Full Remote · European Timezone · Professional English Required
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About the Role
We're looking for a Senior Software Engineer with an Agentic mindset — someone who doesn't just write code, but builds systems that think, act, and adapt. You'll work on a production AdTech platform with real business impact, and you'll increasingly work alongside AI agents and design agentic workflows as part of your daily engineering practice.
This is not a ticket-execution role. We expect you to bring judgment, ask the hard questions, design thoughtfully, and genuinely care about the quality of what you ship — whether that code was written by you, assisted by AI, or executed autonomously by an agent you designed.
Responsibilities
- Design, develop, and maintain robust, scalable backend services following Domain-Driven Design (DDD) principles.
- Take full technical ownership of features — from design through deployment and monitoring.
- Build and orchestrate agentic workflows: autonomous pipelines where AI models (Claude, LLMs) take actions, call tools, and solve tasks with minimal human intervention.
- Actively participate in architecture decisions with strong analytical thinking and technical depth.
- Ensure code quality through SDD, TDD, and BDD methodologies, with sharp attention to detail.
- Collaborate on code reviews, refinements, and technical planning.
- Proactively identify and address technical debt, performance bottlenecks,



and security risks (OWASP, SOLID).
- Build and maintain CI/CD pipelines across Bitbucket, GitLab, or GitHub.
- Produce well-reasoned technical designs before writing the first line of code.
Tech Stack
Languages
- PHP (required) · JavaScript / Node.js · Python
- Rust (nice to have)
Frameworks & Tools
- Laravel · Pest · Tailwind CSS
- AWS: Lambda, SAM Templates, S3, CloudFront
- Terraform · Playwright · Robot Framework · Cypress
- Grafana · k6 · Postman
Agentic & AI Tooling
- Claude (Anthropic) · Kiro
- Experience building or working with LLM-powered agents, tool use, MCP integrations, or prompt engineering at an engineering level
Platform & Collaboration
- Bitbucket · Jira / Atlassian suite
AdTech (nice to have)
- Google Ad Manager (GAM)
- Prebid.js · Prebid Server
Methodologies & Principles
- SDD (Spec-Driven Development) · TDD · BDD
- SOLID · DDD · OWASP
- CI/CD pipelines (Bitbucket Pipelines, GitLab CI, GitHub Actions)
What We're Looking For
- 5+ years of experience in backend or full-stack software development.
- Practical experience with agentic AI systems — building agents, designing tool use, working with LLM APIs,



or automating complex workflows with AI.
- Strong technical analysis and design skills: you can break down complex problems, propose well-reasoned solutions, and think through the implications of architectural decisions.
- Critical thinking: you don't execute blindly. You question, challenge, and improve — including the outputs of AI tools.
- Attention to detail: the code you ship is clean, tested, and documented. You apply the same standard to AI-generated code.
- True ownership: you're accountable for what you build — in production, over time.
- Autonomy: you know how to move forward without hand-holding, and when to raise a flag.
- Proactive attitude: you surface improvements, catch problems before they become incidents, and share knowledge freely.
- Eagerness to learn: the agentic era is moving fast, and you're moving with it.
- Fluent professional English, written and spoken. The team is fully remote and multicultural.
What We Offer
- Full remote — work from anywhere within the European timezone (CET ±2h).
- Small, technical team with minimal overhead.
- Direct impact: your decisions ship to production.
- A culture of honest feedback and continuous improvement.
- Modern tooling — including cutting-edge AI — and freedom to propose new approaches. xqbhyrx
- A front-row seat to the agentic engineering shift, not just as a user but as a builder.
If this sounds like you and you want to build something that matters, we'd love to hear from you.

📌 Sr. Software Engineer (Agentic) (Madrid)
🏢 Refinery89
📍 Madrid