# FullStack Developper

> Cryptonext Security · Paris, France (Hybrid) · Full-time · Posted 2026-03-30

**Workplace:** hybrid

**Department:** Research & Development

## Description

**Who we are**

CryptoNext Security is a deeptech startup specializing in post-quantum cryptography. Our solutions help businesses and institutions prepare for a future where quantum computers will challenge traditional data security. We work with leading clients in finance, defense, and telecommunications.

**On a daily basis, you will**

-   Design and develop **React-based** user interfaces for our post quantum cryptography products.
-   Collaborate with **Product** and **Backend** teams to ensure a smooth and intuitive user experience.
-   Optimize performance and ensure **cross-browser and cross-device compatibility**.
-   Integrate **REST APIs** to interact with our backend services.
-   Participate in **code reviews** and apply best practices (unit testing, continuous integration, documentation).
-   Contribute to frontend architecture improvements by suggesting **technological upgrades and refactorings**.
-   Enable improvement of our products even if outside of your common scope
-   Embrace our frontend team work principles: “Done over perfect” / we ship/deliver fast: KISS, DRY (don’t repeat yourself), SOLID

## Requirements

**The skills you'll need**

-   **Strong expertise in React** / Next.js and its ecosystem (React Hooks, Context API).
-   Excellent knowledge of **TypeScript** and robust programming principles.
-   Experience with **modern UI libraries** (Tailwind, or chadcn/ui).
-   Experience integrating **REST APIs**
-   Good grasp of **frontend performance optimization** and related tools (Webpack, Vite, CoreWebVitals).
-   Experience with **frontend testing frameworks** (Jest, React Testing Library, Cypress).
-   Familiarity with **Git, CI/CD pipelines, and DevOps** for automated integration and deployment.

**Bonus skills**

-   **gRPC**.
-   Knowledge of **secure coding practices** and application security.
-   Basic understanding of **cryptography and cybersecurity**.
-   Experience in a **startup or deeptech environment**.

## Benefits

**The team you'll be joining**

You will be part of our **R&D team**, working closely with backend developers, the product team, and UX/UI designers. You will report to the  and collaborate with other departments to build high-performance, user-friendly interfaces tailored to our clients’ needs.

**Our recruitment process**

1.  **Initial discussion** with our HR team to explore your background and motivations.
2.  **Technical interview** with a developer, including a coding test.
3.  **Meeting with a manager** to ensure alignment with our company culture.
4.  If successful, you’ll receive a final offer! 🚀

**What’s in it for you at CryptoNext**

-   A **stimulating work environment** with cutting-edge technological challenges.
-   A fast-growing startup with a team of passionate professionals.
-   **Flexible remote work options** and an office in **Paris**.
-   A **competitive salary**, aligned with our compensation philosophy.
-   A deep dive into the exciting world of **post-quantum cryptography** and cybersecurity.

Ready to join the adventure? 🚀 **Apply now!**

## Apply

[Apply at Cryptonext Security](https://apply.workable.com/cryptonext-security/j/04E99EB329/apply)

---
Powered by [Workable](https://www.workable.com)