Backend Software Engineer

Why are you looking for a job?

If your answer ticks all the boxes, this could be the start of a great collaboration.

• You have a curious mind - You won't understand what we're talking about if you don't 🤔
• You want to learn more around technology - You won't survive if you don't 😱
• You want to make the world a bit better - We don’t like you if you don’t 😎

We happen to be just like that as well. We like hacking things here and there (you included) and create scalable solutions that bring value to the world.

SquareDev? 🐿️

We use state-of-the-art technology to build solutions for our customers and our partners' customers. We make sure we stay best-in-class by participating in research projects across Europe, collaborating with top universities and enterprises on AI, Data, and Cloud.

About QnR Group

SquareDev is a member of the QnR Group, a leading technology organization specializing in end-to-end custom software solutions, Artificial Intelligence, Cybersecurity, SAP, ServiceNow and FinTech solutions.

As part of QnR Group's ongoing expansion — both in Greece and internationally — we are continuously hiring across a wide range of tech roles. Successful candidates may be hired by QnR Group, or another company within the Group, depending on the role and project.

Role overview

We are looking for a Back-End Software Engineer to develop and maintain secure, scalable server-side applications. Working alongside front-end developers and cross-functional teams, you will implement core business logic, design data storage solutions, and ensure software quality through robust testing and documentation practices.

Requirements

The ideal candidate will be responsible for:

• Develop and maintain back-end applications, implementing business logic and integrating server-side functionality with front-end components.
• Design and implement scalable data storage solutions and RESTful APIs.
• Apply security best practices across authentication, authorization, input validation, and secure logging.
• Optimize applications for performance and scalability, including cloud service configuration (serverless, storage, managed Kubernetes).
• Write clean, well-structured code and maintain code integrity across the codebase.
• Perform unit and integration testing, debug and fix issues, and validate code changes prior to deployment.
• Set up and query monitoring tools to troubleshoot problems and identify areas for improvement.
• Produce and maintain technical documentation for all developed components.

To excel in this role, you'll need:

• Proficiency in back-end programming languages (Java, PHP) and frameworks such as Spring Boot, Hibernate, and Node.js.
• Experience with APM tools (Dynatrace, Splunk, Elastic APM) and familiarity with OpenTelemetry for observability.
• Solid knowledge of relational databases (PostgreSQL, Oracle, MySQL) including complex SQL, and experience with NoSQL stores (MongoDB, CouchDB, CosmosDB).
• Familiarity with Git workflows (GitFlow, trunk-based development) and legacy SVN systems.
• Experience designing and documenting secure RESTful APIs using OpenAPI/Swagger standards.
• Knowledge of containerization and orchestration technologies (Docker, Kubernetes).
• Understanding of authentication and authorization standards (OAuth 2.0, OpenID Connect, JWT).
• Strong English communication skills, French is an asset.

Nice to have:

• One of the following or an equivalent: AWS Certified Developer – Associate, Microsoft Azure Developer Associate, or CNCF Certified Kubernetes Application Developer (CKAD).