Software development engineer who loves to code.
Returns
420nice.
Building software in fintech and healthcare.
5+ years of C# and .NET experience across HIPAA and PCI compliant systems.
2023 – now
Moberg
Software Development Engineer · Full-time, remote
From buy now, pay later to a payment facilitator that wraps Adyen for the Icelandic market.
2025 – 2026
Singleton
Software Development Engineer · Sole proprietorship, remote
Web identities for local businesses: fast, light on resources and built to get traction.
2025 – 2026
Qualify Health
Software Development Engineer · B2B contract, remote
HIPAA and SOC compliant healthcare software that matches patients with available funding.
2022 – 2023
Mono Software
Software Development Engineer · Full-time, on-site
A large European sportsbook: backend microservices, plus the performance work to keep them fast.
When a library breaks,
I report it to the maintainers.
I investigate bugs, write clear reports and contribute code changes where possible.
Adyen/adyen-web
Adyen's Drop-in and Components for web checkout
soundaranbu/Razor.Templating.Core
Renders Razor views to strings outside ASP.NET
segmentio/Analytics-CSharp
Segment's analytics SDK for .NET, Xamarin and Unity
CTFs, from first clue
to the final flag.
98 writeups from 3 competitions, written so you can follow along even if you've never played a CTF.
Capture the Flag is a cybersecurity competition. Every challenge hides a secret string, the flag, behind a weakness: a web app to break, a binary to reverse, a cipher to crack or a trail of public clues to follow. Find the flag, submit it, score points.
Each writeup here walks through one challenge, start to finish.
PwnFortID 2026
Editorial Board
A service runs submitted text through a real grammar checker, then copies it into an RWX page and jumps in. The overflow and the shellcode both have to read as clean English, so the shellcode is built out of real words.
WebFortID 2026
King Admin
A stored XSS on an admin-only page, a predictable CSP nonce, and a CSRF-exempt announcement sink let me make an admin bot mint and leak its own admin credential offer, which I then redeemed and presented myself.
ReversingHackultet 2026
QR is Life
A page claims to run Conway's Game of Life on a QR code, but the server only ever applies one step, which turns finding the flag into reversing a single step of Life under the heavy structural constraints a QR code imposes.
CryptoHackultet 2026
Hash Me If You Can
Two images each have to display text derived from the other's MD5 hash, a circular requirement that unravels the moment the two files are given the same hash on purpose.
If you like numbers.
- Years of experience
- 5+
- CTF writeups published
- 98
- Competitions played
- 5
- Bugs reported and fixed
- 8