Open to B2B subcontracting: 8-12 h/week, async (invoice, EU VAT)

Grzegorz Hul

Senior Flutter Developer, AI-augmented

I build Flutter apps and the AI features inside them. 8 years in software, nearly 7 of them at LIBRUS, Poland's largest ed-tech, with Flutter since 2021. I ship with Claude Code every day; every change is tested, and in company code every diff is reviewed by me.

Email me CV (PDF) LinkedIn GitHub
grzegorz.hul@gmail.com Poland (CET)

Projects

AnalizaPrawna

Own product

AI legal analysis platform: a ReAct agent with 8 tools over 527k Polish court rulings (pgvector, self-hosted Polish embeddings on GPU, model failover). 139 API endpoints, ~2.8k tests.

ReactTypeScriptExpressPostgreSQL + pgvectorLLM agentsPayU
Live site

Revelations

Own app

Polish-language Flutter reader of Maria Valtorta's work: user data migrated from the old Cordova app, 1,534 chapters offline, a 714-file audiobook from self-hosted TTS, ~710 tests.

FlutterRiverpodFirebaseXTTS-v2
Google Play

StepPause

Own app

Android step counter with a pause button for drives and bike rides, built after Samsung Health dropped the feature: a custom Kotlin bridge to Health Connect, Play Billing, 15 languages, 670 tests.

FlutterRiverpodDriftKotlinHealth ConnectPlay Billing
Google Play

devbot: agent platform

Own platform

Self-hosted platform where Claude Code agents take tasks from chat and from repos, with one session per channel, and close them only against a Definition of Done with tests and visual QA. ~680 chat tasks and 239 repo tasks since April 2026.

Claude CodeOpenClawAgent SkillsSubagents

More projects

  • sound_clearing

    Own platform

    AI audio and OCR platform: text-to-speech with XTTS-v2, speech-to-text with Whisper and OCR, run by 5 GPU workers behind 58 API endpoints; 611 tests.

    PythonFastAPIWhisperXTTS-v2CeleryRedisDocker

  • ksrw.pl

    Pro bono

    Moved an association's website from Weebly to a custom static generator, redesigned with Claude Design: 47 URLs, eleven 301 redirects, Playwright checks at 6 widths gating the build.

    Static site generatorClaude DesignPlaywrightPython Live site

  • teologiakatolicka.pl

    Pro bono

    Migrated a legacy theology portal to Ghost 6: 858 posts, 98.8% sentence-level match with the source.

    Ghost 6Node.jsCheerioMigration QA Live site

  • Holy See Pavilion, EXPO 2020

    Pro bono

    Visitor guide app for the Holy See Pavilion at EXPO 2020 Dubai: 5 languages including Arabic (RTL), content from WordPress over REST. Built in 2021-2022, before AI coding tools.

    FlutterBLoCWordPress REST APIi18n + RTL

  • blz-legal.pl

    Pro bono

    WordPress website for a law firm, built on a child theme of Dixon (ThemeREX) in 2020.

    WordPressPHPChild theme Live site

Experience

Senior Mobile Developer (Flutter)

LIBRUS

Dec 2019 - Present

Mobile apps of Poland's largest ed-tech: the parent and student app and the Teacher app.

  • Developed the production parent and student app (Vue 2, Cordova; iOS, Android, Huawei; 5M+ downloads on Google Play) for nearly 7 years: 1,000+ commits, 468 tickets, 28 releases prepared.
  • Built core features of the LIBRUS Teacher app in Flutter from 2021: offline-capable messaging, timetable, video training with certificates (~300 commits).
  • Brought ~20 modules of the new Flutter app to WCAG 2.2 AA (screen readers, contrast tests); earlier shipped an accessibility mode with automated axe-core tests in the Cordova app.
FlutterVue 2 + Cordova5M+ downloadsWCAG 2.2 AA
Parent app: Google Play Parent app: App Store Teacher app: Google Play Teacher app: App Store

Flutter & AI Developer

Self-employed

Feb 2023 - Present

Own products and B2B work, built with coding agents: Flutter apps, AI backends and a self-hosted agent platform.

  • Built 6 Flutter apps with coding agents in ~6 weeks (354 commits, ~2.4k tests); 3 are live on Google Play.
  • Built and run AnalizaPrawna.eu: a ReAct agent with 8 tools over 527k Polish court rulings, 139 API endpoints, ~2.8k tests.
  • Run my own infrastructure as code: 4 Linux servers with Docker Compose, Traefik, Cloudflare and a GPU for local LLMs; resolved 4 incidents with root cause, including an ISP move to CGNAT handled within a day.
FlutterLLM agentsRAGClaude Code

Junior Frontend Developer

E Net Production

Sep 2018 - Sep 2019

Front-end development, Katowice.

Skills

Mobile
Flutter (5+ years)Dartflutter_blocRiverpodgo_routerDrift (offline-first)Kotlin platform codeHealth ConnectPlay Billing & IAPi18n (15 languages, RTL)Store releasesCordova
AI & ML
LLM integrationRAG (pgvector HNSW)Self-hosted embeddings (TEI)ReAct agents & tool callingStreaming (SSE)Model failoverLLM evaluation (LLM-as-judge)Guardrails & prompt injection testsWhisper STTXTTS-v2 TTSOCR with vision modelsOllama
Agentic engineering
Claude CodeCLAUDE.md conventionsAgent SkillsSubagentsHooksMCPHeadless runsClaude Design
Web & backend
React 19TypeScriptViteTailwind CSSPWANode.js / Express (TypeScript)Python / FastAPICeleryREST APIPayU paymentsGhost themesWordPressGo (basics)Vue 2
Data & DevOps
PostgreSQL + pgvectorRedisSQLite (Drift, FTS5)FirebaseLinuxDocker ComposeTraefikNginxCloudflareGPU self-hostingPrometheus + Grafana
Testing & quality
flutter test (unit, golden, integration)VitestJestpytestPlaywrightWCAG 2.2 AAaxe-core

How I work

With AI

  • Claude Code every day since Dec 2025 (683 sessions), with my own conventions, skills and subagents.
  • A self-hosted agent pipeline takes tasks from chat and from repos and closes them only against a Definition of Done with tests and visual QA.
  • A human signs off every change: in company repos every diff is tested and reviewed by me, and about two thirds of my 2026 commits are openly labelled AI-assisted.

Working together

  • Async and in writing (Polish, English)
  • Fixed weekly capacity: 8-12 h/week
  • B2B invoice (EU VAT)
  • Happy to start with a small paid test task

Languages

Polish (native), English (professional, written)

Certificate

AI_devs 3 Agents: course on LLM apps and AI agents (Dec 2024)

Get in touch

Available for B2B work

Looking for a senior Flutter developer who also ships AI features? I take async B2B work, 8-12 hours per week. Email me a short brief.

grzegorz.hul@gmail.com LinkedIn
CV (PDF, EN) CV (PDF, PL) github.com/gregorh1 Poland (CET)