640 Javascript jobs in London

Node.js / TypeScript Developer (Backend-Focused)

£60,000 - £90,000 | Hybrid (4 days remote) | London

We’re supporting a purpose-driven tech company operating at the intersection of data, software, and healthcare, a business using technology to drive better health outcomes on a global scale.

They’re now looking for a Node Developer (Backend) who’s excited by the opportunity to build scalable, high-performing systems that make a tangible difference.

You’ll play a key role in shaping the technology that powers their modular platform — working closely with cross-functional teams to deliver new features, improve existing systems, and accelerate the product roadmap. This is a team that values ownership, creativity, and pragmatic problem-solving (sometimes the best solution isn’t starting from scratch).

The Opportunity:

In this role, you’ll be building and optimising backend systems and APIs that underpin the platform, working closely with cross-functional teams to deliver secure, scalable, and high-quality software.

You’ll have the freedom to take ownership of your projects, challenge how things are done, and use modern AI-driven tools to accelerate delivery and boost performance.

It’s a great fit for someone who enjoys autonomy, thrives in collaborative teams, and understands that building smarter doesn’t always mean building from scratch.

What You’ll Bring:

• Solid commercial experience with Node.js and TypeScript
• Strong understanding of API development (REST)
• Background working with SQL and NoSQL databases
• At least 3 years’ experience in backend software engineering
• Previous experience within healthcare (FHIR, HL7, EHRs, or LIMS) or exposure to Software as a Medical Device (SaMD) is highly desirable
• A proactive mindset and ability to adapt within a fast-moving environment

At MRJ, we make efforts to truly do things differently. In partnering closely with this client, you’ll get the inside track on the opportunity, the team culture, and what it takes to land the role. We’ll be with you every step of the way.

Drop us a message and we'll be in touch

Job Title: JavaScript Developer (Contract)

Location: London, UK (Hybrid/On-site depending on client)

Contract Duration: 6–12 months (with possibility of extension)

Rate: Competitive, depending on experience

About the Role:

We are seeking a talented and experienced JavaScript Developer for a contract position based in London. You will work on cutting-edge web applications, collaborating with cross-functional teams to deliver high-quality, scalable, and maintainable solutions. This is an exciting opportunity to contribute to innovative projects in a fast-paced environment.

Key Responsibilities:

• Develop, test, and maintain web applications using JavaScript and related frameworks.
• Collaborate with UX/UI designers, backend developers, and product owners to implement new features.
• Write clean, modular, and well-documented code.
• Troubleshoot and resolve performance, scalability, and usability issues.
• Participate in code reviews, knowledge sharing, and continuous improvement initiatives.
• Stay up-to-date with the latest industry trends and technologies.

Required Skills and Experience:

• Strong proficiency in JavaScript (ES6+) .
• Hands-on experience with front-end frameworks such as React, Angular, or Vue.js .
• Solid understanding of HTML5, CSS3, and responsive design principles .
• Experience with RESTful APIs , JSON, and asynchronous programming.
• Familiarity with version control systems (Git) .
• Ability to write unit and integration tests (e.g., Jest, Mocha, Cypress).
• Strong problem-solving skills and attention to detail.
• Excellent communication skills and ability to work independently or as part of a team.

Desirable Skills:

• Experience with TypeScript .
• Knowledge of Node.js and server-side JavaScript.
• Familiarity with CI/CD pipelines and cloud platforms (AWS, Azure, or GCP).
• Experience working in Agile/Scrum environments.

Why Join Us:

• Work on challenging projects with a supportive team.
• Opportunity to gain exposure to the latest web technologies.
• Flexible working arrangements (hybrid options available).
• Competitive contractor rates.

About Eventogy:

NO AGENCIES - Please do not attempt to canvas from here

Eventogy is a leading event management platform that caters to large corporate enterprise businesses, such as banks, law firms, and government bodies. We specialise in providing event management solutions for highly regulated industries, with a strong focus on security and compliance. As a design-first organisation, we are currently undertaking a complete rebuild of our platform to create an even more intuitive and engaging user experience.

We are seeking a skilled Javascript Developer to join our team and play a crucial role in implementing our redesigned platform. The successful candidate will work closely with our design and development teams to create pixel perfect and highly functional web applications, ensuring an exceptional user experience.

