Analytical Front-End Developer (Conversion Optimization & Experimentation)

Assignment type: Detachment only (ZZP/freelance not possible)
Language: English speaking
Experience: Minimum 5 years of relevant professional experience
Education: IT-related degree (e.g., Computer Science, Software Engineering)
Location: Vattenfall (

Domain: Digital Sales & Optimization
Team: IT & Digital (1300+ professionals)

We kindly but firmly ask that you do not contact us regarding tariff rates.
All proposals must be submitted in line with current market standards.
Questions regarding rates will not be answered.

Thank you for your understanding and cooperation.

About the Role

At Vattenfall, you’ll contribute to the digital transformation of one of Northern and Eastern Europe’s leading international energy companies. Together with over 1300 IT colleagues, you will play a central role in supporting and enhancing our internal and external business processes.

As an Analytical Front-End Developer, you’ll be at the forefront of data-driven experimentation and customer experience optimization. You will take ownership of the A/B testing framework and experimentation setup, collaborating closely with business, marketing, and sales stakeholders to continuously improve the online sales journey and boost customer conversion.

Key Responsibilities

As part of a dedicated Scrum team, you will:

• Develop, maintain, and optimize the A/B testing infrastructure (e.g., Optimizely, VWO, Google Optimize, or similar) to support data-driven decision-making.

• Collaborate with business, marketing, and sales teams to translate hypotheses into measurable front-end experiments.

• Implement and iterate on experiments in Angular (v9+) and related frameworks to improve customer experience and conversion rates.

• Analyze test results with data analysts to extract insights and recommend actionable improvements.

• Continuously optimize the digital sales funnel through UI/UX enhancements and performance improvements.

• Contribute to front-end standards and best practices, ensuring a consistent and scalable experimentation setup.

• Coach junior developers and share expertise in modern front-end development and testing methodologies.

• Challenge business requirements and translate them into technically feasible, measurable solutions.

Qualifications and Skills

• Bachelor’s or Master’s degree in Computer Science, Engineering, Mathematics, or a related technical field.

• Proven experience with Angular (v9+), TypeScript, SCSS, HTML5, and RxJS.

• Hands-on experience with A/B testing and experimentation tools (e.g., Optimizely, VWO, Google Optimize, or custom setups).

• Familiarity with analytics platforms such as Google Analytics or Adobe Analytics.

• Strong understanding of Conversion Rate Optimization (CRO) principles.

• Experience with CI/CD pipelines (Azure DevOps) and Git/Gitflow.

• Experience with unit testing (Jest) and UI testing (Cypress).

• Understanding of Azure Cloud and REST-based architectures.

• Fluent in Dutch and English, both written and spoken.

• Analytical mindset with strong communication skills and the ability to collaborate effectively with non-technical stakeholders.

• Structured, proactive, and passionate about continuous improvement and measurable impact.