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Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md). --- # Staff Full-Stack Software Engineer - **Company:** X4 Life Sciences - **Location:** Washington, DC, United States - **Experience:** Expert - **Contract:** Permanent contract - **Skills:** JavaScript (Programming Language), Application Programming Interfaces (APIs), Artificial Intelligence, Amazon Web Services, Amazon Elastic Compute Cloud, Amazon S3, Application Integration Architecture, Application Performance Management, Computing Platforms, Microsoft Azure, Cloud Computing, Cloud Engineering, Code Review, Collaborative Software, Databases, Amazon DynamoDB, Github, Python (Programming Language), PostgreSQL, Machine Learning, Node.Js, NoSQL, Software Architecture, OpenAI, Next.js, Software Engineering, Systems Architecture, TypeScript, AWS Cdk, Pulumi, Bitbucket Pipelines, ReactJS, Retrieval-Augmented Generation, Open-source Models, Large Language Models, Prompt Engineering, Reliability of Systems, Backend, Agentic-AI, Fastapi, Amazon Relational Database Service, Kubernetes, Atlassian Tools, Bitbucket, Graphql, Front End Software Development, Functional Programming, Google Gemini, Terraform, Software Version Control - **Published:** October 20, 2026 - **Apply:** https://www.juju.com/job/2_166794239 ## About the Role * 8+ years of professional software engineering experience, with a strong background in full-stack development and customer-facing applications. * Extensive experience with JavaScript/TypeScript and modern front-end frameworks, particularly React, Next.js or TanStack. * Strong server-side development experience with Node.js and Python, ideally including FastAPI. * Proven experience designing and evolving scalable software architectures, with the ability to make sound technical decisions across the full stack. * Hands-on cloud engineering experience with AWS and/or Azure, including services such as EC2, Kubernetes, Lambda, S3 and RDS, or their Azure equivalents. * Strong experience building secure, scalable REST and GraphQL APIs. * Experience working with relational and NoSQL databases, including PostgreSQL, DynamoDB or similar technologies. * Practical experience integrating LLM APIs into production applications, with an understanding of prompt engineering, RAG, agent-based workflows and context window management. * Experience with version control and engineering collaboration tools such as GitHub, Bitbucket, Jira and Confluence. * The ability to take ownership of complex technical challenges, balance short-term delivery with long-term architecture and operate effectively in a fast-moving environment. Desirable Experience * Experience designing and maintaining CI/CD pipelines using GitHub Actions, Bitbucket Pipelines or similar tools. * Strong knowledge of Infrastructure as Code, including Terraform, Pulumi or AWS CDK. * Previous experience in healthtech or another regulated or data-sensitive environment, particularly working with protected health information (PHI). * Experience building AI-powered products or introducing LLM capabilities into established software platforms. * A background in a startup or scale-up where you've helped evolve architecture, establish engineering practices and support rapid product growth. xrbllit ## Description X4 are working with a fast-growing healthtech company that's building innovative technology to transform how digital healthcare services are delivered. With a strong focus on scalable software and AI-driven solutions, the business is continuing to invest in its engineering capabilities as it expands its platform and develops new products. This is an opportunity to join a growing technology team where you'll have real influence over architectural decisions, product development and the wider engineering roadmap. As a Staff Full-Stack Software Engineer, you'll work across front-end, back-end, cloud infrastructure and AI integration, helping build reliable, secure and scalable applications while setting technical standards for the wider team. You'll combine hands-on engineering with technical leadership, working closely with product and engineering colleagues to turn ambitious ideas into production-ready solutions., * Lead the design and development of scalable, customer-facing applications, taking ownership of technical decisions from initial design through to production. * Develop and evolve front-end applications using React, Next.js and modern JavaScript/TypeScript frameworks. * Design and maintain back-end services, APIs and system architecture using Node.js and Python, including FastAPI. * Own architectural decisions across AWS and/or Azure infrastructure, ensuring services are secure, reliable and built to scale. * Drive improvements to CI/CD pipelines, deployment processes and infrastructure automation, promoting consistent engineering practices. * Lead the integration of large language models (LLMs) and machine learning capabilities into production applications, using providers such as OpenAI, Anthropic, Gemini and open-source models. * Design robust REST and GraphQL APIs and establish best practices around performance, security, maintainability and system reliability. * Make informed decisions around database architecture, data modelling and application performance across relational and NoSQL technologies. * Work closely with product management to translate business requirements into technical solutions and influence the platform's technical roadmap. * Provide technical guidance to other engineers through code reviews, design discussions and knowledge sharing, helping raise engineering standards across the team.