Lead Software Engineer on the Email Platforms team at Klaviyo. I have more than 20 years of experience in backend development, distributed systems, databases, systems operations, and networking. I also led teams for SaaS, AI/ML, and data platforms. I live in Boston, MA.
- 🔭 Now: at Klaviyo, I build the systems that deliver email reliably at high volume
- 🛠 Before: Director of Engineering at DataRobot (MLOps and Governance), CTO and co-founder of Ubivox (newsletter platform)
- 🌱 My spare-time projects are about SMTP, DNS, and networking. See the list below
- 📫 christian@technobabble.dk · linkedin.com/in/joergensen · technobabble.dk
These are hobby projects outside of work, for fun.
Conduit: a self-hosted gateway from email to webhook, built on
smtpd. Conduit converts inbound mail into an HTTP POST request. The response from the webhook
maps to an SMTP status code. Then the remote mail server does its own retries.
ZeroDrop: free uptime monitoring from multiple locations. A control plane in Go controls distributed agents over a WireGuard mesh. The agents test HTTP, TCP, and TLS. The agents must agree before ZeroDrop sends an alert.
Doctor Whois: a small single-page application and REST API with network and cryptography tools.
| Package | Description |
|---|---|
| smtpd | Build SMTP servers with STARTTLS, authentication, XCLIENT, and HELO/RCPT/DATA checks |
| pflog | Parse Postfix mail logs into Go structures |
| wgnet | Build user-space services inside WireGuard VPNs |
| ssrf | Prevent SSRF in http.Transport |
| keyrate | Rate limiters with a key (per user, per IP), based on x/time/rate |
| diggity | DNS health checker: delegation, TTLs, DNSSEC chain of trust, cross-server answers |
| vanguard | Prometheus black-box exporter (HTTP/TCP/SSH/SMTP) that operates over WireGuard |
| ircbot | Asynchronous IRC bot framework for Rust, built on Tokio and proc macros |
| dmarc-report-parser | Parse DMARC aggregate feedback reports (Rust library and CLI) |
| prometheus-dnssec-exporter | Monitor DNSSEC and RRSIG expiration |
| prometheus-ssl-exporter | Monitor SSL certificate expiration and connectivity |
More at technobabble.dk.