Krueger — Product Engineer

Selected work

Ten products. One operator.

Each one shipped, deployed, and operated as production software — not coursework or proofs of concept. Filter by surface to see how the stack changes with the problem.

01 LIVE

DISBET

Consumer-Friendly Crypto Casino

A crypto casino built for play, not protocols. 30+ games — Crash, Dice, Mines, Plinko, Blackjack, Roulette, slots, and more. Instant deposits, live chat with rain rewards, a Discord bot linked to your account, tournaments, referrals, and a built-in multi-asset wallet. Fair by default, never a lecture.

Casino 30+ Games Discord Tournaments Instant Deposits Community

Live App Case Study

02 LIVE

Rippet

Mystery TCG Pack Opener

Rippet turns card collecting into a fast browser loop: rip mystery packs, reveal five-card pulls, collect duplicates, claim daily shards, and sell cards back instantly through a rarity-floor market. A provably fair HMAC-SHA256 engine powers every rip.

TCG Packs Provably Fair Collection Market Node Postgres

Live App Case Study

All Products

03 LIVE

SimDex

Market Intelligence Tooling

Market tooling with faster information flow, stronger context, and real execution-adjacent depth. Board, wallet, Dex, room, company surfaces with quote preview, swap build, auth, bookmarks, and social tools.

Finance Real API Dense UI Speed

Live App Case Study

04 BUILT

SPUF

HWID / TPM Kernel-Level Spoofer

Hardware identity spoofer with kernel driver integration. Deterministic seed-based spoofing across 107 identifiers — disk serials, SMBIOS, GPU, MAC, registry, EFI, and TPM 2.0 emulation. Anti-forensics pipeline with automated trace removal.

WPF .NET 10 C# Kernel Driver HWID TPM

Download Case Study

SPUF

K R U E G E R

05 LIVE

SwiftBill

SaaS Invoice Generator

Freemium invoice generator built with Next.js 16 and Supabase. Create, manage, and export professional invoices as PDF. Stripe subscription billing, Google OAuth, live preview, and dashboard analytics.

Next.js 16 Supabase Stripe SaaS

Live App Case Study

swiftbill.app

12INVOICES

$4.8KREVENUE

$890PENDING

#0012PAID

#0011SENT

#0010DRAFT

06 LIVE

TapCard

Digital Business Card Platform

Digital business cards with NFC tap and QR sharing. Real-time analytics, contact capture, instant updates, custom domains, and Apple/Google Wallet support. Free, Pro ($5/mo), and Teams ($8/user/mo) tiers.

Next.js NFC QR SaaS

Live App Case Study

TAPCARD

KRUEGER

Product Engineer

[email protected] tapcardapp.com/krueger Pacific / Remote

07 LIVE

TapBio

Link-in-Bio Platform

Link-in-bio platform for creators and professionals. Unlimited links, custom themes, click analytics, and mobile-first design. Free, Pro ($5/mo), and Teams ($8/user/mo) tiers. Built with Next.js and Tailwind CSS.

Next.js Tailwind CSS Analytics SaaS

Live App Case Study

@KRUEGER

Product Engineer · Builder

PORTFOLIO

SIMDEX

SWIFTBILL

CONTACT

TAPBIO

08 LIVE

SwiftLead

Lightweight CRM

CRM built for freelancers and small teams. Contact management, visual deal pipeline, activity timeline, smart reminders, CSV import/export. SwiftBill integration for deal-to-invoice workflow. Free, Pro ($9/mo), and Teams ($15/user/mo).

Next.js 15 Supabase CRM SaaS

Live App Case Study

app.swift-lead.net

128CONTACTS

24DEALS

$14KREVENUE

LEAD

Acme Co

$2.5K

Nova Inc

$1.8K

CONTACT

Bolt Labs

$4.2K

PROPOSAL

Spark IO

$8.5K

WON

Apex Ltd

$6K

Vex Co

$3.2K

09 LIVE

VFX Studio

Interactive WebGL Scene Playground

Type a prompt, get a scene. Real-time WebGL playground with 14 shapes, 11 palettes, 8 style packs, 7 render engines, and a custom GLSL fragment shader editor. Audio-reactive (mic or upload, with Web MIDI binding), camera path recorder, post FX stack, and one-click PNG / WebM / GIF export. State persists in localStorage and shares via URL hash.

