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

A continuación se detalla todo lo que necesita saber sobre lo que implica esta posibilidad, así como lo que se espera de los solicitantes.

(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 TypeScript / 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




- 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, o

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