Freelancer profile translated to English.
Back to original languageAbout Arjan
Senior backend developer with 20 years of experience in PHP, Symfony, and Laravel. I build and optimize scalable backend systems, REST APIs, and complex integrations between applications, with PostgreSQL and MySQL as a trusted foundation.
My specialization lies in system and ERP integrations. I have built integrations with Twinfield, Exact Online, and AFAS, among others, and know what it takes to ensure reliable data flow between systems. Additionally, I utilize Python and modern AI tooling (function calling, n8n) to automate processes and reduce manual work.
As a (lead) backend developer, I combine in-depth technical knowledge with the overview to manage teams and projects. I have worked in the insurance, e-commerce, and media sectors, among others.
Where I make a difference: stable, maintainable code, faster systems, and integrations that eliminate errors and manual labor. Available for assignments in and around Amsterdam (up to 50 km) and remote.
Dutch
Native or bilingual
English
Fluent
Can work on-site
Amsterdam (up to 50km)
Experience
- InsharedFreelance Backend DeveloperBANKING AND INSURANCEJune 2020 - Today (6 years and 2 months)Leusden, Netherlands• • Performance improvement. Due to technical debt multiple queries (some of which were over 700 lines of SQL) took anywhere from 3-30 minutes. I've been able to refactor those queries, resulting in an execution time of less than a minute.• • Create a machine learning model to detect fraud.• • Added automatic payment of applicable Home and Household claims, so they don't have to be processed manually by employees• • Develop a new animal insurance product, with automatic processing and payment of claims.• • Connected / implemented several API's:◦ o HCAI (Canadian platform that handles health insurance claims)◦ o CompanyInfo (provides an UBO check, which is used to check if persons and companies which are recipients of a payment are not members of a criminal organisation or on a terrorism list)◦ o HIS: A German organisation where insurers need to report claims and claimants for InShared Germany.
- NHMEDIA (NH NIEUWS / AT5)Senior DeveloperPRESS AND MEDIAJanuary 2018 - December 2018 (11 months)Amsterdam, NetherlandsBackend developer for the digital platforms of AT5 and NH Nieuws. In just over a year and a half, worked on API development, system integration, and a large-scale cloud migration:
- Consolidated fragmented legacy code from multiple servers into one central API with the same functionality, at a fraction of the cost and maintenance.
- Developed and maintained Video Mover: a tool that distributes videos processed by the render farm to the streaming partner, the CMS, and Amazon S3, and provides the CMS with metadata via the API.
- Rewrote this tool from Phalcon to Symfony and Vue.js, for more maintainable code on a more widely supported framework.
- Developed and maintained the feed API for the AT5 and NH Nieuws apps, including XML generation for the NH Nieuws website via Regiogrid.
- Guided the technical migration to a greenfield AWS environment with three involved parties (Nordcloud, CMS provider Angrybytes, and internal), including CI/CD and microservices — responsible for correctly specifying the environment for our own tools and those of the CMS provider.
- Linked the internal API to various external APIs: weather, ANWB traffic information, and the streaming partner.
- Arjan van der Hulst WebsolutionsOwner / FreelancerDIGITAL AND ITJanuary 2018 - Today (8 years and 7 months)Hoofddorp, Netherlands
Voice-driven time tracking system
Voice-controlled time tracking for the construction and installation sector. Employees speak their hours via WhatsApp; AI (Whisper + Claude) processes and registers them in Excel. Result: less administration, fewer errors, hours immediately available for invoicing.Stack: Python, Flask, openpyxl, n8n, Railway, Claude API.Custom quote and sales tool with AFAS integration
Custom quote application with integrated sales dashboard for an installation and electrical engineering company, fully integrated with AFAS Profit.Quote module:- User management with roles and approval flow
- Building quotes from reusable "quote products" (sets of AFAS articles) with adjustable quantities
- Categorization by AFAS cost types and custom categories (CCTV, lighting, etc.)
- Real-time retrieval of complexes, contacts, and articles from AFAS via function calling
- Version control with structured quote ID
- Writing approved quotes as projects in AFAS
- PDF generation and LLM integration (Claude) for text processing and product lookup
Sales dashboard:- Net quote value per month and annual overview
- Number of issued, outstanding, and won quotes (filterable by advisor)
- Conversion rate and top 10 customers
- Weighted pipeline forecast
- Average order value and quote-to-order lead time
Stack: PHP, Laravel, SQL, AFAS Profit API, Claude API, JavaScript.Quote follow-up & AI integration (n8n)
Automation of quote follow-up via n8n, linked to an existing AFAS quote tool. Includes AI-driven product lookup via function calling on an AFAS backend search endpoint. Result: faster lead times and higher conversion.Excel microservice for n8n
Python Flask microservice (openpyxl, Railway) that allows n8n to write directly to Excel. Open source on GitHub. Building block for automations where Excel is the final format.
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Education
- HAVOHerbert Vissers College2002HAVO
- MBO ICT LevelROC2006MBO ICT Niveau