Backend Software Engineer

We’re looking for a Backend Software Engineer to join our tech team and help build the future of neuro-contextual advertising at global scale.

Who We Are

At Seedtag, our mission is to transform advertising by proving that effectiveness and user privacy can truly coexist.

As the leading Neuro-Contextual Advertising Company, we combine Artificial Intelligence, Natural Language Processing, Computer Vision, and neuroscience to understand not only what content is about, but how it makes people feel and what they intend to do next.

Our proprietary AI, Liz, enables brands to connect with audiences across the open web and Connected TV without cookies or user tracking. Founded in 2014 by two ex-Googlers, Seedtag has grown to 700+ Seedtaggers in 17 countries, backed by €250M in funding, and operates today as a global ad-tech leader.

If you enjoy solving complex engineering challenges and building AI-driven systems at scale, you’ll feel right at home here.

Your Challenge

As Backend Software Engineer, You Will

• Be responsible for building and improving services which will have a direct impact on our client’s advertising KPIs and operational efficiency.
• Work on end-to-end projects, taking solutions from concept to production, and focusing on creating scalable, efficient, and impactful solutions.
• As a member of our engineering team, you will develop new projects mainly on the backend side, but sometimes, you’ll support particular frontend needs. You’ll be in charge of the CI/CD, dimensioning production instances and scaling.
• Provide an analytical mindset, being able to go to our data lake in order to validate your own hypothesis and try to get your own conclusions to discuss afterwards with the team.
• Collaborating closely with our cross-functional teams, your work will be aligned with business goals and drive the practical application of your solutions.

Our Core Values

Outcome over Output

We measure success by impact and value, not by volume of features or lines of code.

Failure Is Allowed, Learning Is a Must

Experimentation is key to innovation. We test early, iterate often, and learn fast.

We Are All Scouts

We take ownership and leave things better than we found them.

We Are Data-Driven

Data informs our decisions and helps us continuously improve our systems and results.

Tech Stack

We operate at large scale, supporting up to 120k requests per second, with ML models responding in under 10 milliseconds and processing 20 TB of data daily.

Our Stack Includes

• Languages: Python, Go, TypeScript, Scala
• Cloud & Infrastructure: Kubernetes, GCP, AWS
• Streaming: Kafka, Kinesis
• Data: Datalakes, GCS, Redis, Druid, MongoDB
• Architecture: 100+ microservices, DevOps-driven, continuous deployment

What You’ll Need to Succeed

• You bring 3-5 years of experience into backend software engineering, from the conceptualization of the problem to the deployment in production and validation that works.
• You have collaborated on some front-end projects even if it’s not your strongest skill.
• You are a DevOps-oriented engineer who is responsible for the CI/CD of the services you build, you understand how to do the sizing of production deployment and how to troubleshoot if something is not working as expected.
• You deeply understand the problem you are trying to solve. You measure the outcome of the development you do.
• You have worked in related disciplines which can include Data engineering pipelines, infrastructure provisioning or deployment of ML models in production.

Why Join Seedtag?

• A key moment of growth with real ownership and global impact.
• Flexible work model with 100% remote or hybrid options. (Remote contracts available in Spain, Italy, UK, Belgium, Netherlands, France, and Germany.)
• Continuous learning through a learning platform and optional language classes.
• A supportive, trust-based culture that values well-being.
• Team activities, offsites, and opportunities to connect beyond work.

Additional Perks

• Home office setup budget up to €1,000
• Paid trips to our HQ in Madrid
• MacBook Pro M3

Ready to Join the Seedtag Adventure?

At Seedtag, we create an environment where everyone can thrive. If you need accommodations during the hiring process, let us know and we’ll ensure a positive experience.

Send us your CV and let’s build the future of neuro-contextual advertising together.