Software engineer & consultant · Oslo, NO

Kristoffer
Opsahl

Backend, distributed systems & security. I design event-driven services with Java & Spring Boot, Apache Kafka, and Elixir & Phoenix.

TypeScriptApache KafkaAzureGoDockerPhoenixGCPLinuxKubernetesPostgreSQLRustJavaElixirSpring BootKotlinReact

Latest

all →
2026-04-03

How to Securely Erase a Hard-Disk Drive

LinuxNote
2025-12-07

Coding Agents Need Deterministic Feedback: A Case for Phoenix

AIElixir
2025-09-14

Using dd to Write an .iso to a USB Drive

LinuxNote
2025-07-07

My Alacritty, Zellij, and Helix Development Setup

ToolingNote
2025-04-29

Breaking AES-ECB with an Encryption Oracle Attack

SecurityCryptography
2025-04-22

3rd Prize at TG:HACK

SecurityCTF
2025-03-25

Java's Optional Has a Problem

Java
2025-03-07

From Zero to Hello World with Apache Kafka® in 2025

KafkaTutorial
2025-03-06

Core Concepts in Apache Kafka®

Kafka