About the Role
HTS Assist is Hopper's agentic AI assistant for travel, resolving flight changes, cancellations, refunds, and bookings over chat and voice for some of the world's largest travel brands. We're looking for a senior full stack engineer to anchor this product, owning the realtime and voice layer end to end while building across React/TypeScript front ends, Scala and Python services, and cloud infrastructure. The team is lean and senior, ownership is broad, and the path from your code to a traveler's phone call is short.
What would your day-to-day look like
Own the voice channel end to end, including telephony and CPaaS integrations (e.g., Twilio, Amazon Connect), streaming speech-to-text and text-to-speech pipelines, realtime model orchestration, and latency and quality budgets
Build product features across the stack, including web chat front ends in React/TypeScript, backend services in Scala and Python, and infrastructure on GCP
Design for multi-tenant scale, with one codebase serving many partners through configuration rather than forks




Build the safety and compliance plumbing enterprise partners audit, including guardrails, content filtering, and PII redaction integration points
Keep revenue-critical deployments healthy through observability, alerting, incident response, and SLA performance
Build the platform capabilities forward-deployed engineers configure for partner telephony integrations and go-lives
Raise the engineering bar through code review, architecture reviews, and mentoring
An adecuado candidate has
6+ years of software engineering experience, with senior-level ownership of production systems and genuine full-stack range
Hands-on realtime systems experience, such as voice applications, WebRTC/SIP, streaming media, or comparable low-latency products
Strength in a modern front end (React, TypeScript) and depth on the backend (Scala or another JVM language, and/or Python), along with cloud infrastructure experience on GCP or AWS
A track record

📌 Senior Full Stack Engineer (España)
🏢 Hopper
📍 España