Back-End Developer Johan Sports

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We are looking for an engineer experienced in working with server-side technologies to help our team develop innovative solutions and support the existing system.

At JOHAN Sports we guide sports teams to achieve higher performances and reduce injuries by combining Data Science and Sport Science. Data is collected from wearable devices and/or web forms (e.g. GPS/heart-rate trackers, WebApp, mobile application).

Most clubs can’t afford or don’t have the know-how to work with a Performance Monitoring System. We focus on making such technologies affordable and easy to use for sports teams on all levels!

Recently acquired by Demcon, we are a small but ambitious group of people which still operates independently so you can expect a start-up environment while being backed by a well-rounded company. We are looking to expand our technical team and accelerate the development of the JOHAN Sports ecosystem.

As part of the back-end team, you will help with the maintenance and development of our backend code and infrastructure. Together, we will ensure that data from our various interfaces (user-facing and downstream), flows safely and efficiently throughout our system.

You will collaborate with team members and parties (business, operations, front-end, sports scientist and hardware developer) to discuss promising ideas and features, assess their technical feasibility and translate them into solutions. You will most often own the feature/project you work on from ideation to production.

Note that we do not expect you to have extensive knowledge in all points raised below but you expect to build experience in those fields over time if you join the team. We want you to work on what excites you but being part of a small team, some polyvalence is greatly appreciated.

About Demcon

Demcon johan sports is een ontwikkelaar van GPS-volgsystemen voor het bewaken van de gezondheid en het verbeteren van de prestaties van sportteams. Each one of our companies differentiates itself in its own domain with unique expertise and skills. This way they help customers improve their performance and achieve more. On the basis of their passion for technology our companies are able to combine forces. By sharing knowledge and working together we increase our social impact. Demcon johan sports is a developer of GPS tracking systems for monitoring the health and improving the performance of sports teams.

What are you going to do?

Your routine work could consist in:

contributing to project specifications and assessing project impact in terms of resources and time;

designing back-end code and infrastructure solutions;

spotting candidate technologies to support our development;

when necessary, setting up contracts between developer parties (e.g API, Doc);

Implement the solutions. Write code Mainly in Elixir, sometimes in python;

A minimum of security and observability (e.g monitoring) must be considered in the solutions;

Ensuring tests, documentation and good practices via code reviews;

Improving/Supporting preexisting code.

Some example projects you could be working on:

Various user-facing APIs (WEB application, live monitoring application, Mobile application etc…).

Various downstream services inter-communication.

External API (e.g data synchronisation with third-party companies).

Data-pipeline: Ingestion/transformation of objective/subjective data collected from players’ wearables or web/mobile forms.

Transformation of objective/subjective player data into actionable human advice.

Help data scientists build ML models providing access to the data they need and integrating their models.

Reporting engine from aggregated data destined to team managers (e.g CSV/XLSX/PDF).

Back-office features to support operations (e.g firmware releases, hardware management).

The modernisation of our system migrating key features from our legacy system.

While limited infrastructure knowledge is required to get started on the job, let us give you an idea of our back-end stack in which you will operate:

The entire infrastructure: applications, storage and domain routing is hosted on AWS. For our storage layer, we use S3, RDS instances (MySql) and DynamoDB. Our computing layer is either based on dockerized applications hosted on EC2 instances (monitored under ECS Custers) or AWS lambdas for ephemeral computing.

Services reside under VPCs and resilient inter-services communication is generally ensured via a combination of queues and event notifications. Most of our infrastructure is maintained and versioned via terraform or the serverless framework. We provision our servers using Ansible and the code release cycle is done via CI/CD.

You could get involved in working/learning Infrastructure development:

Setting up new infra resources to support new projects

Setting up appropriate alarms and logging for our various resources

Cost optimisation (e.g Resources lifecycle purging/archiving stale or less-frequently used objects)

Automated or manual monitoring/investigation of our system

Maintenance of our infrastructure as code

Working on continuous integration/deployment workflow

Find a good cost/efficiency compromise

What do you bring to the table?


2+ years of production experience In Elixir or other programming languages

5+ years of overall software engineering experience

Experience building web applications with Phoenix or similar web framework (e.g ruby/rails)

Experience designing APIs

Willing to learn Elixir/Phoenix and work with it on a daily basis

Experience working with relational databases

Experience working in an Agile environment

Excellent communication and collaboration skills

Nice To Have:

Good Knowledge of Elixir/Phoenix, python/Django

Experience in dev operations in a cloud-based infrastructure like AWS

Experience with Docker and containerized environments

Experience with Serverless technologies

Experience with message queues, data pipelines and real-time processing

Javascript framework (We use mainly React.JS)

What do we offer you?

Perks and Benefits:

Work in a start-up environment backed by a well-rounded company

Flexibility in working hours and optionally remote

31 days off and 8% holiday allowance;

A good pension scheme at Zwitserleven;

Phone allowance

Do you have any questions about this position?

Do you have any questions about this position? We will be happy to answer them. Call to  Niels van der Linden (Managing Director) or Hessel Edelijn (Corporate Recruiter) at 088 115 2000

Have we aroused your interest for this position ? Then we look forward to receiving your cv.

You can apply via the application button.

"bringing ambitious challenges to a success together."

application procedure.

Does this vacancy appeal to you and are you curious about the application process? This goes as follows:

1. Apply
You have applied! We will discuss it internally and respond as soon as possible.
2. Phone call
We got acquainted briefly and want to get to know each other better.
3. First call
See if there is a match from both sides and if the expectations are correct.
4. Second call
We investigate a possible collaboration more closely.
5. Offer
We both see the match! Let’s make you a suitable proposal.
6. Contract
Your response to the offer is positive. We are going to finalize the collaboration!