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Principal Full Stack Developer (.NET/React)

Sparq

Remote · Costa RicaFull Time
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Principal Full Stack Developer (.NET/React) at Sparq is a full time role based in Remote · Costa Rica (remote). It was published on 3 September 2026 and was open at last check.

Principal Full Stack Developer (.NET/React) at Sparq — key details
RolePrincipal Full Stack Developer (.NET/React)
CompanySparq
LocationRemote · Costa Rica (remote)
Employment typeFull Time
Published3 September 2026
StatusOpen at last check

At Sparq, we help companies solve the right problems—not just build more technology.

We’re a modern product engineering partner blending strategy, craftsmanship, and speed to help organizations modernize confidently in the age of AI. From data ecosystems to digital products and AI acceleration, we turn complexity into clarity and ideas into impact.

If you’re driven to build what’s next, lead with empathy, and deliver excellence without ego, you’ll feel right at home at Sparq.

C2C is not available

Must be authorized to work in the U.S. without sponsorship

Why you will enjoy Mondays again:

  • Opportunity to work alongside a talented, diverse team in a collaborative and creative environment
  • Ongoing investment in your growth through training, mentorship, and industry certifications
  • Hands-on exposure to cutting-edge technologies across multiple industries
  • Recognition programs and employee awards within an inclusive culture that celebrates great work, including our AI Innovators Program
  • Remote or hybrid work options

A Day in the Life:

We are seeking a Principal Full Stack Developer with deep expertise in React and strong experience in .NET/C# to lead the design and delivery of scalable, high-performing web applications. This role emphasizes front-end leadership with React, while also leveraging the Microsoft technology stack for robust back-end solutions. The ideal candidate combines hands-on technical excellence with the ability to drive architectural decisions, mentor developers, and collaborate with stakeholders to deliver enterprise-grade applications.

  • Architect and lead front-end development using React, ensuring high performance, responsive design, and maintainability at scale.
  • Design, build, and optimize full-stack solutions with C#, .NET Core, ASP.NET, SQL Server, Web API, and MVC.
  • Leverage AWS services to design, deploy, and scale cloud-based infrastructure supporting enterprise-grade applications.
  • Establish front-end standards and best practices, guiding teams in component architecture, state management, and UI/UX alignment.
  • Provide technical leadership and mentorship, fostering growth across development teams and promoting engineering excellence.
  • Partner with Product, UX, QA, and DevOps teams to translate business requirements into scalable and user-friendly applications.
  • Lead code reviews and enforce standards for both React and .NET projects to ensure high-quality, consistent deliverables.
  • Actively use AI tools, including Claude through our Anthropic partnership, to streamline tasks, improve the quality of your work, and share best practices with teammates while continuously seeking new ways to integrate AI into your everyday workflows
  • Enhance existing products by building new functionality while maintaining stability and backward compatibility.
  • Champion modern software development practices, including CI/CD pipelines, automated testing, and cloud-ready architectures.
  • Drive technology evaluations, particularly in the JavaScript/TypeScript and React ecosystem, recommending tools and frameworks to enhance front-end capabilities.
  • Own the end-to-end SDLC, ensuring timely delivery of reliable, scalable, and performant software solutions.

What it takes:

  • Consultative approach and problem solving skills to successfully align digital solutions with long-term business goals of the client
  • Hands-on experience using AI tools to enhance daily work, or a strong desire to do so, including a willingness to experiment, learn, and champion AI adoption within your role
  • Claude Certified Developer or Architect highly preferred; possible opportunity to obtain as a Sparq colleague
  • Commitment to understanding and exceeding client expectations
  • Ability to perform project oversight and execution of deliverables
  • Flexibility to adapt within a high-growth organization
  • Ability to lead, mentor and motivate those around them
  • Hunger for continuous learning and professional development
  • Intellectual curiosity to provide creative solutions
  • Full understanding of the software development life cycle
  • Ability to positively impact fellow colleagues through effective leadership, presentations, coaching, etc.
  • Desire to work in a team environment
  • Good interpersonal, written and verbal communication skills

Regardless of your specific role, we seek individuals who are excited to explore, adopt, and evangelize AI tools and methodologies. If you have experience in AI or a proven track record of rapidly learning and mentoring others on emerging tech, you’ll fit right in.

Equal Employment Opportunity Policy: Sparq is proud to offer equal employment opportunity without regard to age, color, disability, gender, gender identity, genetic information, marital status, military status, national origin, race, religion, sexual orientation, veteran status, or any other legally protected characteristic.

We are committed to providing equal employment opportunities and believe in an inclusive workplace. If you require reasonable accommodations to participate in the job application or interview process, please let us know by contacting

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Principal Full Stack Developer (.NET/React) at Sparq — questions answered

What does the Principal Full Stack Developer (.NET/React) role at Sparq pay?

Sparq does not publish a salary on this Principal Full Stack Developer (.NET/React) listing, so OnJob shows no figure for it rather than an estimate. For what this role pays across the market, the OnJob salary guides aggregate the live listings that do disclose pay.

Is the Principal Full Stack Developer (.NET/React) role at Sparq remote?

Yes — Sparq advertises this Principal Full Stack Developer (.NET/React) role as remote, tied to Remote · Costa Rica, and it is listed as full time work. Remote terms come from the employer's own posting, so confirm the expected working hours, timezone and any on-site days with Sparq before you apply.

Is the Principal Full Stack Developer (.NET/React) role at Sparq still open?

The Principal Full Stack Developer (.NET/React) posting at Sparq was open at OnJob's last check of the employer's careers page, having been published on 3 September 2026. OnJob re-checks source listings on each build and marks a role closed once it disappears, but listings can close without notice, so the employer's own page is the final word.

How do you apply for the Principal Full Stack Developer (.NET/React) role at Sparq?

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