Senior Software Engineer (Fullstack) - Product (Lisbon)

At Datadog, fullstack engineers build the end-to-end product experiences that power our observability platform. As a Senior Fullstack Engineer with a frontend focus, you’ll drive complex, user-facing features while contributing to the backend systems that support them. You’ll architect performant interfaces at scale, collaborating across disciplines to create seamless product experiences. This role is ideal for engineers who excel in frontend-led fullstack development and want to have deep ownership over product surfaces that impact customers directly.

At Datadog, we place value in our office culture - the relationships and collaboration it builds and the creativity it brings to the table. We operate as a hybrid workplace to ensure our Datadogs can create a work-life harmony that best fits them.

Disclaimer: This is not a strict 50/50 frontend–backend split. The exact balance varies by team, project, and product area, and may shift over time. You’ll regularly contribute across the stack, but the role is designed for engineers who prefer and excel at frontend-led fullstack work.

At Datadog, we place value in our office culture - the relationships that it builds, the creativity it brings to the table, and the collaboration of being together. We operate as a hybrid workplace to ensure our employees can create a work-life harmony that best fits them.

What You’ll Do: 

• Architect, build, and ship end-to-end product features—owning everything from frontend UI to backend logic, data modeling, and API design


• Drive technical excellence for the frontend experience, including performance, accessibility, responsiveness, and overall quality


• Collaborate with product managers, designers, and backend engineers to define user experiences, data flows, and APIs


• Improve the reliability and scalability of services that support your features, contributing backend code where needed


• Lead technical discussions, influence architecture decisions, and mentor other engineers on fullstack patterns and best practices


• Ensure strong testing coverage, clear documentation, and long-term maintainability across the stack

Who You Are:

• You have 6+ years of experience building and shipping production-grade fullstack features at scale


• Deep expertise in JavaScript/TypeScript and modern frontend frameworks (React preferred)


• Solid backend engineering skills with proficiency in at least one server-side language (e.g., Python, Go, Java) and familiarity with APIs, databases, and distributed systems


• Ability to interpret broad product requirements and translate them into polished, user-facing applications


• Strong understanding of frontend architecture, state management, performance tuning, and client-server interaction patterns


• Excellent communicator with the ability to lead design and architecture discussions in a collaborative, cross-functional environment

Datadog values people from all walks of life. We understand not everyone will meet all the above qualifications on day one. That's okay. If you’re passionate about technology and want to grow your skills, we encourage you to apply. 

Benefits and Growth: 

• Generous and competitive benefits package


• New hire stock equity (RSUs) and employee stock purchase plan


• Continuous career development and pathing opportunities


• Employee-focused best in class onboarding


• Internal mentor and cross-departmental buddy program


• Friendly and inclusive workplace culture

Benefits and Growth listed above may vary based on the country of your employment and the nature of your employment with Datadog.