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- Tasks: Lead the development of a secure, intuitive encrypted email app using React Native.
- Company: Join an ambitious start-up revolutionising secure communication technology.
- Benefits: Competitive salary, flexible work environment, and opportunities for professional growth.
- Why this job: Make a real impact on how millions communicate securely with cutting-edge technology.
- Qualifications: Extensive experience in React Native and automated testing; startup experience preferred.
- Other info: Dynamic team culture with opportunities to innovate and grow your career.
The predicted salary is between 48000 - 72000 £ per year.
Certonymity is developing the next generation of secure communication technology. Our mission is to make encrypted email simple and widely accessible by combining advanced cryptography with real-world identity verification. Our first product, C.Email, enables users to send and receive fully end-to-end encrypted messages without depending on third parties or complicated configurations. Each user has a verified digital identity, connected to their passport yet kept completely private through cryptographic keys — maintaining anonymity while ensuring accountability. We are an ambitious, self-funded start-up with founders who have backgrounds in AI, Hedge Funds, Biotech, and Energy Production. Headquartered in London, our technical team is distributed across the UK and France. Working independently allows us to move quickly, innovate freely, and stay focused on creating cutting-edge cryptographic, blockchain, and mobile-first privacy tools.
About the Role
We’re seeking a Senior React Native Engineer to help build, refine, and scale our encrypted email application, C.Email. You’ll collaborate closely with our CTO, cryptography expert, and engineering team to deliver a secure, intuitive, and high-performing product. This is a hands‑on role with full ownership of features — from development and testing through to deployment and user experience improvements. Your work will directly influence how millions of people communicate securely.
Responsibilities
- Lead development of key features from concept through release, taking full responsibility from early design discussions to testing and deployment.
- Build and improve the C.Email mobile application using React Native (Expo + CNG).
- Enhance app performance and stability; address bugs and UI issues.
- Integrate and optimise cryptographic components for performance.
- Produce modular, testable, and maintainable code with clear documentation.
- Create and maintain automated testing frameworks (unit, component, and user simulation).
- Work with blockchain engineers on integrations related to data backup and key management.
- Participate in daily stand‑ups and code reviews, contributing ideas and best practices.
Qualifications
- Extensive experience with React Native and TypeScript.
- Strong background in building automated test suites — unit, component, and user‑simulation.
- Solid understanding of mobile‑first architecture (local storage, offline‑first workflows).
- Experience in startups or small engineering teams (Series A/B or pre‑VC).
- Demonstrated ability to take ownership of product areas or features.
- Exposure to email protocols and standards (MIME, Gmail API) is beneficial.
Required Skills
- React Native (Expo) – advanced development and optimisation.
- Kotlin / Swift – for native modules.
- Go – used in cryptographic components.
- C++ – for performance and integration‑related tasks (secondary).
- GCP / AWS (basic) – setup and management of light infrastructure (SES, Lambda, Redis, RDS, EC2 autoscaling).
- Understanding of cryptographic concepts (key exchange, signing, encryption).
Preferred Skills
- Familiarity with email standards and protocols (e.g., MIME, Gmail API).
What’s Next?
- Talent Acquisition Interview (30–45 minutes) – an introductory call to learn about Certonymity’s mission and your background.
- Practical coding exercise (60–90 minutes) – a live coding session with our CTO and a Senior Engineer based on a task we’ll provide.
- Final Stage Interview (30 minutes) – meet our CEO and founder to discuss the role and company in more depth.
Senior Software Engineer in London employer: Certonymity
Contact Detail:
Certonymity Recruiting Team
StudySmarter Expert Advice 🤫
We think this is how you could land Senior Software Engineer in London
✨Tip Number 1
Network like a pro! Reach out to people in the industry, especially those connected to Certonymity. A friendly chat can open doors and give you insights that a job description just can't.
✨Tip Number 2
Prepare for your coding exercise by brushing up on React Native and TypeScript. We want to see your skills shine, so practice common problems and be ready to showcase your thought process during the live session.
✨Tip Number 3
Don’t underestimate the power of a good follow-up! After your interviews, drop a quick thank-you note to express your appreciation and reiterate your excitement about the role. It keeps you fresh in their minds!
✨Tip Number 4
Apply through our website! It’s the best way to ensure your application gets seen by the right people. Plus, it shows you’re genuinely interested in being part of our mission at Certonymity.
We think you need these skills to ace Senior Software Engineer in London
Some tips for your application 🫡
Tailor Your CV: Make sure your CV reflects the skills and experiences that align with the Senior Software Engineer role. Highlight your experience with React Native, TypeScript, and any relevant projects that showcase your ability to take ownership of features.
Craft a Compelling Cover Letter: Use your cover letter to tell us why you're passionate about secure communication technology. Share specific examples of how you've contributed to similar projects in the past and how you can help us innovate at Certonymity.
Showcase Your Technical Skills: In your application, don’t forget to mention your experience with automated testing frameworks and any exposure to cryptographic concepts. We want to see how your technical background fits into our mission of creating cutting-edge privacy tools.
Apply Through Our Website: We encourage you to apply directly through our website. This way, we can ensure your application gets the attention it deserves, and you’ll be one step closer to joining our ambitious team!
How to prepare for a job interview at Certonymity
✨Know Your Tech Inside Out
Make sure you’re well-versed in React Native and TypeScript, as these are crucial for the role. Brush up on your knowledge of mobile-first architecture and cryptographic concepts, as you’ll need to demonstrate your expertise during the technical discussions.
✨Showcase Your Problem-Solving Skills
Be prepared to tackle a practical coding exercise during the interview. Practice common coding challenges and think aloud while solving them. This will not only show your thought process but also how you approach problem-solving in real-time.
✨Understand the Company’s Mission
Familiarise yourself with Certonymity’s mission to simplify encrypted communication. Be ready to discuss how your skills can contribute to their goals, especially in enhancing user experience and security in the C.Email application.
✨Engage with the Team
During the interviews, don’t hesitate to ask questions about the team dynamics and the company culture. Showing genuine interest in collaboration and innovation will resonate well with the founders, who value independent yet cohesive teamwork.
