— Senior Android App Developer

Wiebe Geertsma, BSc.

Bridging Mobile & AI Innovation.

Drachten, The Netherlands

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12+

Years of experience

Production apps shipped

Languages spoken

01 Career

Experience

Twelve years of building performant, reactive Android applications — from greenfield apps to modern banking platforms. Tap any role to expand the details.

International mobile-first agency · 500–1,000 employees
Implement new features into banking apps and update them to modern standards.
Maintain the apps to keep them running smoothly.
Alongside the client work, built hands-on expertise in AI orchestration — directing AI agents to migrate a banking app's legacy UI from XML/Fragments to Jetpack Compose.
Configured agents across different effort levels and models, with a focus on token efficiency.
Started out with GitHub Copilot, but now works almost exclusively — about 99% of the time — with Anthropic's Claude Code.
Independent project — hand-built after leaving Booqable, now growing it into a real product.
Architected a cross-platform app from scratch — Kotlin Multiplatform and Compose Multiplatform for Android and iOS, sharing one domain layer, plus a Next.js web client.
Built a single Ktor backend on DigitalOcean App Platform serving all three clients over one REST API.
Shipped an AI-powered feature that estimates meal macros from a plain-language description, removing the biggest friction point in food logging.
Kept core features — barcode scanning, food catalog, recipes, and shopping lists — free and ad-free by design.
Handles payments via Stripe for an optional Supporter membership tier.
About the company
GreaseFit is a free, ad-free nutrition and fitness tracking app I've been building independently under my own company, Greasy Apps, since 2025, after leaving Booqable. It's cross-platform from the ground up — Kotlin Multiplatform and Compose Multiplatform power the Android and iOS apps from a single shared codebase, alongside a Next.js web app, all backed by one Ktor server. The standout feature is AI-powered meal estimation: describe what you ate in plain language and get a macro breakdown back, instead of hunting through a food database. It's built to professional security standards — GDPR compliant, with data encrypted at rest and in transit, hosted in Amsterdam.
SnappCar — a peer-to-peer car-sharing platform based in Utrecht.
Android development work during a short-term engagement.
Rental software company (Salad Days B.V.) · 30–50 employees
Architected a performant, reactive, and layered application using the Repository Pattern and Dependency Injection (Dagger/Hilt).
Implemented a domain layer for shared business logic with the iOS app using Kotlin Multiplatform (KMP).
Established CI/CD pipelines for automatic deployment to app testers and the Google Play Store.
Built the UI layer with state holders, enhancing responsiveness and maintainability.
Integrated push notifications with instant reply functionality to boost user engagement.
Conducted Unit Testing and UI Testing to ensure app reliability and performance.
Optimized the app using R8 for code shrinking and obfuscation.
Managed a SQLite database for local data storage.
Wrote complex SQL queries to improve the performance of data-heavy screens.
Fetched data from a JSON:API spec API.
About the company
Booqable, operated by Salad Days B.V., is a rental-management software company based in Leeuwarden, the Netherlands. It grew out of software originally built in 2009 for Budgetcam, a Dutch camera-rental firm, and launched as a dedicated product in 2014. Its cloud platform brings inventory management, an online booking store, and integrated payments together in one place, serving thousands of rental businesses worldwide. Booqable is built by a remote-first team of around 37 people spread across sixteen countries.
After the Exact acquisition — leading the mobile team through the rebrand from Bouw7 to Exact Construction.
Grew from intern to leading a mobile team of 6 as the app and company scaled.
Shepherded the app through the rebrand from Bouw7 to Exact Bouw — published as 'Exact Construction'.
Managed app releases across Android and iOS.
Aligned the mobile roadmap with Exact Online integration following the acquisition.
About the company
In June 2019 Bouw7 was acquired by Exact for an undisclosed sum and rebranded Exact Bouw — now marketed as Exact Construction — integrating with Exact Online and targeting the roughly 3,700 construction firms already using Exact for their bookkeeping.
Construction cloud-software startup · building out the mobile apps as the product scaled.
Migrated the app from Java to Kotlin, introducing a Repository pattern and Dependency Injection (Dagger/Hilt).
Converted the iOS app's Objective-C codebase to Swift — effectively rewriting the iOS app alongside the Android work.
Designed a performant, reactive app, optimized for large and complex datasets.
Managed the SQL database using Realm and fetched data from a JSON API.
Integrated push notifications.
Established CI/CD pipelines for automatic deployment to app testers and the Google Play Store.
About the company
Bouw7 was founded in 2015 in Dokkum, the Netherlands, by Sander Jongsma, with a mission to modernize traditional construction-industry administration through user-friendly, cost-effective cloud software — covering project management, planning, time tracking, material processing, and invoicing for small and mid-sized construction businesses. Backed by investors NOM and Rockstart (through its Web & Mobile accelerator program), it grew into one of the fastest growing startups in Friesland, reaching around 30 employees.
Jun 2019Bouw7 acquired by Exact Group
Bouw7Sep 2015 — Jan 2017
Android Developer Intern
Built the company's Android app from scratch during my internship — including offline support for construction sites with no connectivity.
Wetlantec IoT2016 — 2017
Grasslands2015
Renegade X2014 — 2017
Polem B.V.2010
Production worker (assembly)
Silo and auger construction — assembly and finishing of four silos.
Gamma2010
Sales assistant
General sales assistant at the DIY store.
Biddle B.V.2009
Intern → temporary employee
Developed an air-flow meter that measures the convection of air across a surface. Kept on temporarily after the internship to finish the project given its scope; drafted in Solid Edge and AutoCAD.
Norma IMS2008 · 20 weeks
Intern (metalworking)
Metalworking firm that develops stamping plates within Philips for the cutter heads of electric shavers. Worked with wire- and sinker-EDM machines.
R&B Hameko B.V.2007 · 20 weeks
Intern / production worker
Stainless-steel interior products — production of stairs, tables and chairs. Basic metalworking: welding, drilling, sawing and measuring.
Relco Wet & Dry B.V.2006 · 20 weeks
Intern (mechanical engineering)
Complete process installations in stainless steel — drying towers and vibrating beds. Adjusted AutoCAD drawings to standards and assisted the project leader with gathering product information and writing manuals.
Dunlop Conveyor Belting2006 — 2008 · summers
Technical-service assistant (summer work)
Summer work with the in-house technical service, assisting the electrician with mechanical and electrical maintenance of the machines used to produce conveyor belts.
Education
HBO Bachelor Communication & Multimedia Design
NHL Hogeschool
2012 — 2017
NLQF 6 / EQF 6
Hbo Werktuigbouwkunde (unfinished)
NHL Hogeschool
2011
Mbo Werktuigbouwkunde
Regionaal Opleidingen Centrum Friese Poort
2005 — 2010
NLQF 4 / EQF 4
Niveau 4 · Crebo 10054 · the highest level attainable at this qualification tier.