Product engineer · Germany · Remote · direct by default

I design and build SaaS products, internal tools and mobile apps

I like difficult software, plain language and visible proof. I can own product structure, UX, frontend, backend, data, deployment and release hardening—especially when a messy workflow needs to become calm, reliable software.

See relevant projects Discuss a project

Personal rule Say what is built. Say what is missing. Then do the work.

SaaS productsAuth · billing · dashboards

Internal toolsWorkflows · roles · reporting

Mobile appsScanning · operations · teams

Verification center: public sources, working demos and labelled private claims

Kintsugi Gate · 金継ぎDrag to orbit · minimal studio

Selected work · 作品

See the products, the thinking and the proof behind the work.

I would rather show an imperfect, labelled truth than a polished claim you cannot verify. Each project separates public proof, working prototypes, private-build evidence and roadmap work.

Verified or publicReported private buildIn developmentRoadmap only

壱SaaS platform · private · active development

workspace / qr-codes

OrganizationRotfuß Workspace

Admin context

Dynamic routesMutable target

IsolationTenant scoped

QR IDDestinationStatus

QR-0042/product/manualActive

QR-0041/support/setupDraft

QR-0040/campaign/summerDomain setup

Visual evidenceMulti-tenant QR workspacePrivate local build · audited feature status

Private build · owner-reportedPrivate evidence

接続

QR Platform

A multi-tenant SaaS platform for organizations that need branded, trackable QR codes with roles, plan limits, analytics and custom domains.

Role signalMulti-tenant architecture, domain modelling, permissions, billing-ready systems and end-to-end product ownership.

Useful forUseful for teams turning a single-user workflow into a secure SaaS product for multiple organizations.

Next.jsTypeScriptPostgreSQLPrisma

Evidence statusOrganization rolesDynamic redirectsSandbox billing

弐Developer tool · functional analysis prototype

local analysis / no upload

Release evidenceRepository report

B+

Production secret pattern.env.production · line 4

Fix before release

Missing CI release gate.github/workflows

Add verification

✓

Tests discoveredEvidence linked to files

Passed

Visual evidenceEvidence-first repository reportWorking local analysis demo · architecture evidence

Working demo · locally testableOpen proof

検査

RepoReady

A developer tool that turns repository and release risks into evidence-backed findings, severity levels and concrete next actions.

Role signalDeveloper tooling, explainable analysis, product judgement, deterministic rules and release-oriented engineering.

Useful forUseful for teams blocked by release risk, unclear technical debt or analysis tools that create more noise than decisions.

ReactTypeScriptNode.jsGitHub API

Evidence statusArchitecture specificationBrowser repository analysisCLI productization

参Native macOS utility · public source · source-buildable

記

Capture a thoughtStays above the current workflow

Remember to simplify the onboarding state…

Product ideaFollow-upArchitecture

Visual evidenceNative capture workflowPublic repository · independently inspectable source

Public source · externally checkedOpen proof

記憶

HoldThatThought

A public native macOS utility that captures thoughts through a global shortcut without interrupting the current workflow.

Role signalNative Swift and SwiftUI implementation, focused UX, local reliability, public documentation and source-level accountability.

Useful forUseful for focused desktop utilities or workflow accelerators where speed, privacy and low interaction cost matter.

SwiftSwiftUIAppKitLocal persistence

Evidence statusPublic source repositoryNative menu-bar workflowLocal reliability model

肆Operational mobile app · private · active development

WarehouseStock workflow

⌗

Camera scanArticle identifiedWALL4 · steel assembly

Available stock18

Last movement+4 received

Minimum thresholdHealthy

CONNECTED WORKFLOWScan → confirm → persistSupabase-backed movement historyThreshold state shown immediately

Visual evidenceScan-to-stock mobile workflowPrivate internal build · reported operational workflow

Private build · owner-reportedPrivate evidence

在庫

Warehouse App

A mobile inventory tool for warehouse teams that need fast scanning, clear stock movements, low-stock visibility and operational history.

Role signalFlutter, operational UX, scanning workflows, state management, backend integration and mobile-first product decisions.

Useful forUseful for inventory, warehouse or field workflows where every extra tap slows down real physical work.

FlutterDartRiverpodSupabase

Evidence statusArticle catalogStock movement historyCamera QR scanning

Verification center · 検証

Claims should be inspectable—or clearly labelled as private.

