All jobs
What we're looking for
- 3+ years of experience building JavaScript applications in production
- Strong client-side engineering fundamentals with React or a similar framework
- Ability to break down complex problems and design simple, robust solutions
- Good testing habits and attention to quality
- Strong collaboration skills, openness to feedback, and a low-ego working style
About the role
THE CLIENT
Our client is a fast-growing cybersecurity product company rethinking how teams manage and share sensitive access. Their platform is trusted by 40,000+ organisations across 50+ countries — and growing fast. This is an engineering-led business: modern architecture, real technical challenges, and a strong focus on open source, privacy, and security. They’re building a fully remote, collaborative team and looking for engineers who take ownership and enjoy solving meaningful problems. If you want to work on a product with real impact at global scale — this is worth a conversation.
THE ROLE:
Our client is looking for a software engineer to join its Client team and help build the applications through which users experience the product, including browser extensions, desktop applications, command-line tools and SDKs.
This is not a typical frontend role. Because their product is built around end-to-end encryption and a zero-trust model, their client applications carry significant responsibility for security, data handling and product behaviour. The role sits at the intersection of client engineering, product thinking, usability and security-sensitive application design.
You would work on features used by a large open-source community, contributing across the full lifecycle: understanding the problem, shaping the approach, implementing the solution, testing it thoroughly and improving it over time. This role will suit someone who enjoys solving complex product problems, keeping solutions simple, and working in an environment where quality, openness and collaboration matter.
RESPONSIBILITIES:
Build and improve client applications across browser, desktop and adjacent client surfaces
Translate product and user needs into secure, usable client-side solutions
Implement and maintain business logic, local data handling and security-sensitive workflows on the client side
Contribute to testing strategy across unit, integration and end-to-end levels
Work closely with product, design and engineering peers to refine solutions before implementation
Help improve code quality, performance, maintainability and documentation
Contribute to open-source collaboration with the community where relevant
CORE REQUIREMENTS
3+ years of experience building JavaScript applications in production
Strong client-side engineering fundamentals with React or a similar framework
Ability to break down complex problems and design simple, robust solutions
Good testing habits and attention to quality
Comfort working across product, engineering and implementation questions — not just coding tickets
Strong collaboration skills, openness to feedback, and a low-ego working style
Interest in security, privacy, or building trustworthy software systems
NICE TO HAVE
Experience building browser extensions, desktop applications or other multi-platform clients
Experience with security-sensitive applications, client-side cryptography or zero-trust architectures
Experience with design systems, Storybook or usability-focused product development
Open-source contribution experience
Experience maintaining long-lived software products
Familiarity with other languages such as Go, Swift, C#, PHP, Python or Rust
Tools and technologies you’ll work with: JavaScript, React, HTML/CSS, Storybook, Jest, WebdriverIO, OpenPGP-related tooling, Git and Docker across Windows, macOS and Linux environments. (We do not expect candidates to bring experience with every tool listed here)
How you work
You take ownership of problems, not just tasks
You value simplicity and avoid over-engineering
You work well in an environment where feedback is frequent and constructive
Our client is a fast-growing cybersecurity product company rethinking how teams manage and share sensitive access. Their platform is trusted by 40,000+ organisations across 50+ countries — and growing fast. This is an engineering-led business: modern architecture, real technical challenges, and a strong focus on open source, privacy, and security. They’re building a fully remote, collaborative team and looking for engineers who take ownership and enjoy solving meaningful problems. If you want to work on a product with real impact at global scale — this is worth a conversation.
THE ROLE:
Our client is looking for a software engineer to join its Client team and help build the applications through which users experience the product, including browser extensions, desktop applications, command-line tools and SDKs.
This is not a typical frontend role. Because their product is built around end-to-end encryption and a zero-trust model, their client applications carry significant responsibility for security, data handling and product behaviour. The role sits at the intersection of client engineering, product thinking, usability and security-sensitive application design.
You would work on features used by a large open-source community, contributing across the full lifecycle: understanding the problem, shaping the approach, implementing the solution, testing it thoroughly and improving it over time. This role will suit someone who enjoys solving complex product problems, keeping solutions simple, and working in an environment where quality, openness and collaboration matter.
RESPONSIBILITIES:
Build and improve client applications across browser, desktop and adjacent client surfaces
Translate product and user needs into secure, usable client-side solutions
Implement and maintain business logic, local data handling and security-sensitive workflows on the client side
Contribute to testing strategy across unit, integration and end-to-end levels
Work closely with product, design and engineering peers to refine solutions before implementation
Help improve code quality, performance, maintainability and documentation
Contribute to open-source collaboration with the community where relevant
CORE REQUIREMENTS
3+ years of experience building JavaScript applications in production
Strong client-side engineering fundamentals with React or a similar framework
Ability to break down complex problems and design simple, robust solutions
Good testing habits and attention to quality
Comfort working across product, engineering and implementation questions — not just coding tickets
Strong collaboration skills, openness to feedback, and a low-ego working style
Interest in security, privacy, or building trustworthy software systems
NICE TO HAVE
Experience building browser extensions, desktop applications or other multi-platform clients
Experience with security-sensitive applications, client-side cryptography or zero-trust architectures
Experience with design systems, Storybook or usability-focused product development
Open-source contribution experience
Experience maintaining long-lived software products
Familiarity with other languages such as Go, Swift, C#, PHP, Python or Rust
Tools and technologies you’ll work with: JavaScript, React, HTML/CSS, Storybook, Jest, WebdriverIO, OpenPGP-related tooling, Git and Docker across Windows, macOS and Linux environments. (We do not expect candidates to bring experience with every tool listed here)
How you work
You take ownership of problems, not just tasks
You value simplicity and avoid over-engineering
You work well in an environment where feedback is frequent and constructive
Compensation & benefits
Salary: €48k – €65k
About TechTree's client
Optima Search is a One-Stop Talent Shop. As a boutique consultancy, we’re a single touchpoint for hiring across Europe and America for early-stage IPOs and world-class brands. We’re working with quality-driven and hand-picked clients and recruit Tech, Sales, Marketing, Services, Operations, Tech and Executives internationally.