Senior Software Engineer (Backend)



We believe that faster, more diverse clinical trials help extend the human health span and provide a greater return on investment.

We strive to improve the clinical trial experience for patients, sites and sponsors, using technology to accelerate every step of the clinical trial journey.

Our modular clinical trial platform enables the capture and re-use of research data from anywhere, anytime and helps optimize each activity in the clinical trial journey by reducing human effort with technology. From recruitment to monitoring, we help make it easier to design and deploy trials, enroll and engage patients, collect data and analyze results.

Next to being very purpose-driven, we are proud of our caring company culture. We follow our values diligently and take the well-being of each Castorian seriously. Sounds like something for you? Read on !


As a Senior Software Engineer (Backend), you’ll be joining our CDMS product team. Here you’ll work on expanding our flagship product to implement exciting new features that will help take our platform to the next level. Your main responsibility will be architecting scalable and maintainable solutions that adhere to industry best practices.

Concurrently, you will help maintain the application stability and performance levels to ensure customer satisfaction.

As part of your role you will also take part in our on-call rotation.


  • You have a computer science background and 5+ years of work experience
  • You are passionate about software architecture challenges and like to both design and implement new solutions
  • You have experience building high traffic, scalable web-based applications (SaaS)
  • You like to work together with your team members and have great communication skills


  • Practical experience with modern PHP programming, design patterns, OOP, and automated tests
  • Practical knowledge in software architecture patterns with focus on event-based approaches
  • A creative mindset with the ability to help solve challenging domain problems
  • Solid understanding of software development lifecycle and agile methodologies
  • Attention to details and high quality work

It would be good if you had: 

  • Experience within life sciences, healthtech or e-clinical products.
  • Experience with cloud-based message-brokers
  • Experience with Event Sourcing or CQRS architectural patterns
  • Proficiency in modern PHP frameworks such as Symfony, or Laravel

Please note that we are open to hire from different European countries. However, we are unable to accept applications from France, Germany, Spain, Bulgaria, Sweden and Switzerland

How Castor takes care of you

At Castor we truly live and breathe one of our core values, believing we can achieve anything with a healthy and happy team. Our benefits reflect this:

  • Guaranteed ‘happy holidays’ bonus  
  • Employee Stock Option Plan 
  • Learning & Development Budget to support your growth
  • Unlimited annual leave 
  • A fully remote role, with support for your home office set-up
  • flexible working schedule: nobody is tracking your time except you, we focus on output and delivery
  • A great work-life balance
  • Quarterly downtime weeks, well-being workshops, sleeping courses, access to OpenUp, virtual company events and celebrations


We are a remote-first company. At Castor,  we value flexibility and believe that the best talents can work anywhere in the world. From flexibility improvements to productivity growth, we want to make sure you are happy, healthy, and productive while working from home.

Every Castorian counts. We celebrate you for who you are. We build products to make clinical research accessible to the world and a company where everyone, anywhere, is welcome. It does not matter where you are from, where you are based, or what your gender, age, or sexual orientation is.

Our remote-first setup is for your family, your work-life balance, your mental health, and your right to be your most authentic self. You are celebrated for who you are, for all the differences and quirks that define you. We want your unique voice to be heard and succeed together as a happy and healthy team!

Castor continues to grow as an Equal Opportunities Employer. We strongly encourage applications from women, people of color, and people from the LGBTQ(+) community. Please feel free to share the pronouns you use (for example she/her/hers, he/her/his, they/them/theirs, etc.).


Our Interview Process


Fill out a short application on our careers website.

Telephone Call
Telephone Call

If your application is successful, we’ll invite you to an intitial call with a member of our talent team.

Manager interview
Manager interview

Great news! You’re invited to meet the hiring team.

Interview Day
Interview Day

Now we’ve got even better acquanted, we’d like to invite you to a final stage interview day.


Congratulations! We’re making you a formal offer to join as our next Castorian!

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