badge | Achievement | Earned By |
|---|---|---|
| 🦈 | Pull Shark × 2 | Opened PRs merged into external repos |
| 👥 | Pair Extraordinaire × 3 | Co-authored commits with teammates |
| ⚡ | YOLO | Merged PR without review — move fast |
| 🎯 | Quickdraw | Fast PR response & issue closure |
Open to collaborating on email infrastructure, deliverability tooling, and Laravel/Python projects.
