Senior Full Stack Engineer — AI Voice Platform

About VoiceB

We build autonomous AI voice agents that close and qualify sales for large B2C enterprises — telcos, energy providers, insurers, banks. Our agents already run live inside companies like Vodafone España and Holaluz, and we're mid-rollout across an 8-market European deployment with Alpega/Teleroute. We're a small team moving fast, and we're building the commercial engine to match the product.

The role

We're looking for a senior full stack engineer to join a small, high-ownership engineering team building the core VoiceB platform — the systems behind SuperVoice, SuperQualification, Memory, and our outcome tracking. This is a remote role for someone based in Spain, working closely with our CTO and the rest of engineering.

What you'll do

• Build and ship features across the platform: backend services, APIs, third-party integrations (Salesforce, HubSpot, Twilio, SIP/WebRTC), and internal tooling
• Own features end to end — design, build, test, deploy, monitor
• Partner directly with the CTO and founders on architecture decisions as the platform scales
• Contribute to security and compliance hardening for enterprise clients

What we're looking for

• 4+ years of full stack experience, comfortable owning features end to end on a small, fast-moving team
• Strong in a modern JS/TS stack (React/Node or similar); comfortable with cloud infrastructure (AWS/GCP)
• Based in Spain, fully remote, able to overlap with Barcelona working hours
• Product-minded — you care about what gets built, not just how

Nice to have

• Experience with real-time or telephony systems (SIP, WebRTC, Twilio)
• Experience integrating LLMs or other AI/voice tooling into production systems
• Early-stage startup experience

What we offer

• Competitive salary + equity
• Fully remote (Spain-based)
• Direct influence over the architecture of a product still being defined

We're hiring deliberately, not urgently — we'd rather find the right person than fill the seat fast. If this sounds like your kind of problem, we'd love to hear from you.