Senior Software Engineer
Level inferred from job title
Job description
A Senior Software Engineer role on the five-person Contextualization Platform team, building high-performance backend systems and productionizing AI innovations for contextual advertising across the open web, CTV, and in-app environments.
At a glance
- Work mode
- Remote
What you'll do
- Design, build, and maintain high-throughput, low-latency services using Golang, supporting an RTB ecosystem handling over 500K queries per second
- Transform Data Science experiments, LLM capabilities, and AI-driven ideas into reliable production systems
- Develop APIs, services, and data pipelines that process large volumes of contextual data efficiently
- Prototype, test, and iterate on new approaches to contextual understanding across OpenWeb, CTV, and in-app environments
- Contribute to architectural decisions and continuously improve system performance, reliability, and scalability
- Work closely with Data Scientists, AI teams, and Product Managers to deliver solutions with measurable business impact
- Write clean, maintainable code while balancing quality, speed, and evolving business priorities
What we're looking for
- Strong hands-on Golang experience, building and maintaining backend services in production
- Solid understanding of distributed systems, particularly high-throughput or low-latency architectures
- Hands-on experience with LLM APIs, embeddings, or RAG, alongside a strong interest in AI technologies
- Experience with cloud infrastructure, observability, and production system monitoring
- Familiarity with Infrastructure as Code principles and tools
- Strong problem-solving skills and a pragmatic approach to delivering reliable, maintainable software
- Ability to work autonomously, adapt to changing priorities, and collaborate effectively with technical and non-technical stakeholders
Nice to have
- Experience with Python, Node.js, or TypeScript
- Experience in AdTech, particularly with RTB, OpenRTB, or CTV
- Experience processing large-scale data or building real-time advertising systems
Your team
Contextualization Platform team
A five-person team building the technology that understands content across the open web, Connected TV (CTV), and in-app environments.
Benefits
- A key moment of growth with real ownership and global impact
- Flexible work model with 100% remote or hybrid options
- Continuous learning through a learning platform and optional language classes
- A supportive, trust-based culture that values well-being
- Team activities and opportunities to connect beyond work
- Home office setup budget up to €1,000
- Paid trips to our HQ in Madrid
- MacBook Pro M3
Apply
About Seedtag
The leading Neuro-Contextual Advertising Company
Seedtag combines 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. Its proprietary AI, Liz, enables brands to connect with audiences across the open web and Connected TV without cookies or user tracking.
Mission
To transform advertising by proving that effectiveness and user privacy can truly coexist.
Key facts
- 500+ Seedtaggers
- 2014
- Madrid
- Neuro-Contextual Advertising / AdTech
- Founded in 2014 by two ex-Googlers
- 500+ Seedtaggers in 17 countries
- Backed by €250M in funding
- Operates as a global ad-tech leader
- Proprietary AI named Liz
What they value
- Outcome over Output
- Failure Is Allowed, Learning Is a Must
- We Are All Scouts
- We Are Data-Driven