Senior Fullstack Engineer - Focus SDKs (f/m/d)

About the Opportunity

Become part of the Ninetailed Team, pioneer of composable personalization and experimentation within the Contentful family.

Join Ninetailed by Contentful as a Senior Fullstack Engineer and shape the future of how digital personalized user experiences are being built at scale.

You’ll play a key role in developing SDKs and tools that empower developers to seamlessly integrate our platform. Your work will directly impact the developer experience for major companies around the world.

What to expect?

• Develop and maintain SDKs and tools that are both high-performing and enjoyable for developers to use.
• Own the strategic future of the Ninetailed SDKs and its architecture.
• Collaborate closely with API teams to implement efficient protocols to exchange events and render dynamic experiences in the most performant way possible.
• Ensure stability & reliability through a great suite of unit and e2e tests
• Make the life of your peers and external users joyful by creating strong documentation.
• Manage the release process for public packages using semantic versioning, ensuring smooth transitions and upgrades for developers.
• Optimize for performance by focusing on reducing bundle sizes and improving load times.
• Work with external engineers on different flavors of our SDKs to enable customers to use Ninetailed with mobile platforms.

What you need to be successful

• Proven experience building developer-facing tools, libraries, or open-source projects.
• Strong experience with TypeScript, including deep understanding of its type system.
• Proficient in using React and some of its higher level frameworks (e.g. Next.js, Remix, Astro etc.) and other similar libraries (e.

g. Vue, Angular, Svelte, Nuxt.js) for front-end development.

• Hands-on experience with modern bundlers such as Rollup, Vite, etc.
• Solid background in automated testing, including both unit and e2e tests, using frameworks like Jest & Playwright.
• Experience working with Web APIs and ensuring browser compatibility.
• Experience in optimizing for bundle size and load time.
• Familiarity with semantic versioning for managing public package releases.
• Experience with Monorepos for handling multiple packages, ideally nx.dev is a plus.
• Knowledge in mobile development (e.g. React Native) is great to have.
• Strong collaborative mindset with experience working cross-functionally.
• Great communication skills in English, especially when explaining complex technical concepts.

What's in it for You?

• Join an ambitious tech company reshaping the way people build digital experiences
• Full-time employees receive Stock Options for the opportunity to share in the success of our company
• Fertility and family-building benefits, including a lifetime reimbursable wallet to support your growing family.
• We value Work-Life balance and You Time! A generous amount of paid time off, including vacation days,compassion days for loss, education days, and volunteer days
• Use your personal annual education budget to improve your skills and grow in your career
• Enjoy a full range of virtual and in-person events, including workshops, guest speakers, and fun team activities, supporting learning and networking exchange beyond the usual work duties
• An annual wellbeing stipend to care for your physical, financial, or emotional health
• A monthly communication stipend and phone hardware upgrade reimbursement
• New hire office equipment stipend for hybrid or distributed employees. Get the gear you need to work at your best.

LI-Hybrid