Role:
Senior / Principal Software Engineer Job Type: Full-Time 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. They are now looking for a Senior/ Principal Software Engineer to help scale the platform behind their voice agents, owning features end-to-end across their Type Script / Python stack and working on AI pipelines, LLM orchestration, STT/TTS, prompt workflows and real-time systems. What we are looking for
+5 years of production experience with modern web stack 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, Eleven Labs or Deepgram Experience with Lang Chain, Lang Graph or similar AI orchestration toolsAWS/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, Type Script 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
#J-18808-Ljbffr

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