Senior Full Stack Engineer (Realtime & Voice) Customer Experience Platform
Full Stack Engineer · Senior · Full Time · Remote
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Role
What you'll do.
Senior Full Stack Engineer specializing in realtime voice and chat systems for Hopper's HTS Assist, an agentic AI assistant transforming travel customer service. You will own the voice channel end-to-end, architecting telephony integrations, streaming speech-to-text/text-to-speech pipelines, and realtime LLM orchestration while building React/TypeScript frontends, Scala/Python backends, and GCP infrastructure for enterprise travel partners. This is a high-impact, lean-team role where you'll work across the full technology stack, shipping features that directly reach millions of travelers globally.
Responsibilities
- End-to-End Voice Channel Ownership: Own the complete voice infrastructure stack including telephony and Communications Platform as a Service (CPaaS) integrations with providers like Twilio and Amazon Connect. Architect and maintain streaming speech-to-text and text-to-speech pipelines, implement realtime model orchestration, and establish latency and quality budgets to ensure enterprise-grade performance for travel service conversations.
- Full-Stack Feature Development: Build and ship product features across all layers: React/TypeScript web chat frontends for intuitive customer interactions, backend services in Scala and Python for business logic and API layers, and infrastructure-as-code on Google Cloud Platform. Ensure consistent quality and architecture across frontend, backend, and infrastructure components.
- Multi-Tenant Platform Architecture: Design scalable systems that serve multiple enterprise travel partners through configuration-driven approaches rather than code forks. Implement tenant isolation, feature flagging, and deployment strategies that allow rapid onboarding of partners like Capital One, Air Canada, and CommBank while maintaining system stability and performance.
- Safety, Compliance, and Enterprise Security: Build security and compliance infrastructure that enterprise partners audit and require, including guardrails for AI-generated responses, content filtering to prevent harmful outputs, and PII redaction mechanisms. Implement integration points for regulatory compliance across multiple jurisdictions where travel partners operate.
- Production Systems Reliability: Maintain revenue-critical deployments through comprehensive observability, alerting strategies, incident response protocols, and SLA performance tracking. Own on-call rotations, develop runbooks for common failures, and establish rollback procedures. Monitor system health across realtime voice, chat, and backend services serving millions of travelers.
- Partner Integration Enablement: Build platform capabilities and abstractions that forward-deployed engineers use to configure CPaaS integrations and execute go-lives with travel partners. Create clear documentation, SDKs, and tooling that reduces friction in partner onboarding and enables rapid deployment of new customer service channels.
- Engineering Excellence and Mentorship: Raise the engineering bar through rigorous code reviews focusing on correctness and maintainability, architecture reviews evaluating system design decisions, and hands-on mentoring of team members. Share knowledge about realtime systems, voice technologies, and production-grade engineering practices to build team capability.
Qualifications
What we look for.
Technical
Realtime Systems Architecture
Demonstrated hands-on experience building low-latency, realtime products such as voice applications, WebRTC/SIP implementations, streaming media systems, or comparable systems where millisecond-level performance is critical. Understanding of timing constraints, buffer management, and real-time concurrency patterns.
Frontend Development Expertise
Strong production experience with modern frontend frameworks, specifically React and TypeScript. Proficiency in component architecture, state management, asynchronous data handling, and performance optimization for web applications serving enterprise customers.
Backend Development Depth
Production-level expertise in either Scala or another JVM language, combined with fluency in Python. Ability to design and implement scalable microservices, handle concurrent request processing, implement async/reactive patterns, and optimize for throughput and latency.
Cloud Infrastructure on GCP or AWS
Hands-on experience provisioning, configuring, and maintaining cloud infrastructure on Google Cloud Platform or Amazon Web Services. Proficiency with infrastructure-as-code tools, containerization strategies, Kubernetes orchestration, networking, and observability solutions in cloud environments.
RESTful APIs and Distributed Systems
Track record designing, building, and maintaining RESTful APIs, microservices architectures, or event-driven systems at scale. Understanding of service boundaries, inter-service communication patterns, eventual consistency models, and distributed tracing for debugging complex interactions.
AI/ML Tooling and LLM Integration
Familiarity with AI coding assistants and AI/ML development workflows as standard practice, combined with judgment to review, validate, and take ownership of AI-generated code. Experience integrating large language models, managing prompt engineering, and implementing safeguards for AI-generated customer-facing content.
Observability and Operational Excellence
Deep understanding of production systems monitoring through logs, metrics, and distributed tracing. Experience setting and meeting SLAs, designing alerting strategies, managing on-call rotations, implementing rollback procedures, and conducting incident post-mortems to drive continuous improvement.
Education
Computer Science or Related Field (Preferred)
Bachelor's degree in Computer Science, Software Engineering, Computer Engineering, or related discipline. Alternatively, equivalent professional experience demonstrating systems thinking, software design patterns, and deep technical capability.
Experience
Senior-Level Production Ownership
Minimum 6+ years of software engineering experience with demonstrated senior-level ownership of production systems. Experience making architectural decisions, leading technical initiatives from design through deployment, and taking responsibility for system reliability and performance at scale.
Full-Stack Product Development
Proven ability to work across the entire stack from browser APIs and frontend frameworks through backend services, databases, and infrastructure. Track record shipping complete features end-to-end rather than specializing exclusively in one layer.
Conversational AI and LLM Orchestration (Preferred)
Experience building or maintaining conversational AI systems, chatbots, or voice applications using modern large language models. Familiarity with LLM orchestration frameworks, prompt chaining, retrieval-augmented generation (RAG), and managing token usage/latency in real-time applications.
