Madrid, Spain Remote (Country)

mediasmart is hiring a Backend Engineer

About the Role

What You'll Do

Design and maintain a distributed backend system engineered for high availability and massive scalability, supporting millions of real-time requests daily. You'll write efficient, maintainable code in Node.js and contribute to services that demand millisecond-level responsiveness. Deploy frequently across a global cloud infrastructure, managing updates across numerous distributed nodes with confidence and precision.

Engage in peer code reviews to uphold code quality and share knowledge across the team. Work closely with operations and client-facing teams to diagnose and resolve performance bottlenecks, track down bugs, and support integrations with external partners. Your contributions will span the full development lifecycle, from design and implementation to debugging and optimization.

Requirements

You have at least two years of professional experience in backend development. You're proficient in modern JavaScript and Node.js, and you're comfortable writing and debugging server-side applications. You navigate Git via the command line with ease and understand the workflows behind collaborative development.

Fluency in Spanish is required, as it's the primary language for internal communication. You also communicate effectively in English, which is used in documentation, tools, and interactions with stakeholders. You thrive in environments where technology excellence is prioritized and continuous improvement is expected.

Preferred Qualifications

Experience in remote or distributed teams is a plus. While most of our backend is in Node.js, familiarity with Go is beneficial—though not required, as training is provided for motivated candidates. You may also bring experience with AWS services such as EC2, S3, Route53, CloudFront, load balancing, and Elastic Transcoder. Knowledge of distributed systems patterns—including message queues, failover mechanisms, and auto-scaling—is valued.

Experience with SQL, particularly using Google Cloud BigQuery, will help you succeed in analyzing and optimizing large-scale data flows across the platform.

Benefits

This role is remote-first, with team members located across Spain. You’re welcome to work from our central Madrid office if you prefer in-person collaboration. Enjoy flexible hours that support work-life balance and personal productivity rhythms.

Be part of a lean, impactful team where your work directly shapes the product. You'll have access to cutting-edge tools and technologies, along with resources to support ongoing learning. Every other Friday is dedicated to creative exploration—time to experiment with your own ideas and innovations.

Required Skills
JavaScriptNodeJSGoAWSEC2S3Route53Elastic TranscoderCloudFrontGCP BigQueryGitCI/CDDevOpsdistributed computingqueues JavaScriptNodeJSGoAWSEC2S3Route53Elastic TranscoderCloudFrontGCP BigQueryGitCI/CDDevOpsdistributed computingqueues
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About company
mediasmart
mediasmart is part of the Affle group, a global adtech company, and focuses on enabling advertisers to reach audiences across digital journeys in real time. The company operates a proprietary technology stack including a DSP, DMP, and Ad-Server, with direct connections to over 30 ad exchanges to buy display, video, native, and CTV ads across mobile apps, Connected TVs, DOOH, and desktop. It was one of the first players in the programmatic mobile ecosystem.
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Job Details
Department CTV-Sync technology team
Category backend
Posted 5 hours ago