Role: Senior / Principal Software Engineer Sector: Artificial Intelligence Job Type: Full-Time Salary: €80,000–€100,000 + Equity Contract Type: Direct employment with our client Location: Hybrid – Barcelona Language: Fluent Spanish is required Visa sponsorship is not available for this role (Only interested in speaking with candidates who are comfortable working in a hybrid model) Our partner is building next-generation AI-driven communication products that help businesses automate customer interactions, improve operational efficiency and generate actionable insights in real time.

What we are looking for

+5 years of production experience with modern web stack

Production experience with TypeScript, JavaScript, Python or C#

Experience with AI coding agents such as Claude Code, Cursor or Codex

Real Product mindset and ability to work autonomously

Comfortable with Docker, SQL, testing and scalable architecture

Fluent Spanish

Nice to have





Experience with LLMs, STT/TTS, OpenAI, Whisper, ElevenLabs or Deepgram

Experience with LangChain, LangGraph or similar AI orchestration tools

AWS/GCP, CI/CD and observability experience

Startup or early-stage product company experience

Previous experince leading a team or acting as a principal

What you’ll be doing

Building scalable APIs and services for real-time voice interactions

Developing product features end-to-end with React, TypeScript and AI infrastructure

Integrating LLM, STT and TTS workflows into production

Working on agentic and multi-agent workflows

Improving architecture, observability, testing and engineering quality

Working directly with the founders and senior team to shape the platform

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📌 Senior Software Engineer (Madrid)
🏢 Concentric Recruitment
📍 Madrid