First Line Software works with some of the world's top businesses and organizations in industries like healthcare, data engineering, warehouse automation, retail digitalization, mobile app development, and e-commerce. Our projects are as varied as our people, and our people are as talented as they come. We prefer working as a transparent and supportive team, who shares our knowledge as well as our success.

Let's see what we can create together!

The project and your role Our client is rebuilding its guest-facing digital estate on a modern microservices architecture moving away from a fragmented collection of out-of-the-box portals toward a purpose-built digital platform that delivers personalised, seamless guest experiences across discovery, booking, pre-stay, and in-stay touchpoints. As a Digital Product Engineer, you'll build the digital products guests and staff use every day, working on a React/Next.js front-end and a back-end of independently deployable .NET 8 / ASP.NET Core microservices hosted on AWS.

Build and maintain guest-facing features in React and Next.js — search, the booking funnel, conversion optimisation, and promotional campaign delivery, in partnership with commercial and marketing teams

Deliver logged-in guest journeys on the guest portal, including pre-stay upsell, activity booking, and in-stay engagement

Contribute to loyalty platform features — enrolment flows, member personalisation, and loyalty mechanics

Design and build .NET 8 / ASP.NET Core microservices — REST APIs, domain logic, and integrations with core booking, CMS, and contact-center systems

Deploy and operate microservices on AWS using Lambda and ECS/Fargate, choosing the right hosting model per service





Implement event-driven communication between services using AWS SQS, SNS, and EventBridge

Design RESTful APIs to agreed standards, including OpenAPI specifications, versioning, and documentation

Write unit, integration, and end-to-end tests, and ship through CI/CD (GitHub Actions)

Participate in code reviews with nearshore engineering partners and take ownership of your services in production, including incident response

2+ years of software engineering experience spanning front-end and back-end development

Hands-on, production experience with React and Next.js — App Router, server components, SSR/SSG

Hands-on, production experience with .NET (Core/.NET 5+) and C#; .NET 8 / ASP.NET Core strongly preferred

TypeScript across the stack

Demonstrable experience building and deploying microservices on AWS (Lambda and/or ECS/Fargate)

Experience with RESTful API design in a microservices architecture

Experience working in agile sprint teams, ideally alongside nearshore or offshore engineering partners

Consumer-facing product experience — eCommerce, hospitality, travel, or retail preferred

English language proficiency for technical documentation and team communication

Nice to have:

Experience integrating LLMs or conversational AI (OpenAI API or equivalent)

WhatsApp Business API or Amazon Connect experience

Familiarity with hospitality CRS/PMS systems

What we can offer

Our modern stack projects are the right mix of exciting and challenging

Gain access to our diverse range of training programs, courses, and certifications

Choose your work style — this role is hybrid, with 3 days a week in the office

Enhance your language skills with our corporate English classes

Work from anywhere and explore the world with our Workation program

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📌 Digital Product Engineer (Madrid)
🏢 First Line Software
📍 Madrid