Senior Full Stack / Backend Engineer
Summary
Build and own the real-time voice infrastructure and backend systems powering an autonomous voice agent platform, integrating LLMs, telephony, and CRMs with Node.js/Python/Go.
VoiceB | Fully Remote (Spain) | Engineering
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 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, 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)
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.
