Justin Lanfermann · Software Engineer · Munich

I build software people actually use.

Indie iOS apps, web products, and AI experiments, shipped from Munich.

I'm the developer behind NeatPass, the PDF-to-Wallet app featured by Apple. I study computer science at TUM, tutor CS from intro programming to systems-level courses, and write about what I learn shipping real products.

See what I ship Read the blog

Need an engineer? I take freelance projects

NeatPass

iOS appGym MembershipJ. Lanfermann

Featured by Apple · 21,000+ users

Swipe a card, or tap it to visit

"Apps We Love" · Apple feature21,000+ NeatPass users300,000+ passes created4.5★ on the App StoreCovered by heise onlineTop 8% · CS @ TUMHead of Software Dev @ TUM.ai

Products

Things I've shipped

Real products with real users, designed, built, and launched solo.

iOS app

NeatPass

PDF to Apple Wallet, fully on-device

Airlines, gyms, and ticket shops send PDFs. Apple Wallet wants passes. NeatPass converts any PDF into a Wallet pass directly on the iPhone, with on-device AI and zero uploads.

Apple featured it in "Apps We Love" and is building the concept into iOS 27 as a system feature. I shipped it first.

Explore NeatPass

Users

21,000+

Real people, every day.

Passes created

300,000+

All generated on-device.

App Store rating

4.5★

From 194 ratings.

Apple feature

Apps We Love

Picked by Apple's editors.

Currently

What I'm up to

Teaching at TUM

CS tutor at TUM, helping 250+ students with everything from intro programming to operating systems and networks.

Leading software at TUM.ai

Head of Software Development at Europe's leading AI student initiative.

Open for freelance

Focused on a few projects at a time: web, iOS, and AI. Remote or on-site in Munich.

Writing build logs

Deep dives and write-ups on systems, AI, and what shipping products actually takes.

Blog

Latest writing

Build logs, deep dives, and the occasional hot take.

Experience

Where the Community Comes Home: Two Days With Six Years of TUM.ai

Seventy-seven people, twelve batches, and two days in the Bavarian Alps. The TUM.ai retreat was the first time I met the alumni who turned a 2020 group chat into the thing I help run today.

Build the Most Absurd Thing: An Onboarding Hackathon with a Squabbling AI Council

Thirty-five new TUM.ai members, a weekend away, and two hours to build the most absurd thing they could. I designed the format and a panel of squabbling AI personas that pelted each team with bonus challenges, while the room voted on the winner.

Making NeatPass: From an Annoying PDF Ticket to an App

An annoying party ticket PDF became a privacy-first iOS app: an AI brain that runs entirely on your phone, signing Wallet passes without ever seeing their contents, and the decision against every subscription.