Principal, Software Engineer (L5) Remote - Spain

Company: Twilio

See yourself at Twilio

Join the team as our next Principal Full Stack Software Engineer within our Flex teams.

Who we are & why we’re hiring

Twilio powers real-time business communications and data solutions that help companies and developers worldwide build better applications and customer experiences.

Although we're headquartered in San Francisco, we have presence throughout South America, Europe, Asia and Australia. We're on a journey to becoming a globally anti-racist, anti-oppressive, anti-bias company that actively opposes racism and all forms of oppression and bias. At Twilio, we support diversity, equity & inclusion wherever we do business. We employ thousands of Twilions worldwide, and we're looking for more builders, creators, and visionaries to help fuel our growth momentum.

About the job

This position is needed to bring the programmability of Flex to the next level! 

Twilio Flex is a programmable cloud contact center platform that enables mission critical customer communications for businesses such as Lyft, Shopify and many others. Flex SDK is a client side library that provides a higher degree of customisation of the contact centers allowing businesses to leverage the best of the Twilio services while maintaining the uniqueness of their own brand. 


In this role, you’ll:

  • Work with multiple teams to deliver delightful developer experiences. Collaborate with the Tech Lead on the definition and  implementation of these experiences with your deep web development experience.
  • Drive and encourage standardization of standard methodologies in front end code.
  • Collaborate with the team to design and develop the new API’s and features end-to-end. 
  • Create an atmosphere of quality by championing testing standard methodologies and engineering efficiency.
  • Constantly look for areas of improvement in processes and systems, suggest optimisations.
  • Collaborate with other Flex teams based in Tallinn, Prague and London and other Twilio teams that are globally distributed. 


Not all applicants will have skills that match a job description exactly. Twilio values diverse experiences in other industries, and we encourage everyone who meets the required qualifications to apply. While having “desired” qualifications make for a strong candidate, we encourage applicants with alternative experiences to also apply. If your career is just starting or hasn't followed a traditional path, don't let that stop you from considering Twilio. We are always looking for people who will bring something new to the table!


  • 7+ years of Engineering experience, developing and maintaining high traffic web applications.
  • Proven ability to architect complex web systems (e.g. micro frontends).
  • Significant experience with browser APIs (REST, GraphQL, GRPC, and Protobuf) and optimizing front end performance.
  • Expert level coding skills with JavaScript, TypeScript..
  • Proven ability to architect and deliver highly interactive, engaging applications that are usable, performant, and scalable.
  • Knowledgeable of continuous deployment techniques, client-side bundling with webpack, and deployment infrastructure (e.g. CDNs, edge functions, etc.).
  • Experience with releasing open-source JavaScript libraries via npm.
  • Bachelor's degree in Computer Science, Engineering or a related field, or equivalent training, fellowship, or work experience.


  • Experience with Java is a plus
  • Experience with distributed systems and hands-on with at least a few of the big data technologies such as Spark, Kafka etc.
  • Experience with web auth standards and JWT(E)
  • Knowledgeable of continuous deployment techniques, client-side bundling with WebPack, and deployment infrastructure (e.g. CDNs, edge functions, etc.).
  • Bachelor's degree in Computer Science, Engineering or a related field, or equivalent training, fellowship, or work experience. 
  • Experience building client side SDKs is a plus


This role will be based in our Tallinn, Estonia office or remote and based in Europe (Germany, UK, Ireland, Spain, Netherlands, Estonia)

What We Offer

There are many benefits to working at Twilio, including, in addition to competitive pay, things like generous time-off, ample parental and wellness leave, healthcare, a retirement savings program, and much more. Offerings vary by location.

Twilio thinks big. Do you?

We like to solve problems, take initiative, pitch in when needed, and are always up for trying new things. That's why we seek out colleagues who embody our values — something we call Twilio Magic. Additionally, we empower employees to build positive change in their communities by supporting their volunteering and donation efforts.

So, if you're ready to unleash your full potential, do your best work, and be the best version of yourself, apply now!

If this role isn't what you're looking for, please consider other open positions.

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