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Senior Software Engineer (Agentic)

Remote, Madrid·Full-time·Added 25 days ago

Refinery89

18 open roles

Overview

Job details

  • Permanent contract

    Full-time hours.

  • Fully remote

    Only from certain places, per the ad: “work from anywhere within the European timezone (CET ±2h)”

Requirements

  • Have the right to work in Spain

    Refinery89 doesn't mention sponsorship in the ad.

  • Work in English

    English is required, per the ad.

  • Have 5+ years of experience

    Senior-level role.

Pay & benefits

What you'll get

  • 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.

  • 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.

Requirements

Languages

  • PHP (required) · JavaScript / Node.js · Python

  • Rust (nice to have)

The role

What you'll do

  • 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.

Job description

📍 Full Remote · European Timezone · Professional English Required

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.

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.

About Refinery89

Refinery is a technology company that provides a platform for managing and optimizing digital advertising campaigns. The company's software helps brands and agencies automate, measure, and improve their performance across various digital channels, with a focus on data-driven decision-making and efficiency. Refinery operates globally, with a presence in the US and Europe, and serves a range of clients from direct advertisers to agencies.

In Spain, Refinery has established a growing office in Madrid, which serves as a hub for its Southern European operations. The company is known for a data-centric, performance-oriented culture, and its Spanish office actively hires international talent, particularly in technical roles like data science, product management, and software engineering. For international professionals, Refinery offers a dynamic, fast-paced environment where English is commonly used, making it an accessible entry point into the Spanish tech ecosystem.

Founded
2015
Employees
100–500
Headquarters
New York, USA
In Spain
Madrid

Good to know if you are moving

  • Refinery's Madrid office is a key hub for its Southern European operations, offering a path for international hires to work in Spain.
  • The company's work culture is described as data-driven and product-focused, which can be appealing for professionals with a technical background.
  • As a US company with a Spanish office, Refinery offers an international environment where English is commonly spoken, easing the transition for non-Spanish speakers.
  • The company has a relatively small, agile team, which can mean faster decision-making and more direct impact for new hires.
  • Refinery's roles in Spain span product management, data science, and software engineering, indicating a demand for technical talent.
All open roles at Refinery89
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