WebGL Three.js React GLSL Audio-Reactive Web MIDI

Live App Case Study

10 ARCHIVED

Kineo

Guided Wellness Platform — Discontinued

Former project. Browser-first PWA with account sync, structured health workflows, coaching, nutrition, and scanner surfaces. Development discontinued — skills carried forward.

PWA Health Coaching Installable

Case Study

Engineering Principles

Six rules that shape every release.

Doctrines learned from shipping ten products solo. Some hold across the field; some are mine. All of them are non-negotiable.

01 / Release

Ship behind flags.

Every meaningful change lands gated. Production is opinionated; rollouts are not. Reverting a feature flag beats reverting a deploy.

02 / Performance

Measure before you optimize.

No optimization without a baseline. Numbers beat instincts; instincts beat unmeasured optimizations that ship for no one.

03 / Stack

Prefer boring tech.

Postgres + Node will outlive the framework du jour. Reach for novelty only when it pays its tax in capability or speed.

04 / Surface

Own the full stack.

From kernel driver to landing page. The seams between engineers are where the bugs live, and where the experience falls apart.

05 / Quality

Release-ready by default.

If it can’t ship today, it isn’t done. Half-state is debt. Branches that don’t merge in a week were never going to.

06 / Judgment

Optimize for ambiguity.

Writing code is the easy part. The hard work is deciding what to build, what to delete, and what to leave alone.

Skills Matrix

What I’ve actually shipped with.

Not a tag cloud of buzzwords — a working register of tools used in production code, with proficiency calibrated against shipped surface area.

Languages

TypeScript / JavaScript

All web surfaces · 6+ years

C# / .NET

SPUF · WPF · .NET 10

SQL (Postgres)

Daily · transactional + analytical

C / Kernel

SPUF kernel driver · WDK / WDM

GLSL

VFX Studio shader editor

Python

FastAPI services · ReportLab PDF

Frameworks & Libraries

React / Next.js

SwiftBill / SwiftLead / TapCard / TapBio

Three.js / @react-three/fiber

VFX Studio · WebGL pipelines

Node / Express

Rippet provably-fair engine

FastAPI

SimDex market services

React Native / Expo

Kineo PWA / mobile flows

Vite / Webpack

Build pipelines · lazy chunks

Infrastructure

Cloudflare Pages / Workers

Edge deploy · security headers

Supabase / Postgres

Auth · RLS · transactional schema

Stripe

Subscription · one-time · webhooks

Render / Vercel / Railway

Multi-service deploy + cutover

Custom DNS / TLS / Domains

Production cutover playbook

CI/CD (GitHub Actions)

Build / test / deploy pipelines

Practices

System / API design

REST · webhooks · auth flows

Performance engineering

Profiling · bundle · render perf

Provably-fair / cryptography

HMAC-SHA256 commit/reveal

Real-time / WebSockets

Live chat · betting feeds

Browser QA (Playwright)

E2E · visual regression · nav

Product / interface architecture

Routes · states · release polish

How I Work

Five steps. No detours.

The loop that takes a product from blank canvas to live URL. Same shape whether the surface is a SaaS dashboard, a kernel driver, or a WebGL playground.

Frame

Name the problem in one sentence. Decide what a finished version looks like before opening an editor.

Architect

Sketch routes, data shape, state boundaries, deploy surface. Boring tech wins by default.

Prototype

Build the smallest end-to-end slice that proves the loop. Visible UI on day one, not week three.

Ship

Deploy behind a flag, custom domain, security headers, monitoring. Production from the start.

Operate

Measure usage, fix sharp edges, write the changelog, hand off the runbook. The work isn’t done at deploy.

I architect, ship, and operate consumer + B2B products end‑to‑end.

Ten products. One operator.

DISBET

Rippet

SimDex

SPUF

SwiftBill

TapCard

TapBio

SwiftLead

VFX Studio

Kineo

Six rules that shape every release.

Ship behind flags.

Measure before you optimize.

Prefer boring tech.

Own the full stack.

Release-ready by default.

Optimize for ambiguity.

What I’ve actually shipped with.

Languages

Frameworks & Libraries

Infrastructure

Practices

Five steps. No detours.

The day-to-day toolkit.

Currently available for select work.