Full-Stack Software Engineer I

Kooth

Get hot jobs first on Telegram

New positions appear faster in our channel

Location: UK
Job Type: full-time
Work Format: 🌍 Remote
Salary: £36.5k - £46.5k per annum
Posted: September 26, 2026

Job Description

Kooth is on a mission to remove the barriers that prevent people from accessing the mental health support they need. As the UK’s longest-established digital mental health provider, we create welcoming, accessible spaces where young people can access personalised, effective support in a safe and anonymous way.

Our early-intervention approach empowers young people aged 10–25 to build resilience, access timely support, and lead fulfilling lives. Today, Kooth’s products are available to over 18 million people across the UK and US, connecting them with qualified counsellors and a range of wellbeing resources when they need support.

Our culture is grounded in our values — Alongside You, Flexible, Compassionate, Committed, and Safe — which guide how we support young people, collaborate as a team, and create solutions that meet communities where they are.

You’ll be joining at an exciting time as we continue to grow our product-led strategy and expand access to digital mental health support through Soluna, our innovative behavioural health service for young people.

About the Role

This is a chance to apply your talents to the youth mental health crisis, and to grow as an engineer while you do it.

As a Full-Stack Software Engineer I, despite being at the start of your engineering career, you'll be a meaningful contributor to your squad from the start: building features across the whole stack, learning alongside more senior colleagues, and making a real difference to Kooth's product and business goals. It's an exciting time to join: our new platform has been rebuilt from the ground up on modern tech, ready to support many more young people worldwide in 2027, with plenty of interesting problems still to solve together.

What you’ll be doing

Designing and building RESTful Node APIs, React frontends and/or React Native mobile apps.
Regularly releasing working software, using trunk-based development, automated test suites, and infrastructure-as-code principles.
Incorporating requirements such as performance, resilience, observability, maintainability, security and accessibility.
Collaborating with other disciplines, building effective working relationships.
With your team, achieving a shared understanding of user needs, Kooth commercial and operational goals.
Deepening knowledge of industry trends and best practices in software engineering, continuous integration, application design & architecture through pair/mob programming and other knowledge sharing approaches.
Shadowing the out-of-hours on-call response rota.

Requirements

Key Skills

Enthusiasm for software engineering, across the whole stack
A strong problem-solving attitude and willingness to contribute to technical decisions
Some knowledge of Javascript or Typescript, and of database technologies such as PostgreSQL and experience in delivering a web or native mobile application
A quality mindset, understanding what it means to ship maintainable, well-tested code.
Focus on pragmatic delivery, able to take ownership appropriately
Understanding of the benefits of agile processes, data-informed development, and reliability
Strong communication skills, builds great colleague relationships across disciplines

Nice to have

Web or mobile application development experience using React or React Native
Experience with rapid application development techniques such as trunk-based development, automated testing at all levels and infrastructure-as-code.
An awareness and curiosity about application design and architecture patterns
Worked in a cloud native environment like GCP or AWS with Kubernetes

Benefits

Generous Annual Leave: Enjoy 28 days of annual leave, in addition to public holidays.
Financial Security: Secure your financial future with our pension contributions.
Health and Well-being: Prioritize your health and well-being with our comprehensive AXA Health Insurance and access to an Employee Assistance Programme (EAP). The EAP offers 24/7 telephone mental health support and access to GP consultations, ensuring your mental and physical health are taken care of.
Life Assurance: Gain peace of mind knowing that you're covered with life assurance, providing up to four times your annual salary to your loved ones in the unfortunate event of your passing.
Flexible Working: Embrace the flexibility of hybrid/remote working, allowing you to create a work-life balance that suits your needs and maximizes your productivity.
Lifestyle Benefits: Participate in the Cycle to Work Scheme, promoting a healthy and eco-friendly lifestyle, and take advantage of our Incapacity Income Protection to safeguard your financial stability in case of unforeseen circumstances.

At Kooth, we are committed to fostering an inclusive and diverse workplace that values and embraces the unique contributions of every individual. We believe in equal opportunities for all, regardless of race, colour, religion, gender, gender identity or expression, or sexual orientation.

Our dedication to creating a fair and unbiased environment is reflected in all aspects of our recruitment, hiring, and employment practices. We strive to provide a work environment that is free from discrimination, where every employee is treated with respect and dignity.

Request for Reasonable Adjustments: We are dedicated to providing reasonable adjustments to applicants and employees with disabilities or individuals who require accommodations to participate in the application process, interviews, or job-related tasks. If you require any reasonable adjustments to ensure your equal participation in our recruitment process, please inform our Human Resources team.

