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

Full Stack Engineer · Senior · Full Time · Remote

England - Remote · RemoteUSD 165k – 240k4d ago
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Role

What you'll do.

Lead the development of HTS Assist, Hopper's agentic AI assistant for travel, owning the realtime and voice layer end-to-end across React/TypeScript frontends, Scala and Python backend services, and GCP cloud infrastructure. This role requires 6+ years of full-stack software engineering experience with genuine hands-on expertise in realtime systems, voice applications, and production system ownership in a lean, senior team where code ships directly to travelers globally.

Responsibilities

  • Voice Channel Ownership: Own the voice channel end-to-end, including telephony and Communications Platform as a Service (CPaaS) integrations such as Twilio and Amazon Connect. Architect and maintain streaming speech-to-text and text-to-speech pipelines, manage realtime model orchestration, and establish latency and quality budgets for production systems serving enterprise travel partners.
  • Full-Stack Feature Development: Build product features across the entire technology stack, including web chat frontends in React and TypeScript, backend microservices in Scala and Python, and cloud infrastructure on Google Cloud Platform (GCP). Implement RESTful APIs and event-driven systems that power customer interactions at scale.
  • Multi-Tenant Architecture Design: Design and implement multi-tenant systems with a single codebase that serves multiple travel partner brands through configuration-driven approaches rather than code forks. Ensure scalability, isolation, and reliability across diverse partner integrations and deployment scenarios.
  • Safety and Compliance Infrastructure: Build enterprise-grade safety and compliance systems including guardrails, content filtering, and Personally Identifiable Information (PII) redaction integration points. Develop the plumbing that enables partners to audit and validate compliance with their security requirements.
  • Production System Reliability: Maintain revenue-critical deployments through comprehensive observability, alerting strategies, incident response procedures, and Service Level Agreement (SLA) performance monitoring. Implement monitoring solutions that provide visibility into system health and enable rapid response to production issues.
  • Partner Integration Platform: Build and evolve platform capabilities that forward-deployed engineers can configure for partner telephony integrations and go-lives. Provide abstractions and tools that enable partners to integrate voice capabilities with minimal friction.
  • Engineering Excellence: Raise the engineering bar across the team through rigorous code reviews, architecture reviews, and mentoring. Share knowledge around realtime systems, voice technologies, and production operational practices to strengthen team capabilities and decision-making.

Qualifications

What we look for.

Technical

  • Full-Stack Web Development

    Demonstrated strength in modern frontend frameworks (React, TypeScript) with simultaneous depth on the backend (Scala or another JVM language, and/or Python). Proven ability to design, build, and maintain systems across frontend, backend, and infrastructure layers.

  • Realtime Systems Architecture

    Hands-on experience building low-latency, realtime systems including voice applications, WebRTC/SIP protocols, streaming media handling, or comparable mission-critical realtime products. Understanding of latency budgets, quality metrics, and performance optimization in realtime contexts.

  • Voice and Telephony Integration

    Working knowledge of Communications Platform as a Service (CPaaS) platforms such as Twilio, Amazon Connect, Genesys, or LiveKit. Familiarity with speech technologies including Deepgram, ElevenLabs, Whisper, or OpenAI Realtime APIs.

  • Cloud Infrastructure and DevOps

    Hands-on experience with cloud platform services on Google Cloud Platform (GCP) or Amazon Web Services (AWS). Proficiency in containerization, infrastructure-as-code, deployment pipelines, and cloud-native architectural patterns.

  • Microservices and API Design

    Track record of designing, building, and maintaining RESTful APIs, microservices architectures, and event-driven systems in production environments. Understanding of distributed system tradeoffs, service communication patterns, and data consistency models.

  • Production Operations Mindset

    Deep familiarity with Service Level Agreements (SLAs), observability tools and practices, on-call rotation management, incident response procedures, and rollback strategies. Proven ability to design systems with operability as a first-class concern.

  • AI/LLM Orchestration

    Proficiency using AI coding tools such as GitHub Copilot or similar as a standard part of development workflow, with judgment to review, correct, and own everything that ships. Experience with conversational AI, Large Language Model (LLM) orchestration, and prompt engineering.

Education

  • Computer Science or Related Field

    Bachelor's degree in Computer Science, Software Engineering, Computer Engineering, or equivalent professional software engineering experience demonstrating core computer science fundamentals.

Experience

  • Senior Production System Ownership

    6+ years of professional software engineering experience with demonstrated senior-level ownership of production systems. Track record of designing systems end-to-end, from architecture through deployment, monitoring, and operational excellence.

  • Voice or Realtime Product Development

    Proven experience building or significantly contributing to voice applications, video streaming systems, WebRTC implementations, or other low-latency realtime products. Demonstrates understanding of the unique challenges in realtime systems engineering.

  • Multi-Tenant SaaS Architecture

    Experience designing and implementing multi-tenant systems serving multiple customers or partners. Understanding of isolation models, configuration-driven customization, and the operational complexity of serving diverse customer requirements from a single codebase.

  • Enterprise Security and Compliance

    Experience building compliance and security infrastructure for enterprise customers, including PII redaction, data protection, audit logging, and compliance verification mechanisms. Familiarity with enterprise security requirements and compliance standards.

  • Customer Service Technology

    Bonus experience building customer service platforms, Contact Relationship Management (CRM) systems, contact center technology, or workflow automation tools. Understanding of customer support operational workflows and tooling.

