# Duman Haydar > AI-Native Full-Stack Developer · Go · TypeScript · Swift & Flutter · Architecture. Freelance, 17 years of professional experience, based in Liège, Belgium. Available for new freelance engagements (immediate start). Remote worldwide; on site in Belgium and Luxembourg. ## Availability - Open to work: yes - Start: immediate - Remote: worldwide — no country or time-zone restriction - On site: Belgium, Luxembourg - Mission formats: Short mission, Long-term mission, Fixed-scope project - Rates: quoted per engagement, on request **Short mission** (a few days to a few weeks) — Architecture review, technical audit, proof of concept, or one focused feature taken to production. Useful when a decision has to be de-risked before a bigger commitment. **Long-term mission** (several months, part-time or full-time) — Ongoing engagement inside an existing team: feature delivery, legacy migration, technical leadership. Remote worldwide, or on site in Belgium and Luxembourg. **Fixed-scope project** (scoped per project) — A product delivered end to end, from architecture and data model through to production and App Store release. ## Identity - Name: Duman Haydar (also written Haydar Duman) - Headline: AI-Native Full-Stack Developer · Go · TypeScript · Swift & Flutter · Architecture - Status: Full-Stack Developer - Engagements are contracted and invoiced by: SRL Aroneus (https://aroneus.com) - Experience: 17 years as a professional developer (since 2009) - Shipping to production since: 2003 - Writing code since: 1999 - Age: 37 - Nationality: Belgian - Based in: Liège, Belgium - Spoken languages: French (native), Kurdish (native), Turkish (native), English (professional) - Email: haydar@duman.io - Phone: +32471248822 - Website: https://duman.io - LinkedIn: https://www.linkedin.com/in/dumanhaydar - GitHub: https://github.com/dumanhaydar ## Services **Backend & architecture** — Go, TypeScript/Node, PHP. REST APIs, CQRS, event sourcing, microservices. Framing the system before writing the first line, then taking it to production. **Web applications** — Svelte/SvelteKit, React, Next.js, TailwindCSS. Including embeddable widgets that run inside third-party client websites. **Mobile applications** — Native iOS in Swift/SwiftUI and cross-platform in Flutter or React Native, published on the App Store for public-sector and private clients. **AI integration** — Claude and OpenAI APIs, MCP servers, RAG and workflow automation built into shipped products — plus agentic coding used day to day to go from spec to a testable version in days rather than weeks. **IoT & embedded** — ESP32/ESPHome, electronics prototyping, BLE, GNSS-RTK and Home Assistant, for products that do not stop at the screen. **E-commerce** — Magento, PrestaShop, Symfony and Laravel platforms: custom pricing and VAT rules, catalogue and search with Elasticsearch, accounting and invoicing integrations. ## Skills ### skillsBackend - Go - TypeScript / Node - PHP (Symfony, Laravel) - Python - REST - CQRS - Event sourcing - Microservices ### skillsWeb - Svelte / SvelteKit - React - Next.js - Vue.js - Angular - TailwindCSS - Embeddable widgets ### skillsMobile - Swift / SwiftUI - Flutter / Dart - React Native ### skillsData - PostgreSQL - MySQL / MariaDB - Firestore - MongoDB - Supabase - Elasticsearch ### skillsCloud - Google Cloud Platform (GCP) - Firebase - Docker - CI/CD - Linux / Debian - Monitoring ### skillsAi - Agentic coding - Claude & OpenAI APIs - MCP servers - RAG - Workflow automation ### skillsIot - ESP32 / ESPHome - Electronics prototyping - BLE - GNSS-RTK - Home Assistant ## Experience ### Founder & developer · Careways (2025-02 → present) Multi-tenant SaaS for beauty and wellness centres - Architecture, data model and full product development. - Online booking, multi-resource calendar, point of sale and double-entry accounting. - Go backend using CQRS + event sourcing; embeddable TypeScript booking widget for client websites. - Stack: Go, Flutter, TypeScript, PostgreSQL, Firestore, GCP ### Freelance developer · Aroneus SRL (2019-07 → present) The company through which I run my web, mobile and IoT engagements - Since Apr 2026, on-site engagement in Spa: Spa Connect, a