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

Hopper; Madrid; Presencial; EUR 120.000 - 170.000; Jornada completa

Ventajas ofrecidas por este puesto de trabajo

Private medical and dental coverage

Private life and accident coverage

Generous parental leave

FlexDesk coworking & WFH stipend

Unlimited PTO

Gym membership stipend

Carrot Cash travel stipend

Equity / pre-IPO upside

Open communication culture

Small, dynamic teams

Descripción de la vacante

Hopper is seeking a senior full stack engineer to anchor HTS Assist, our agentic AI assistant for travel. You will own the realtime and voice layer end to end, building React/TypeScript front ends, Scala/Python services, and cloud infrastructure.

The ideal candidate has 6+ years of experience and a track record with realtime/low-latency systems, RESTful APIs, and multi-tenant architectures. You will contribute to safety, observability, and partner integrations, while mentoring others in a fast,

Formación

• 6+ years of software engineering with senior ownership of production systems.
• Hands-on realtime voice applications or low-latency tech experience.
• Strong React/TypeScript frontend and backend in Scala or Python, with cloud infra on GCP/AWS.
• Experience designing RESTful APIs, microservices or event-driven systems.

Responsabilidades

• Own the voice channel end to end, including telephony integrations and streaming pipelines.
• Build features across the stack: React/TypeScript frontend, Scala/Python backend, and cloud infra.
• Design for multi-tenant scale with a single codebase configured for partners.
• Develop safety, compliance, guardrails, and PII redaction integration points.
• Maintain deployments with observability, alerts, incident response, and SLAs.
• Configure platform capabilities for partner telephony integrations and go-lives.
• Raise engineering bar via code reviews, architecture reviews, and mentoring.

Conocimientos

Senior software engineering

Realtime/low-latency systems

React/TypeScript

Scala/Python backend

RESTful APIs / microservices

AI coding tools familiarity

Observability & SRE mindset

Herramientas

Twilio

Amazon Connect

CPaaS platforms

WebRTC

Descripción del empleo

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 the cost of employee premiums for private medical and dental coverage


• Hopper also offers private life and accident coverage


• 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


• Unlimited PTO


• Hopper offers a monthly cash allowance for gym memberships and to cover home office expenses for a comfortable remote working experience


• Carrot Cash travel 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.

• 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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