ElasticSearch / .NET Developer, permanent opportunity, Utrecht area (remote-first)

CISO-Office is offering a great opportunity for a skilled ElasticSearch Specialist with development experience in .NET and React. You will join a diverse, international team building a software product that supports emergency services, healthcare, and defence organisations. This means your work will have direct impact in mission-critical environments where security, performance, and reliability are essential.

In this role, you will be responsible for designing, optimising and extending search infrastructure, while also integrating it into customer-facing applications. You’ll work closely with developers and AI specialists to deliver scalable, secure, and future-ready search functionality.

Responsibilities

• Design and optimise ElasticSearch infrastructure for speed, accuracy, and scalability

• Improve search relevance and performance for mission-critical use cases

• Build advanced features such as autocomplete, facets, and filtering

• Document configuration and integration for smooth handover to clients

• Collaborate with .NET and React developers to integrate search capabilities into applications

• Work with LLM specialists to support AI-driven search functionality

Profile

• Deep knowledge of ElasticSearch (or similar search technologies)

• Experience with query optimisation and indexing strategies

• Strong debugging and tuning skills

• Hands-on experience integrating search in .NET back-end and React front-end environments

• Fluent English (team language); Dutch is a plus but not required

What we offer
Join a growing company where your work supports organisations that safeguard lives and security. While the office is based near Utrecht, the team mostly works remote-first, with occasional office meetups by agreement.

• Competitive salary

• Hybrid/remote-first working model

• Flexible hours

• Opportunity to work on advanced search and AI-driven solutions with real-world impact in security-sensitive industries

If you would like to find out more about this opportunity and the company, please get in touch.