Senior Full Stack Engineer (Realtime & Voice) Customer Experience Platform

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 mentoringAn ideal 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 designing, building, and maintaining RESTful APIs, microservices, or event-driven systems • Familiarity using AI coding tools as a standard part of their workflow, with the judgment to review, correct, and own everything that ships • An operable-systems mindset, covering SLAs, observability, on-call rotations, and rollback plans • The ability to break down complex problems, make pragmatic tradeoffs, and ship iteratively, backed by strong communication across product, design, and operations • Bonus points for conversational AI or LLM orchestration experience, including speech technologies such as Deepgram, ElevenLabs, Whisper, or OpenAI Realtime • Bonus points for working knowledge of cloud telephony or CPaaS platforms such as Twilio, Amazon Connect, Genesys, or LiveKit • Bonus points for experience building customer service, CRM, contact center, or workflow automation tools • Familiarity with travel industry technologies (PSS/GDS, hotel PMS/CRS) is a plus, though not requiredPerks and benefits of working with us • Well-funded and proven startup with large ambitions, competitive salary, upsides of pre-IPO equity packages • Hopper covers 100% of the premiums for the employee for a group insurance plan through Vitality Health • Automatic contributions when you start with Hopper through Smart Pension • Please ask us about our very generous parental leave, much above industry standards • Access to co-working space on demand through FlexDesk and a work-from-home stipend • Carrot Cash travel stipend • Unlimited PTO • Entrepreneurial culture where pushing limits and taking risks is everyday business • Open communication with management and company leadership • Small, dynamic teams, massive impactAbout Hopper At Hopper, we are on a mission to become the leading travel platform globally, powering Hopper's mobile app, website and our B2B business, HTS (Hopper Technology Solutions). By leveraging massive amounts of data and advanced machine learning algorithms, Hopper combines its world-class travel agency offering with proprietary fintech products to bring transparency, flexibility and savings to travelers globally. We have developed several unique fintech solutions that address everything from pricing volatility to trip disruptions, helping people travel better and save more on their trips.The Hopper platform serves hundreds of millions of travelers globally and continues to capture market share around the world. The Hopper app has been downloaded over 120 million times and has become largely popular among younger travelers, with 70% of its users being Gen Z and millennials.While everyone knows us as the Gen Z and Millennial travel app, Hopper has evolved to become much more than that. In recent years, we've grown into a travel fintech provider, commerce platform, and global travel agency that powers some of the world's largest brands.Through HTS, our B2B division, the company supercharges its partners' direct channels by integrating