Senior Backend Engineer, MCP, RAG and Fine-Tuning (100% Remote)

Company: Hopper
Location: Boston
Posted on: April 2, 2026

Job Description:

About the job Did you know Hopper's technology powers some of the largest travel portals in the world? Our Hopper Technology Solutions (HTS) platform drives travel purchases for major global brands — from banks to airlines to fintech leaders. This platform is essentially a configurable, multi-tenant travel commerce engine, enabling partners to launch world-class hotel and travel booking experiences faster, with less custom engineering. We’re looking for a senior software engineer who has adopted the best practices in terms of AI-assisted coding. You are not using AI to auto-complete your code; you are using multiple agents to autonomously deliver features at a speed that was impossible a few months ago. You understand well the strengths and weaknesses of LLMs, and you know how to build a feedback loop and guardrails to get the best out of them. Tech stack Our backend systems are written in Scala, and we use a suite of GCP services Our frontends are web apps using react typescript What your day-to-day would look like Identify and execute improvements to the code base to allow agents to go faster and safer. Work with a group of top-tier engineers in a low-process environment powered by trust and high autonomy. Drive decisions and consensus asynchronously by leveraging AI to author the thoughtful documentation and specifications that guide the team. Ship fast. Learn fast. Repeat. Orchestrate AI agents to build new features from top to bottom, from UX to database, with minimal oversight. Architect the scalable solutions and foundational patterns that allow us to efficiently launch new portals. Proven experience training, deploying and iteratively optimizing LLMs to power complex product features. Work directly with PMs and business partners to define and refine our roadmap; your voice and technical vision matter. Collaborate with a diverse group of people, giving and receiving the high-level feedback necessary for growth. An ideal candidate has A natural drive to fearlessly deep dive into an unknown code base while keeping their eyes on the goal to deliver results fast. Proven ability to direct AI agents and automated workflows to architect, implement, and maintain complex software systems with minimal human intervention. Expertise in designing the technical guardrails and automated feedback loops that maximize the productivity and reliability of AI agents operating within the codebase. Strong product thinking where your conception of quality and architecture is inherently anchored in the customer experience. Experience with, or a mastery-level willingness to learn, distributed system development in Scala. 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. Unlimited PTO. Carrot Cash travel stipend. Access to co-working space on demand through FlexDesk AND Work-from-home stipend. Please ask us about our very generous parental leave, much above industry standards!. Entrepreneurial culture where pushing limits and taking risks is everyday business. Open communication with management and company leadership. Small, dynamic teams = massive impact. 100% employer paid Medical, Dental and Vision coverage for employees. Access to Disability & Life insurance. Health Reimbursement Account (HRA). DCA/ FSA and access to 401k plan. More 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. he 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 vs 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 agencies in North America and 70% of our app customers are Gen-Z and millennials 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

Keywords: Hopper, Concord , Senior Backend Engineer, MCP, RAG and Fine-Tuning (100% Remote), IT / Software / Systems , Boston, New Hampshire