Senior Full Stack / Backend Engineer (Ourense)

Senior Full Stack / Backend Engineer — Voice & AIVoiceB | Fully Remote (Spain) | Engineering—We're VoiceB. We're building the autonomous AI voice sales agent that's automating the last undigitized sales channel: the phone call. Top enterprise brands across telco, banking, insurance, energy and automotive are already using our platform to handle inbound B2C and B2B sales conversations end-to-end — qualifying, pitching, and closing without human agents.We're profitable, growing fast, and just getting started. Now we're hiring a Senior Engineer to help us scale the core platform that powers it all.—What you'll do• Design and build core systems behind our autonomous voice agent platform — real-time voice pipelines, LLM orchestration, telephony integrations and CRM connectors.• Own the voice infrastructure layer: Twilio, SIP trunks, WebRTC, and the real-time audio plumbing that makes a sub-second AI conversation feel human.• Ship full stack when needed — backend is your home, but you're comfortable touching the frontend to deliver end-to-end.• Work directly with our CTO and a small, senior engineering team where every line of code matters.• Integrate with Salesforce, HubSpot, ad platforms (Google, Meta) and enterprise CRMs.• Contribute to architecture decisions that will define how voice AI scales over the next 5 years.—✅ What we're looking for• 5+ years building production backend systems (Node.js, Python, Go, or similar).• Hands-on experience with Twilio and voice infrastructure — SIP, WebRTC, RTP, codecs, real-time audio. This is non-negotiable.• Experience integrating and working with LLMs, STT/TTS pipelines, or AI/ML systems in production.• Full stack capability — you can move across the stack when the product needs it.• Strong systems thinking: latency, concurrency, reliability at scale.• Advanced English (C1+). You'll work daily with enterprise customers and a general team.• Hard worker, ownership mindset, comfortable in a high-velocity startup environment.—Nice to have• Experience with conversational AI, IVR systems, or contact center platforms.• Background in CRM integrations (Salesforce, HubSpot).• Previous exposure to enterprise-grade compliance (GDPR, ISO 27001, SOC 2).—What we offer• Fully remote within Spain, with access to a coworking space if you want one.• Reporting directly to Luis Miguel, our CTO.• Market-rate salary + equity compensation after your first year.• A small, senior team working with some of the largest brands in Europe.• Real ownership over critical product areas — no layers, no politics.• A category-defining product at a category-defining moment for AI.—Location: Spain (fully remote)️ Language: English (advanced+), Spanish a plusReports to: CTOIf you want to build the infrastructure that's automating the world's last analog sales channel — and do it alongside a team that ships — let's talk.Apply directly through LinkedIn. Postúlate en Kit Empleo: kitempleo.es/empleo/6u03vi