Haydar Duman

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

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

Engine remapping tools, international product · Luxembourg

• 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.

Specialist e-commerce · Waterloo

• 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.

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.

Web agency · Liège

• Delivered around a dozen complex PrestaShop stores, from theme creation to custom modules.

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).

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).

Official mobile app of Spa airfield (EBSP): airfield information and pilot services.

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.

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.

github.com/dumanhaydar/xrhud

Native iOS app built on top of Home Assistant, with automations and ESP32/ESPHome sensor integration.

Backend for generating and managing Apple Wallet / Google Wallet cards: pass signing, push updates, lifecycle and revocation.