Full Stack / Backend Engineer - Voice & AI Voice B

{ "@context": "http://schema.org", "@type": "JobPosting", "baseSalary" : { "@type": "MonetaryAmount", "currency": "EUR", "value": { "@type": "QuantitativeValue", "value": 0.00, "unitText": "MONTH" } }, "datePosted": "2026-04-30", "validThrough" : "2026-06-27", "description": "Senior Full Stack / Backend Engineer - Voice & AI Voice B | Fully Remote (Spain) | Engineering - We're Voice B. 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 B2 C and B2 B 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, Web RTC, 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, Hub Spot, 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, Web RTC, 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 global 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, Hub Spot). * 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 plus Reports to: CTO If 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 Linked In. ", "employmentType": "FULL_TIME", "industry": "Senior Full", "jobLocation" : { "@type": "Place", "address": { "@type": "PostalAddress", "streetAddress": "Valencia", "addressLocality": "Valencia", "addressRegion": "Ourense", "addressCountry": "ES", "postalCode": "n/a" } }, "salaryCurrency": "EUR", "title": "Senior full stack / backend engineer - voiceb.ai", "hiringOrganization" : { "@type" : "Organization", "logo" : "https://logo.jobs-search.org/17207845.jpg", "name" : "VOICEB.ai" } }