Your openness will allow us to work together to provide appropriate accommodations and ensure a fair and accessible application and employment experience for everyone.

Kooth plc is committed to our responsibilities for safeguarding and promoting the welfare of children, young people and vulnerable adults. We are committed to recruiting candidates who share this commitment to safeguarding, and therefore we apply robust recruitment and selection procedures to ensure that the people selected are right for the job, and that all candidates are appropriately screened prior to appointment. This will include a DBS check.

🎯 Who is this job for?

This role is suitable for a Junior-level full-stack software engineer who is enthusiastic about developing across the stack and is ready to grow with support from senior colleagues.

They should have knowledge of JavaScript or TypeScript, databases such as PostgreSQL, web or mobile application development, and ideally React, React Native, automated testing, trunk-based development, infrastructure as code, and cloud platforms.

The person should be familiar with building RESTful APIs and user interfaces, writing maintainable and well-tested code, collaborating in agile multidisciplinary teams, considering security, accessibility, performance and reliability, and contributing to releases and on-call support.

💬 Potential Interview Questions

How would you design a RESTful Node.js or TypeScript API for creating and retrieving wellbeing content?

I would define clear resource-oriented endpoints, validate inputs, return consistent status codes and error formats, and separate routing, business logic, and data-access concerns. I would also add authentication, authorization, structured logging, automated tests, and API documentation.

How would you structure a React application to keep it maintainable as it grows?

I would organize the application around reusable components and feature-oriented modules, keeping presentation, state management, and API communication appropriately separated. I would use clear TypeScript interfaces, predictable data flow, accessibility-aware components, and focused unit and integration tests.

What is trunk-based development, and how would you use it safely?

Trunk-based development means integrating small, short-lived changes frequently into a shared main branch. Automated tests, code review, feature flags, and a reliable CI pipeline help ensure that incomplete or risky functionality can be merged without destabilizing production.

How would you test a full-stack feature from the frontend through to PostgreSQL?

I would use unit tests for isolated business logic, component tests for React behaviour, API tests for endpoint contracts, and integration or end-to-end tests for critical user journeys. Tests should also cover validation, authorization, failure cases, and database interactions using controlled test data.

What steps would you take to secure an API handling sensitive mental health information?

I would enforce strong authentication and least-privilege authorization, validate and sanitize all input, use encrypted transport and secure secret management, and avoid exposing sensitive data in logs or error messages. I would also apply secure headers, dependency scanning, audit logging, retention controls, and regular security reviews.

How would you improve the performance of a slow React page or mobile screen?

I would measure first using browser or mobile profiling tools, network traces, and user-focused metrics. Depending on the cause, I might reduce unnecessary renders, memoize carefully, paginate or cache data, optimize assets, defer non-critical work, and improve API response times.

How would you design an application to be resilient when a dependent service is unavailable?

I would use timeouts, bounded retries with backoff, graceful fallbacks, idempotent operations, and appropriate circuit-breaking where necessary. Health checks, clear user-facing behaviour, monitoring, and alerts would help the team detect and respond to failures without causing cascading outages.

What observability would you add to a Node.js service running in the cloud?

I would provide structured logs with correlation identifiers, metrics for latency, throughput, errors, and resource usage, and distributed traces across service boundaries. Dashboards and actionable alerts should focus on user impact and meaningful service-level objectives rather than generating excessive noise.

How would infrastructure-as-code and Kubernetes support this application?

Infrastructure-as-code allows environments, permissions, networking, and supporting services to be versioned, reviewed, and reproduced consistently. Kubernetes can manage container scheduling, scaling, service discovery, and rolling deployments, while readiness probes, resource limits, and secure configuration improve reliability.

What accessibility considerations are important when building a React or React Native product for young people?

I would use semantic elements or accessible native components, full keyboard or assistive-technology support, meaningful labels, sufficient colour contrast, scalable text, and clear focus and error states. Accessibility should be tested throughout development with automated tools and manual testing, not treated as a final-stage task.

📋 Job Summary

Kooth is the UK’s longest-established digital mental health provider, creating safe, accessible products that connect young people with personalised support. As a Full-Stack Software Engineer I, you’ll build and release RESTful Node.js APIs, React frontends, and React Native apps while contributing to testing, accessibility, security, observability, and infrastructure-as-code. This is a full-time, UK-remote role using JavaScript/TypeScript, PostgreSQL, React, React Native, and cloud-native technologies such as AWS or GCP and Kubernetes. With a salary of £36,500–£46,500, strong benefits, and meaningful opportunities to grow, it’s an excellent chance to develop your engineering career while improving young people’s mental health.