Join Us

Mobile Back-end (JS) developer

Our Story

This is Undefined is a small London-based product studio working together with startups across a range of different sectors. All ideas are different and we treat them that way. We love creating digital products with a purpose and are looking for someone to help us achieve that goal.

About the role

We're looking for a Javascript Mobile Back-end developer who is passionate about all things app & web and taking a human-first approach to digital products. In this role, you should be excited to dig deep into new platforms and grow alongside the company. You will be involved at every stage of the product development for both client & internal projects. We are looking for someone who is flexible, excited to grow alongside the company and ready to make an impact.

The ideal candidate will be self-motivated, a creative problem solver and always looking to make improvements, knowledge of Firebase & React Native with experience working on production apps is advantageous but not essential.


  • Take a user-centered approach and rapidly test and iterate
  • Comfortable working in a fast-paced environment
  • Implement new back-end feature to improve functionality & the model

About you

  • Have multiple years of professional development experience.
  • Experience integrating Api's & Auth workflows.
  • Would ideally have production experience with Firebase.
  • Bonus to have FinTech or user recommendation experience
  • Ideally would have experience in working with React Native, preferable both on iOS & Android.
  • 1-2yrs agency experience with strong UI / UX understanding and creative mindset.
  • The ability to conduct User Testing and QA testing is Bonus.
  • Able to work well remotely, both independently and with a team.
  • A positive working attitude.
  • Confident and professional.

Initially a project-based freelance opportunity, we're looking for someone that has the potential to grow with us, sharing the success of the company.

Come and join us! Please apply with your rates & availability.