Junior Javascript Developer jobs in London

About us

At Insightful Technology, we build intelligent solutions that help organisations manage risk, protect data and stay compliant in an ever-changing world. Our products power global enterprises, financial institutions and regulated organisations.

If you want to join a team building extraordinary technical solutions in a compelling working environment where ideas move quickly, people support each other, and innovation is part of everyday life, you’ll feel right at home here.

Role overview

We are looking for an experienced developer with a deep understanding of backend technologies and who is comfortable with some front-end technologies to design and build intuitive, responsive and high-performing user experiences for our technology products. You will take ownership of features throughout their lifecycle, from understanding the user and business need through to technical design, implementation, testing and release. Working closely with developers, product colleagues and other stakeholders, you will help translate complex requirements into clear, accessible interfaces.

This role would suit a self-directed problem-solver who combines strong technical judgement with curiosity, pragmatism and a genuine commitment to user experience.

Key responsibilities

• Design, develop and maintain modern web applications using React and TypeScript.
• Own front-end features from initial requirements and technical design through to testing, deployment and ongoing improvement.
• Translate complex workflows and technical concepts into clear, intuitive user experiences.
• Build reusable, maintainable and well-documented components.
• Integrate front-end applications with REST APIs and services built using C# and .NET.
• Work with product, design, engineering and business stakeholders to refine requirements and propose effective solutions.
• Make considered architectural decisions and communicate the associated options and trade-offs.
• Champion accessibility, performance, security, usability and code quality.
• Write and maintain appropriate automated tests.
• Diagnose and resolve complex technical issues across the application stack.
• Review code and provide thoughtful, constructive feedback.
• Mentor less-experienced developers and encourage knowledge-sharing across the team.
• Contribute to the continuous improvement of our development standards, tools and delivery processes.
• Stay informed about relevant front-end technologies and practices, adopting them when they provide meaningful value.

Required Experience and Skills

Candidates should have at least five years of relevant commercial software development experience. For appointment at senior level, we would ideally expect substantial experience demonstrating technical leadership, architectural judgement and end-to-end ownership.

You will need strong experience with:

• C#
• .NET
• Microsoft SQL Server
• React
• TypeScript
• Modern JavaScript, including ES6+
• HTML5
• CSS
• REST API integration
• Responsive application development
• Accessibility and cross-browser compatibility
• Front-end performance optimisation
• Testing, debugging and code review
• Git or an equivalent version-control system

You should also have experience working with, or a good practical understanding of:

• React
• TypeScript
• Modern JavaScript, including ES6+
• HTML5
• CSS
• REST API integration
• Responsive application development
• Accessibility and cross-browser compatibility
• Front-end performance optimisation
• Testing, debugging and code review

Desirable Experience

Experience with any of the following would be beneficial:

• Material UI
• Entity Framework
• Highcharts or another data-visualisation library
• Vite
• Jest or a comparable testing framework
• IIS
• Octopus Deploy
• TeamCity
• CI/CD pipelines
• Enterprise or regulated software environments
• Applications involving complex datasets, dashboards or analytical workflows

What We Are Looking For

You are likely to succeed in this role if you:

• Take ownership and are comfortable making progress when information is incomplete.
• Approach problems with curiosity, resilience and a solution-focused mindset.
• Keep up with modern tools and development patterns while remaining pragmatic about when to adopt them.
• Can explain complex technical subjects clearly to both technical and non-technical audiences.
• Advocate for users, accessibility and engineering quality without ego.
• Collaborate thoughtfully and respond constructively to different perspectives.
• Pay close attention to the details that affect quality while recognising when a pragmatic solution is appropriate.
• Enjoy mentoring colleagues and raising standards across a development team.

What Success Looks Like

In this role, you will:

• Deliver valuable, reliable features from concept to production.
• Improve the consistency, usability and performance of our products.
• Make sound technical decisions that support long-term product development.
• Build strong relationships across engineering, product and the wider business.
• Help colleagues develop through mentoring, reviews, and knowledge sharing.
• Strengthen our front-end architecture, practices and engineering standards.

We are looking for someone who wants to do more than execute assigned tasks: someone who can take ownership, influence technical direction, elevate the team and grow with Insightful Technology.

Qualifications

• 3-7 years’ experience in similar/relevant positions.
• Proven track record of building and maintaining enterprise-level backend services using C#.
• Deep understanding of development best practices, including design principles, debugging and testing.
• Strong SQL and relational database design experience required.

Preferred

• Experience embedding agile principles into day-to-day workflows.
• Working experience in any of the following – e-comms surveillance, e-comms, trade reconstruction, transaction monitoring and case management.
• Working understanding of financial datasets.
• Good understanding of financial regulations.

Job details

• Job Type: Permanent
• Location: London, on-site
• We are only accepting applications from within the United Kingdom.

Pay: £55,000.00-£70,000.00 per year

Benefits:

• Company events
• Company pension
• Free or subsidised travel
• Gym membership
• Sick pay
• Work from home

Ability to commute/relocate:

• London EC3V 3DG: reliably commute or plan to relocate before starting work (required)

Experience:

• C#: 3 years (required)

Work authorisation:

• United Kingdom (required)

Work Location: In person