Public proof links to the original source. Local proof links to working programs. Everything else is marked as private evidence or roadmap work.

Last externally checked20 July 2026Public evidence review

Independent public source

GitHub identity

This portfolio openly identifies its linked public GitHub profile, where visitors can inspect repositories independently.

Public sourceOpen GitHub profile

Public product evidence

HoldThatThought source

The public repository documents the native macOS workflow, local persistence, tests, privacy behavior, MIT license and current limitations.

Public sourceInspect public repository

Directly usable evidence

Working browser demos

The portfolio includes functional local-first tools that visitors can use directly without receiving private source or release metadata.

Working demoOpen working demos

Claim discipline

No fabricated proof

No invented clients, revenue, user counts, testimonials or production screenshots. Private and roadmap claims remain visibly labelled.

Private evidenceRead verification policy

Public sourceOriginal third-party-hosted repository or profile.

Working demoRuns locally in this portfolio and is covered by tests.

Private evidenceNot publicly inspectable; available for a private walkthrough where appropriate.

○RoadmapPlanned or incomplete and never counted as shipped.

Request a private evidence walkthrough

Recognize a similar product or workflow problem?Start with a short brief. You do not need a finished specification.

Start a project brief

Working demos · 実験

Try the kind of small, useful tools I enjoy building.

Generate QR codes, inspect a repository, audit HTML and manage inventory. They are intentionally practical, local-first and honest about what they do.

Preparing the product lab…

Services · capabilities

Bring the difficult part. I will help make it understandable and shippable.

I can own the full path from product structure to release, or focus on one stubborn part. I prefer clear decisions, direct feedback and no mystery around ownership.

造01

SaaS products

Authentication, organizations, roles, subscriptions, dashboards, admin tools, data models and production deployment.

Discuss this service

業02

Internal business tools

Inventory, approvals, reporting, permissions and operational workflows designed around the way a team actually works.

Discuss this service

携03

Mobile applications

Flutter or native workflows for scanning, field work, warehouse operations, team access and backend integration.

Discuss this service

修04

Technical audits and rescue

Performance, architecture, release blockers, unreliable flows and difficult bugs turned into clear priorities and fixes.

Discuss this service

For hiring teams and clients · 判断

Decide quickly whether I fit the role or the problem.

No long sales funnel and no recruiter treasure hunt. Choose the path that matches your decision, inspect the relevant proof and move forward only if the fit is real.

For hiring teams

Review the role fit without decoding the whole portfolio.

I am strongest in remote product-engineering roles where I can own a meaningful slice of the product and stay close to the result.

Best-fit roles: Product Engineer · Full-Stack Developer · product-minded Software Engineer
Work setup: Germany · 100% remote · async-friendly written decisions
Ownership: Product structure, UX, frontend, backend, data, deployment and release hardening
Fastest proof: Public Swift repository, working browser demos, case studies and release verification

Open one-page profile Download ATS text

For founders and teams

Check whether I fit the product problem before starting a sales call.

I am most useful when the work has real product logic, operational complexity or a difficult technical boundary—not just a visual refresh.

Best-fit work: SaaS products, internal tools, operational mobile apps and technical rescue
Good starting point: A real workflow problem, a blocked release or a product that needs a dependable first version
Delivery style: Scoped first milestone, visible decisions, working increments and explicit limitations
Risk control: No hidden ownership, no invented certainty and a direct answer when the fit is wrong

Start a client brief Ask one direct question

Remote by designGermany · written handoffs · clear ownership

Proof before claimsPublic source, working demos and labelled private work

Low-surprise collaborationRisks and missing information are surfaced early

End-to-end thinkingProduct decisions stay connected to implementation and release

Quick review routeProfile → one case study → one proof source → conversation

How I work · 人柄

I work best when the problem is real, the conversation is direct and somebody owns the result.

I like turning complicated systems into calm products. I write decisions down, say when I am unsure and would rather expose a limitation than dress it up.

My operating line
“A promise should mean something. If I get it wrong, I say it early, fix it and leave the system clearer than I found it.”

My defaultBe direct, be kind and keep the promise.

When I am wrongSay it early, fix it and document what changed.

What I avoidInflated claims, vague ownership and meetings without decisions.

What I enjoyDifficult workflows, quiet interfaces and software that earns trust.

Off screenTraining, building in Minecraft and sketching the next product idea.