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

¿Tiene lo que se necesita para triunfar? La siguiente información debe ser leída atentamente por todos los candidatos.

[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, observability, testin

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