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Senior Software Engineer - Backend

Fecha: 02-oct-2021

Ubicación: MADRID, ES

Empresa: Telefonica S.A.


Telefonica CTO-Novum is seeking talented engineers to join our Engineering team. The challenges faced every day in extending and improving the Telefonica user experience require vast knowledge in how to produce highly maintainable and extensible object-oriented code. Our engineers must feel the need to build a product that works fast and flawlessly, be passionate about eliminating any problems as soon as they are discovered and take pride in doing so. 

The CTO-Novum group builds and operates the main application for Telefónica customers worldwide reaching more than 30 million active users. We work to build new and innovative products and to ease the access to all the services that Telefónica offers. 


Our mission is to guide our customers along their lifecycle, by being the center of the digital relationship with Telefónica 



  • High-quality design of product and infrastructure components for maintainability, robustness and scalability. 

  • Develop and maintain software components in the language most appropriate to the problem. The main languages in use are Java/Kotlin, Python and PHP, but there are multiple other ones. 

  • Optimize application performance, with respect to CPU utilization, network traffic, data storage size, response time, and concurrency. 

  • Writing and maintaining effective automated test suites for delivered components. 

  • Analyze and eliminate security vulnerabilities, and bottlenecks in system performance. 

  • Working together with Site Reliability Engineers to design and deploy key infrastructure components and monitor them. 

  • Defining and collecting relevant data for tracking component health and performance. 

  • Debug issues on server-side services, the interactions between services and the platform they run on. 

  • New features requisites understanding to design a solution to cover them. 


  • Computer Science, Telecommunication Engineer, etc. 



  • Extensive knowledge of kubernetes, docker and docker-compose. 

  •  Extensive knowledge of object-oriented programming and software architecture (preferably Java/Kotlin, other OOO languages are acceptable). 

  • 3+ years experience solving challenging performance problems, preferably related to web applications and distributed architectures based on microservices. 

  • Experience deploying services and software in a real production environments. 

  • Strong will to adhere to best practices in OO development and a need to leave well-structured code in your tracks. 

  • Deep knowledge of relational databases (MySQL) and other approaches to data management, particularly performance aspects. 

  • Strong analytical and problem-solving skills. 



Nice to have: 

  • Backend Development: Java & Kotlin, Python, Vert.x framework, Retrofit REST client, JAX-RS (Jersey) REST server, Dependency injection systems (Guice), Experience with unit/integration testing (JUnit/Spock) 

  • Tools: Git, Maven, Docker and Kubernetes 

  • Infrastructure: Metrics and log systems as Graphite, Prometeus, Grafana, Sentry and Elastic / Fluentd / Kibana 

  • DBA: MySQL 

  • Cloud: Azure, PaaS, IaaS 



  • 5+ years of experience 


  • English (professional competence) 

If you join Telefónica


You join almost 100 years of history, you join a team of 106 nationalities present in more tan 35 countries. You join a team that works to connect people wherever they are. We are leading the digital revolution with the enthusiasm of the first day in all our businesses, creating the best digital ecosystem for our clients: network, IoT, cloud, security, innovation etc. Here, at Telefónica you count with everything you need to be the best you. We need people like you that wants to take this challenge of creating the Telefónica of tomorrow.


Telefonica is committed to the new working ways. Under our proposition “Disconnect to Reconnect” we have applied the Digital Disconnection.




We strongly believe diverse and inclusive teams become more innovative and they achieve improved results. Telefonica aims to promote and guarantee a place for everyone, just the way we are: gender, age range, sexual orientation and/or identity, culture, creed, disability or any other personal condition.