Senior Software Engineer

About the role

Seedtag is looking for a Senior Software Engineer to join its five‑person Contextualization Platform team. You will help build high‑performance backend services that power neuro‑contextual advertising across the open web, Connected TV and in‑app environments.

Key responsibilities

• Design, develop and maintain high‑throughput, low‑latency Go services that handle over 500K queries per second in a real‑time bidding ecosystem.
• Integrate AI/ML components such as LLM APIs, embeddings and Retrieval‑Augmented Generation into production systems.
• Build scalable APIs, data pipelines and micro‑services for processing large volumes of contextual data.
• Collaborate with data scientists, AI teams and product managers to turn research prototypes into reliable, business‑impacting solutions.
• Contribute to architectural decisions and continuously improve system performance, reliability and observability.

Required profile

• Strong hands‑on experience with Golang in production backend services.
• Solid understanding of distributed, high‑throughput or low‑latency architectures.
• Experience with cloud infrastructure, monitoring and Infrastructure‑as‑Code (e.g., Terraform).
• Ability to work autonomously, adapt to changing priorities and collaborate with both technical and non‑technical stakeholders.

Required skills

• Go / Golang
• Python, Node.js, TypeScript (nice to have)
• LLM APIs, embeddings, Retrieval‑Augmented Generation
• Microservices, APIs, distributed systems
• Cloud platforms, observability tools, Terraform

What we offer

• Opportunity to own impactful features in a fast‑growing ad‑tech leader.
• 100% remote or hybrid work model (remote contracts available in several European countries).
• Home‑office budget up to €1,000, MacBook Pro M3, paid trips to HQ in Madrid.
• Continuous learning platform and optional language classes.
• Supportive, trust‑based culture focused on well‑being.