Senior Fullstack · Solo Builder

Adrian Kujawski

I ship AI-native products solo — Flutter + Go + LLM integration.

Native Polish · Fluent English · Worked with Danish healthcare + US corporations

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FLUTTER GO LLM INTEGRATION POSTGRES PRODUCTION-GRADE INFRA

Featured Work — Live

Geo Duelist

Real-time PvP with LLM-driven shape personalities. Every triangle remembers its last 5 fights.

A game I built solo end-to-end: Flutter web/iOS/Android, a Go backend with WebSocket matchmaking, PostgreSQL for shape memory, and Groq (llama-3.3-70b) for personalities. Zero infra cost on the free tier. The LLM interface is provider-swappable — switch to Ollama, Claude, or OpenAI with one line of code. Now shipping a second mode: Heroes 3-style hex combat with the same LLM personalities reacting to your tactical decisions turn by turn.

Flutter Go Groq LLM PostgreSQL Turn-based

● Last shipped: 2026-07-15 · Working on hex combat expansion

What You Get

Hiring a contractor is a bet on speed and reliability. Here's the specific bet you’re placing.

Ship a feature without staffing three people

Database schema through Flutter animation, one senior contractor end-to-end. No handoff bugs, no sync overhead, no "waiting on the other team." Ten years across mobile, web, and backend.

Adopt LLM features without vendor lock-in

Provider-swappable architecture with rate limiting, structured output validation, and graceful degradation to curated static responses when the model is down. Swap Groq for Claude, Ollama, or OpenAI with one line of code.

Sleep through your deploys

Every project I ship exposes /health returning the built commit SHA — CI fails loud if the wrong version is live. Feature flags for gradual rollout, kill switches for anything AI-related, silent stale deploys stopped biting me two years ago.

Selected Work

A slice of what I’ve shipped before Geo Duelist — from factory floors to trading desks.

Manufacturing · MES

Real-time monitoring for Poland’s biggest food factories

Senior Flutter developer on a MES app pushed to production lines that run 24/7. Live dashboards, real-time reporting, and mentoring other Flutter devs across parallel projects.

Flutter Real-time Mentoring

Healthcare · Denmark / US

HIPAA-grade mobile app across two continents

Delivered with a US corporation for the Danish healthcare market. Cross-border data compliance, real-time patient sync, and a 30% cut in app load time through targeted profiling. Team of five Flutter devs.

Flutter HIPAA GDPR Perf

E-commerce · 50k+ downloads

Checkout that converts at 95% on mobile

A Flutter e-commerce app with 50,000+ installs. Iterated the checkout flow with A/B tests until mobile completion sat at 95%. Owned state management, CI/CD, and the backend seams.

Flutter A/B testing CI/CD

Fintech · Real-time trading

Forex trading systems where milliseconds matter

High-frequency Forex execution on .NET Core with SignalR live market feeds. Financial-grade auth, sub-second latency, and end-to-end ownership on a small fullstack team.

.NET Core SignalR HFT

How We Work Together

From first email to signed contract in about a week. Three steps, zero surprises.

01

30-min discovery call

Book a slot. We’ll cover what you’re shipping, timeline, technical constraints, and whether I’m the right fit. No sales pitch, no obligation.

02

Discovery sprint (2 weeks, fixed price)

If we click, we start with a 2-week paid sprint. Output: scope, roadmap, and the first shipped feature. You walk away with real work whether you continue or not.

03

Delivery sprint or retainer

From there we either commit to a fixed-price delivery sprint (4-8 weeks, defined scope) or an ongoing retainer (3-6 months, 20-30h/week). Your choice, based on how the discovery went.

Engagements

Three ways to work with me. All EUR, excluding VAT. Pick your entry point.

Discovery Sprint

from €5,000

2 weeks. Scope + roadmap + first shipped feature. Low-risk way to test the working relationship.

  • Kickoff call + architecture review
  • 1 shipped feature or POC
  • Written recommendations for next 30 days
MOST COMMON

Delivery Sprint

from €30,000

4-8 weeks, fixed scope. MVP or a complete feature end-to-end. Best for a defined outcome with a hard deadline.

  • End-to-end delivery: DB → API → mobile
  • Deployed to production, monitored
  • 2 weeks of post-launch support included

Retainer

from €12,000/mo

3-6 months starter, 20-30h/week. Ongoing partnership for teams that want a senior on tap without a full-time hire.

  • Async-first, EU timezone friendly
  • Weekly demo + written status
  • Renewable every 6 months, 30-day notice

The Fine Print

Common questions before we talk.

NDA before discovery call?

Happy to sign a mutual NDA before we discuss anything technical. Send yours, or I have a template ready.

Who owns the code?

You do. Full IP transfer on delivery, standard. Written into every contract.

How do you invoice?

Monthly, in EUR. EU B2B reverse charge VAT (client handles VAT locally). Non-EU: gross invoicing. Poland-based JDG, valid VAT-EU registered.

Can I talk to a past client?

Happy to connect you with references on request after our first call. Not before — respecting their time.

How do you communicate?

Async by default — Slack, Linear, GitHub. Video calls only for kickoff and mid-sprint check-in. Written status updates weekly.

Adrian Kujawski presenting

Open for Contract Work

Have a product to ship?

I take on 1–2 concurrent clients. Preferred setup: 3–6 month engagements, 20–30h per week, EU timezone friendly.

Reply within 24h · EU business hours (Mon-Fri 9-17 CET)

Available for kickoff: October 2026 · 1 slot open Q4

Book a 30-min call → Or email [email protected]

or reach me on LinkedIn ↑