Full-Stack Engineer

We’re looking for a Full-Stack Engineer to join our team and help shape the future of contextual advertising as we continue to expand globally.

Who We Are

At Seedtag, our goal is to lead the change in the advertising industry because we believe that effective advertising should not be at odds with users’ privacy.

Every day, our teams develop new services that reach over 200 million users worldwide with fast response times to ensure that we deliver the best user experience. We’re fully committed to the DevOps culture, where we provide the platform that our Software Developers and Data Scientists use to manage over 100 different microservices, pushing dozens of changes to production every day. All of this is built on top of Kubernetes in Google Cloud Platform and Amazon Web Services.

If you are interested in joining one of the fastest-growing scale-ups in Europe and working on massive scalability challenges, this is the place for you.

As a Full-Stack Engineer in the AdServing team, you’ll help shape two of Seedtag’s most critical tools:

• Our SDK, the agent embedded in 200M+ devices daily, responsible for rendering ads in real time.
• Studio Pro, the creative tool used by designers to build contextual ads across multiple formats and devices.

You’ll be working with modern, typed front-end languages (Rescript and React), building performant interfaces and reliable APIs, all while collaborating with design and backend teams to make sure everything just works.

We’re looking for someone who enjoys solving hard problems, cares about maintainable code, and is ready to make key architectural decisions as the product evolves.

Your day-to-day will include:

• Designing and implementing client-side features for the SDK and Studio Pro.
• Developing scalable backend APIs to support dynamic creative logic and data syncing.
• Collaborating with designers, backend engineers, and product stakeholders to align on needs and priorities.
• Working across the stack, from micro frontends to backend services.
• Applying and advocating for clean code, testing, performance, and maintainability.
• Taking ownership of key features and mentoring others as the team grows.

How do we work?

• Do you know them too? We build high-throughput microservices, APIs, SDKs, dev tools…
• Have you done that before? We practice DevOps, Peer Reviews, Continuous Discovery, Delivery and Integration.
• You like that workflow? We collaborate on Slack, Notion, JIRA, Github.

Our core values

• Outcome over output

Our core tech values reflect our commitment to delivering exceptional results, fostering a culture of continuous learning, and always putting the customer’s needs first. We believe that success comes from focusing on the outcomes rather than just the output. Our tech team aims to solve problems that make a meaningful difference, and we measure our success by the impact we have on the customer.

• Failure is allowed, learning is a must

We also recognize that failure is an inevitable part of the innovation process. Our team understands that setbacks are opportunities to learn and grow. We believe in testing early and often, and we continuously iterate and improve until we arrive at the best solution.

• We are all scouts

Another core value we hold is that we are all scouts. We believe in leaving things better than we found them. This means we take ownership of our work and strive to improve the systems and processes we touch. We encourage our team members to be proactive in identifying areas for improvement, and we value those who take the initiative to implement positive changes. Our goal is to leave a lasting, positive impact on our projects and our team.

Lastly, our team is data-driven. We believe that making informed decisions based on data is crucial to our success. Our team uses data to guide our decision-making process and to identify opportunities for improvement. We are committed to using data to continuously monitor and optimize our models and processes to ensure that we are delivering the best possible outcome for our customers.

We have to support 120k requests per second running with ML models in production answering within 10 milliseconds! We have this running in production with Python and GoLang microservices using datalakes, GCS, Redis, Kinesis or Kafka. All this is constantly deployed in GCP using Kubernetes and other kinds of production stacks. The current stack outputs 20 TB of daily data having them ready to use for analytics and more with easy and low latency access.

In the rest of the company, we also develop in Typescript for Nodejs and Scala making use of technologies like Kafka, Druid and MongoDB all over the Google Cloud Platform.

What You’ll Need to Succeed

• You’re a full-stack engineer with 5+ years of experience. You’re comfortable jumping between front-end and back-end, and you’ve built and maintained production-level apps using typed languages.
• You’ve contributed to developer-facing tools, SDKs, or design systems, and enjoy solving complex problems at the intersection of UX and code.
• You write clean, maintainable code and know how to apply software engineering principles to keep things simple and robust.
• You’re a strategic thinker, able to connect product needs with technical decisions and architecture.
• You enjoy a good challenge and love finding elegant solutions to complex problems.
• You’re always learning and staying up to date with new tech, frameworks, and practices.
• You’re a strong communicator who thrives in collaborative environments.
• You’re adaptable and used to working in fast-paced environments where priorities shift quickly.

Why Join Seedtag?

Growth & Opportunity: A key moment to join with vast career development prospects.

Flexibility: At Seedtag, we trust you to balance work and life effortlessly with the option to a 100% remote (Please note that while we operate as a 100% remote company, we can only extend contracts within Europe in countries where we have established legal entities: Spain, Italy, the UK, Belgium, the Netherlands, France, and Germany) or hybrid work setup, depending on what works best.

Learning & Development: Online courses and optional English or Spanish group classes.

Inclusive Culture: We foster a supportive environment that values personal growth.

Fun & Connection: Participate in team activities, company offsites, and more!

• Gympass: Access to wellness programs and fitness classes.
• Seedsave Program: Exclusive discounts to help you save for the future.
• Build your home office with a gross budget of up to 1K€ (external screen, chair, table...)
• Paid travels to our HQ in Madrid to work p2p with your squad members

Ready to join the Seedtag adventure?

Send us your CV and let’s grow together!

At Seedtag, we’re committed to creating an inclusive environment where everyone can thrive. We welcome diverse perspectives as they fuel our innovation and growth. Please let us know if you require accommodations during the hiring process and we’ll ensure a positive and accessible experience.