Speech Technologies (Preferred)
Working knowledge of speech-to-text and text-to-speech technologies such as Deepgram, ElevenLabs, OpenAI Whisper, or OpenAI Realtime API. Understanding of audio processing pipelines, model latency characteristics, and quality metrics for speech recognition and synthesis.
CPaaS and Telephony Platforms (Preferred)
Working knowledge of Communications Platform as a Service providers such as Twilio, Amazon Connect, Genesys, or LiveKit. Experience integrating voice channels, managing call flows, implementing IVR systems, or building communication-centric applications.
Customer Service and CX Systems (Preferred)
Background building customer service platforms, CRM systems, contact center solutions, or workflow automation tools. Understanding of enterprise customer service requirements, multi-channel communication patterns, and customer interaction workflows at scale.
Skills
Required
React
Production expertise building component-based user interfaces with React, including hooks, context API or Redux state management, and performance optimization techniques for customer-facing applications.
TypeScript
Advanced TypeScript proficiency for building type-safe frontend applications, understanding generics, advanced type inference, and leveraging TypeScript for developer productivity and code maintainability.
Scala or JVM Languages
Production-level expertise in Scala or equivalent JVM language (Java, Kotlin) for building backend services, understanding functional programming patterns, concurrent programming, and performance tuning on the JVM.
Python
Production Python experience building scalable backend services, API implementations, data processing pipelines, or machine learning inference systems. Proficiency with async frameworks and production deployment patterns.
Google Cloud Platform (GCP)
Hands-on experience with GCP services including Compute Engine, Cloud Run, Cloud Storage, Pub/Sub, BigQuery, and Cloud Logging. Ability to architect and deploy applications on GCP with appropriate security, scaling, and observability patterns.
Microservices Architecture
Design and implementation experience with microservices-based systems, including service decomposition, inter-service communication patterns (REST, gRPC, message queues), and managing distributed transactions.
API Design and Implementation
Expertise designing and implementing RESTful APIs with proper versioning, error handling, authentication/authorization, rate limiting, and documentation. Understanding of API-first architecture and developer experience.
Realtime Systems and Streaming
Experience with realtime data processing, event streaming platforms, websockets, or reactive programming patterns. Understanding of backpressure handling, buffering strategies, and latency-sensitive system design.
Distributed Systems Debugging
Proficiency with observability tools including application performance monitoring, distributed tracing (OpenTelemetry, Jaeger), structured logging, and metrics collection. Ability to diagnose complex issues across multiple services.
Preferred
WebRTC and SIP Protocols
Nice to haveFamiliarity with WebRTC for peer-to-peer communication or Session Initiation Protocol (SIP) for VoIP implementations. Understanding of audio codec selection, network traversal (STUN/TURN), and real-time media transport.
Speech Recognition (STT) Technologies
Nice to haveExperience integrating speech-to-text services from providers like OpenAI Whisper, Deepgram, Google Cloud Speech-to-Text, or AWS Transcribe. Understanding of audio preprocessing, model selection based on language/accent/domain, and handling streaming audio.
Text-to-Speech (TTS) Services
Nice to haveExperience with text-to-speech platforms like ElevenLabs, AWS Polly, Google Cloud Text-to-Speech, or OpenAI TTS. Knowledge of voice selection, prosody control, real-time streaming synthesis, and latency optimization.
LLM Orchestration Frameworks
Nice to haveWorking knowledge of LLM orchestration platforms like LangChain, LlamaIndex, or OpenAI's API ecosystem. Experience building multi-step reasoning chains, managing context windows, and implementing cost-effective inference patterns.
Twilio Integration
Nice to haveExperience building communication applications with Twilio, including programmable voice, SMS, or video capabilities. Understanding of Twilio webhooks, SIP trunks, and managed telephony integration patterns.
Amazon Connect
Nice to haveExperience with AWS Amazon Connect for building contact center solutions, including call routing, IVR flows, and integration with backend services through Connect Lambda functions or streaming transcripts.
Kubernetes and Container Orchestration
Nice to haveProduction experience deploying and managing applications on Kubernetes, including resource definitions, health checks, scaling policies, and debugging container runtime issues.
Database Design for Scale
Nice to haveExperience with both SQL databases (PostgreSQL, Cloud SQL) and NoSQL datastores (Firestore, Datastore), understanding trade-offs between consistency/availability, query optimization, and scaling patterns.
Travel Industry Systems
Nice to haveFamiliarity with travel technology ecosystems including Global Distribution Systems (GDS), Property Management Systems (PMS), Central Reservation Systems (CRS), or airline Passenger Service Systems (PSS).
Content Moderation and PII Detection
Nice to haveExperience implementing content filtering, personally identifiable information (PII) detection/redaction, or data classification systems for regulatory compliance in customer-facing applications.
AI Coding Tools
Nice to haveRegular use of AI-assisted development tools like GitHub Copilot, Claude, or ChatGPT in production workflows, with demonstrated ability to review, validate, and improve AI-generated code.
Compensation
Pay and benefits.
Base·USD 140,000 – 200,000
Full posting
Original listing.
Note on Contractual Status 🇮🇪: This position is offered as an Independent Contractor engagement (Contract for Services) and does not constitute an offer of direct employment. The successful candidate will operate as a self-employed individual or through a Personal Service Company (PSC). You will be responsible for your own tax, PRSI, and VAT compliance in accordance with Irish Revenue Commissioners regulations. Engagement is contingent upon providing proof of valid business registration and appropriate professional indemnity insurance.
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 and the upsides of pre-IPO equity packages
Carrot Cash travel stipend
FlexDesk All Access Pass and work-from-home stipend
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!
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