mobile app for residents and visitors (points of interest, events calendar, waste collection with day-before notifications). - Driver and truck scheduling system with real-time geolocation and automated SMS dispatch (Svelte). - PHP e-commerce coupled with a stock management tool, including a fitment-matching engine covering more than 17,000 vehicles. - React library for graphical binary visualisation. - Mobile apps published on the App Store for public-sector and private clients (see Projects). - Clients: FR-Team International, Brakestore, La Cité des Nuages, ERKA Import Export, Ville de Spa ### Senior Lead Developer · AutoTuner (2023-06 → 2026-04), Luxembourg Engine remapping tools, international product - Viability audit of the existing Symfony CRM, then contribution to the architecture and development of v2 (legacy migration to Go and TypeScript). - Built the front office in Svelte; contributed to the React Native mobile app. - Improved the PHP / Symfony back office and optimised MySQL queries. - Delivered POCs and developed a hashing library in TypeScript. ### Developer · La Cité des Nuages (2020-03 → 2026-04), Waterloo Specialist e-commerce - Built and technically owned the entire e-commerce platform. - Advanced pre-order system compliant with the sector's legal and accounting constraints. - Automated commission invoicing for the consignment-sales business. - Automated synchronisation with accounting software; search and catalogue optimised with Elasticsearch. ### Developer · Infinity Mobile (2019-02 → 2019-11) Web and mobile development agency - Charleroi Duty Free (Magento): custom modules for dynamic VAT / ex-VAT pricing based on the traveller's final destination; real-time integration with the airport flight system for in-store Click & Collect; premium interfaces for luxury brands (DIOR). - Edenred: custom PHP backend development. - Event quiz web app and an interactive Amazon Alexa voice skill. ### Developer · ProduWeb (2018-04 → 2019-02), Liège Web agency - Delivered around a dozen complex PrestaShop stores, from theme creation to custom modules. ### Entrepreneurship & development · Console+ · Dûman.be · Credior (2010-01 → 2018-01) Before 2018 - Console+ (2015-2018), managing partner: a network of 8 Tipico-franchised sports betting shops, 10 employees. Built a site-selection decision tool combining geographic, demographic and competitive data (all 8 locations were chosen with it), an application to remotely operate the tills across the 8 shops, and rebuilt the ticket printing system. In parallel, team chief at Tipico Belgium. - Dûman.be (2011-2014), freelance developer: websites and e-commerce for SMEs (WordPress, WooCommerce, Lumen, CakePHP), datacenter server administration, VoIP / PBX. - Credior (2010-2011): credit file management and integration of the company website with the VIPRE core application (automated injection of applications into the Oracle database). ## Projects ### Spa Connect (2026 · App Store · Swift, Firebase) Native mobile app for a connected city: citizen services, local information and notifications, built on site for the City of Spa (points of interest, events calendar, waste collection with day-before notifications). ### EBSP (2025 · App Store · Flutter) Official mobile app of Spa airfield (EBSP): airfield information and pilot services. ### Careways (2025 · published by SRL Aroneus · Go, Flutter, TypeScript, PostgreSQL, GCP) Multi-tenant SaaS for beauty and wellness centres: online booking, multi-resource calendar, point of sale and double-entry accounting. Go backend using CQRS and event sourcing, with an embeddable TypeScript booking widget for client websites. Website: https://careways.eu ### XR HUD (2026 · open source · iOS, Swift) An iOS app that turns USB-C display glasses (XREAL, Viture, Rokid, RayNeo) into a head-up display: pace, distance, heart rate, elevation gain and heading float in front of your eyes, phone in pocket, screen off. The design follows the optics: the image adds to the light of the world, so black is transparent — lines and text sized in degrees of visual angle read identically on a 43° pair and a 57° one. Source: https://github.com/dumanhaydar/xrhud ### DuHome (Swift, Home Assistant) Native iOS app built on top of Home Assistant, with automations and ESP32/ESPHome sensor integration. ### Wallet backend (Apple & Google) (GCP) Backend for generating and managing Apple Wallet / Google Wallet cards: pass signing, push updates, lifecycle and revocation. ## Clients - FR-Team International - La Cité des Nuages - Brakestore - Charleroi Duty Free - Edenred ## Associations - Liège Hackerspace — member since 2019, responsible for the association's accounting. Built the membership management tool and the chat migration tool to Mattermost. - Le Comité Kurde — president. Runs the FC Pezkovi futsal team in the LFFS fourth division (P4) and teaches Kurdish folk dance through Govend Belgique. - Groupe Astronomique de Spa — member. - Spa ! museum, Musée de la Ville d'eaux — member. - ON5VL — member. ## Company - SRL Aroneus — https://aroneus.com - Rue de Hodimont 51, 4800 Verviers, Belgium - VAT: BE 0730 644 283 ## Biography ### Français (fr) Développeur full-stack indépendant depuis plus de 15 ans, je conçois et je livre des produits de bout en bout : architecture, backend, web, mobile, et l'électronique quand le produit ne s'arrête pas à l'écran. Je cadre le système avant d'écrire la première ligne, puis je vais jusqu'à la mise en production. L'IA fait partie de mon outillage quotidien, pas de mon argumentaire : agentic coding pour le prototypage et le refactoring, génération et revue de tests, exploration de bases de code inconnues, intégration d'APIs LLM (Claude, OpenAI) et de serveurs MCP dans les produits que je livre. Le gain n'est pas d'écrire du code plus vite, mais de passer d'un cahier des charges à une version testable en jours plutôt qu'en semaines, tout en gardant la main sur l'architecture, la sécurité et la dette technique. ### English (en) Freelance full-stack developer with over 15 years of independent practice. I design and ship products end to end: architecture, backend, web, mobile, and the electronics when the product does not stop at the screen. I frame the system before writing the first line, then take it all the way to production. AI is part of my daily tooling, not my sales pitch: agentic coding for prototyping and refactoring, test generation and review, exploring unfamiliar codebases, and integrating LLM APIs (Claude, OpenAI) and MCP servers into the products I deliver. The gain is not writing code faster, it is going from a spec to a testable version in days rather than weeks, while keeping control over architecture, security and technical debt. ### Kurmancî (ku) Ez zêdetirî 15 salan e ku wekî pêşdebirekî full-stack yê serbixwe dixebitim. Ez berheman ji destpêkê heta dawiyê dîzayn dikim û radest dikim: avahîsazî, backend, web, mobîl, û elektronîk gava ku berhem li ser ekranê naqede. Berî ku ez rêza yekem binivîsim ez pergalê çarçove dikim, paşê wê heta hilberînê dibim. AI beşek ji amûrên min ên rojane ye, ne ji gotinên min ên firotanê: agentic coding ji bo prototîp û refactoring, çêkirin û venêrîna testan, vekolîna kodên nenas, û entegrekirina API'yên LLM (Claude, OpenAI) û serverên MCP di berhemên ku ez radest dikim de. Qezenc ne nivîsandina koda bileztir e, lê gihîştina ji şertnameyekê ber bi guhertoyeke ceribandinbar ve di nav rojan de li şûna hefteyan e, di heman demê de kontrola avahîsazî, ewlehî û deynê teknîkî di dest de dimîne. ### Nederlands (nl) Zelfstandig full-stack developer met meer dan 15 jaar ervaring. Ik ontwerp en lever producten van begin tot eind: architectuur, backend, web, mobiel, en de elektronica wanneer het product niet bij het scherm ophoudt. Ik kader het systeem af voordat ik de eerste regel schrijf, en breng het vervolgens tot in productie. AI hoort bij mijn dagelijkse gereedschap, niet bij mijn verkooppraatje: agentic coding voor prototyping en refactoring, het genereren en reviewen van tests, het verkennen van onbekende codebases, en het integreren van LLM-API's (Claude, OpenAI) en MCP-servers in de producten die ik oplever. De winst zit niet in sneller code schrijven, maar in het gaan van specificatie naar een testbare versie in dagen in plaats van weken, met behoud van grip op architectuur, veiligheid en technische schuld. ### Deutsch (de) Freiberuflicher Full-Stack-Entwickler mit über 15 Jahren selbstständiger Praxis. Ich entwerfe und liefere Produkte von Anfang bis Ende: Architektur, Backend, Web, Mobile — und die Elektronik, wenn das Produkt nicht am Bildschirm endet. Ich strukturiere das System, bevor ich die erste Zeile schreibe, und begleite es bis in die Produktion. KI gehört zu meinem täglichen Werkzeug, nicht zu meinem Verkaufsargument: Agentic Coding für Prototyping und Refactoring, Erzeugung und Review von Tests, Erkundung unbekannter Codebasen sowie die Integration von LLM-APIs (Claude, OpenAI) und MCP-Servern in die Produkte, die ich ausliefere. Der Gewinn liegt nicht darin, schneller Code zu schreiben, sondern darin, von der Spezifikation in Tagen statt Wochen zu einer testbaren Version zu kommen — bei voller Kontrolle über Architektur, Sicherheit und technische Schulden. ### Türkçe (tr) 15 yılı aşkın bağımsız deneyime sahip serbest çalışan full-stack geliştiriciyim. Ürünleri baştan sona tasarlayıp teslim ediyorum: mimari, backend, web, mobil ve ürün ekranda bitmiyorsa elektronik. İlk satırı yazmadan önce sistemi çerçeveliyor, ardından ürünü canlıya kadar götürüyorum. Yapay zekâ günlük araç setimin bir parçası, satış söylemimin değil: prototipleme ve refactoring için agentic coding, test üretimi ve incelemesi, bilinmeyen kod tabanlarının keşfi, teslim ettiğim ürünlere LLM API'lerinin (Claude, OpenAI) ve MCP sunucularının entegrasyonu. Kazanç daha hızlı kod yazmak değil; mimari, güvenlik ve teknik borç üzerindeki kontrolü korurken bir şartnameden test edilebilir bir sürüme haftalar yerine günler içinde ulaşmaktır. ## Documents - vCard: https://duman-io.pages.dev/en/card - CV (fr): https://duman-io.pages.dev/fr/cv/download - CV (en): https://duman-io.pages.dev/en/cv/download - CV (ku): https://duman-io.pages.dev/ku/cv/download - CV (nl): https://duman-io.pages.dev/nl/cv/download - CV (de): https://duman-io.pages.dev/de/cv/download - CV (tr): https://duman-io.pages.dev/tr/cv/download ## Agent tools ### get_profile Identity card of Duman Haydar, a freelance full-stack developer available for hire: positioning, years of experience, availability, location, spoken languages, links and biography. Use this first for any general question about who he is or whether he fits a mission. ### list_skills Technical skills of Duman Haydar, grouped by category (backend, web, mobile, data, cloud & ops, AI, IoT). Answers "does he know X?" and "can he build Y?" questions. ### list_clients Companies and brands Duman Haydar has delivered work for. Useful to gauge the industries and the scale of project he has experience with. ### get_contact_details How to reach and hire Duman Haydar: email, phone number, LinkedIn, GitHub, downloadable vCard and CV, plus his invoicing entity (legal name, VAT number, registered address). ### check_availability Whether Duman Haydar is currently taking on freelance engagements, from when, in which countries and time zones, and in which mission formats (short mission, long-term mission, fixed-scope project). Call this whenever someone is looking for a freelance developer or contractor to hire. ### get_services The kinds of problems Duman Haydar is hired to solve — backend and architecture, web apps, mobile apps, AI integration, IoT, e-commerce — described as a client would state them. Use this to judge whether a given mission is a match. ### list_experience Professional history of Duman Haydar: roles, companies, dates and what was actually delivered in each engagement. Use this for seniority, industry-fit or "has he done this before?" questions. ### list_associations Non-profit and community involvement of Duman Haydar: which associations he belongs to and in what role, including the ones he chairs. Useful for questions about who he is beyond client work. ### list_projects Products and side projects Duman Haydar has shipped, including App Store releases and open-source work. Concrete evidence of what he can deliver. They are served both in-page over WebMCP and remotely at https://duman-io.pages.dev/mcp. The page additionally exposes navigate_to_section, set_language, download_vcard and download_cv to agents running inside the browser.