Skills

Required

  • React and TypeScript

    Production-level proficiency in React with TypeScript, including component architecture, state management, performance optimization, and modern frontend development practices.

  • Scala or JVM Languages

    Deep expertise in Scala or alternative JVM languages such as Java or Kotlin. Demonstrated ability to design scalable backend services leveraging JVM ecosystem tools and libraries.

  • Python

    Proficiency in Python for backend service development, data processing, and machine learning integration. Experience with Python frameworks and async programming patterns.

  • Google Cloud Platform (GCP)

    Hands-on experience with Google Cloud Platform services including Compute Engine, Cloud Run, Pub/Sub, Firestore, and GCP networking. Proficiency in infrastructure-as-code tools for GCP.

  • Microservices Architecture

    Deep understanding of microservices design patterns, service-to-service communication, containerization with Docker and Kubernetes, and distributed system considerations.

  • REST APIs and Event-Driven Systems

    Expert-level ability to design and implement RESTful APIs and event-driven architectures. Understanding of API versioning, error handling, and asynchronous messaging patterns.

  • Observability and Monitoring

    Proficiency with observability tooling including distributed tracing, metrics collection, log aggregation, and alerting systems. Ability to instrument systems for production monitoring and debugging.

  • Speech-to-Text and Text-to-Speech Technologies

    Working knowledge of speech recognition and synthesis platforms including Deepgram, ElevenLabs, OpenAI Whisper, or similar technologies. Understanding of streaming audio processing and quality metrics.

Preferred

  • WebRTC and SIP Protocol Experience

    Nice to have

    Experience building applications using WebRTC protocol or Session Initiation Protocol (SIP) for voice communication. Understanding of media streaming, codec selection, and realtime communication challenges.

  • CPaaS Platform Integration

    Nice to have

    Prior experience integrating with Communications Platform as a Service providers such as Twilio, Amazon Connect, Genesys, or LiveKit for voice, video, or messaging capabilities.

  • Large Language Model (LLM) Orchestration

    Nice to have

    Experience building applications with Large Language Models, including prompt engineering, model selection, and orchestration of multiple models in production systems.

  • Travel Industry Technology

    Nice to have

    Familiarity with travel industry systems including Property Management Systems (PMS), Global Distribution Systems (GDS), Computer Reservation Systems (CRS), or travel booking technology stack.

  • AI Coding Tools Proficiency

    Nice to have

    Advanced proficiency with AI-assisted development tools such as GitHub Copilot, demonstrating judgment in review and modification of AI-generated code.

  • Incident Response and On-Call Operations

    Nice to have

    Experience managing on-call rotations, incident command, and post-incident reviews. Demonstrated ability to maintain systems under operational stress and improve through retrospectives.

  • Customer Service Platform Development

    Nice to have

    Background building customer service, Contact Center as a Service (CCaaS), CRM, or workflow automation tooling. Understanding of support operations and customer interaction workflows.

Tech stack

Languages

TypeScriptReactScalaPythonSQL

Frameworks

ReactWebRTCAkka or Play FrameworkFastAPI or Django

Databases

FirestorePostgreSQLRedis

Tools

TwilioAmazon ConnectDeepgramElevenLabsOpenAI Realtime APIDocker and KubernetesGitHub CopilotGoogle Cloud Platform (GCP)

Other

Large Language Models (LLMs)Speech Recognition and SynthesisEvent-Driven ArchitectureDistributed Tracing and ObservabilityPII Redaction and Content Filtering

Compensation

Pay and benefits.

Base·USD 165,000 – 240,000

Full posting

Original listing.

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 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 required

Perks 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 impact

About 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 our fintech products on their sites or powering end-to-end travel portals. Today, our partners include leading travel brands like Capital One, Nubank, Air Canada, and many more.

Here are just a few stats that demonstrate the company's recent growth:

  • Billions of dollars worth of travel and travel fintech are sold through Hopper and HTS' channels every year.

  • Our fintech products, including Cancel for Any Reason and Flight Disruption Assistance, have exceptionally strong CSAT because the terms are always clear, and customers receive instant, no-questions-asked resolutions.

  • Almost 30% of our app customers purchase at least one fintech product when making a booking, and consumers are 1.6x more likely to repurchase if they add fintech to their booking versus if they booked just travel.

  • Given the success of its fintech products, Hopper launched a B2B initiative, HTS (Hopper Technology Solutions), which represents more than 75% of the business.

Through HTS, any travel provider (airlines, hotels, banks, travel agencies, etc.) can integrate and seamlessly distribute Hopper's fintech or travel inventory on their direct channels. As its first HTS partnership, the company partnered with Capital One to co-develop Capital One Travel, a new travel portal designed specifically for cardholders. Other HTS partners include Air Canada, Uber, CommBank, Nubank, Flair Airlines and many more.

Hopper has been named the #1 most innovative company in travel by Fast Company. Hopper has been downloaded over 120 million times and continues to have millions of new installs each month. Hopper is now the #3 largest online travel agency in North America and 70% of our app customers are Gen Z and millennial travelers.

Hopper has raised over $750 million USD of private capital and is backed by some of the largest institutional investors and banks in the world. HTS is primed to continue its growth as the leading travel ecommerce provider in a $1 trillion online shopping category. The Hopper app and website will also continue to be the preferred travel provider for Gen Z and Millennials.

Come take off with us!

#LI-Remote

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