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 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
* 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

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