Responsibilities:

1. Collaborate with UX/UI designers and back-end developers to create visually appealing, user-friendly, and highly functional and responsive web applications.
2. Convert designs and wireframes into high-quality HTML, CSS, and JavaScript code.
3. Optimize applications for maximum speed, scalability, and responsiveness.
4. Ensure consistent implementation of brand and design guidelines across all platforms.
5. Develop and maintain reusable code and libraries for future use.
6. Stay up-to-date with the latest front end development technologies and best practices.
7. Conduct thorough testing and debugging to ensure the seamless functioning of applications.
8. Collaborate with cross-functional teams, including product managers, developers, and stakeholders, to define and implement innovative solutions for the product direction, visuals, and user experience.

Requirements

1. A Bachelor's degree in Computer Science, Web Development, or a related field.
2. A minimum of 3 years of experience as a Front End Developer, preferably in the event management or technology sector.
3. Proficient understanding of web markup, including HTML5, CSS3, and JavaScript.
4. Experience building NextJS Web Applications using Typescript.
5. Familiarity with TailwindCSS.
6. Experience with responsive and adaptive design, as well as an understanding of the technical limitations and constraints of web applications.
7. Strong understanding of cross-browser compatibility issues and ways to work around them.
8. Knowledge of code versioning tools, such as Git.
9. Excellent problem-solving skills and a keen eye for detail.
10. Strong communication and teamwork skills, with the ability to work effectively with cross-functional teams.

Benefits

All applicants MUST have working Visas or be UK residents and be currently present in the UK.

This is a hybrid role and we can negotiate the terms of your office presence, but for your information, we currently come in 2-3 times a week to the Farringdon office in London.

We have the finest coffee shop on our doorstep. A food market right in front of the office. Access to gym membership, with conditions! Training is catered for as and when needed. Pret coffee subscription included

NO AGENCIES - Please do not attempt to canvas from here.

Salary: from £50,000 subject to qualification.

Principal JavaScript Engineer (TypeScript / React / Node.js)

£150,000–£170,000 + Equity | Hybrid – 3 days in London

We’re helping a VC-backed SaaS scaleup reinvent how organisations manage and approve spend, from software requests to supplier onboarding, and they’re gearing up for serious growth. With enterprise clients already on board and revenue climbing, they’re looking for an outstanding Principal Engineer to drive their platform forward.

The company in a nutshell

• Funding : $25M Series A from top-tier investors
• Leadership : Founders with a track record of building one of Europe’s best-known B2B scale-ups
• Growth : Plans to 10× revenue and expand to 200+ enterprise customers within 3 years

What’s on offer

• Influence the architecture and scalability of a modern, cloud-native, no-code platform
• Build features from scratch and own them through deployment and user impact
• Work with a high-trust engineering culture where product ownership is real, not buzzwords
• Ship fast — multiple times a day — thanks to a rock-solid CI/CD setup
• Collaborate closely with product, design, and leadership to shape the roadmap

Tech stack you’ll be working with : TypeScript, React, Node.js, AWS Serverless (Lambda, DynamoDB, EventBridge)

What you’ll be doing:

This isn’t just about writing code, it’s about owning problems end-to-end and influencing every part of the product lifecycle.

You’ll:

• Lead the design and delivery of high-impact, full-stack features from concept to production.
• Make key architectural decisions to ensure our systems remain fast, reliable, and observable as we scale to hundreds of enterprise customers.
• Collaborate closely with product, design, and leadership to set roadmap priorities and define technical strategy.
• Work across the stack — from React frontends to AWS serverless backends — and own your projects from infrastructure to styling.
• Deploy continuously (multiple times per day) using their robust CI/CD pipelines.
• Mentor other engineers and help grow a high-performance, high-trust team.

What we’re looking for:

• 6–10+ years in software engineering (open to exceptional candidates outside this range)
• Proven full-stack ability with TypeScript, React, and Node.js
• Experience with AWS serverless technologies
• Passion for delivering excellent products at speed without sacrificing quality
• Experience scaling early-stage products or leading top-tier engineering teams

You’ll thrive here if you:

• Love working in high-growth, fast-moving environments
• Naturally take ownership rather than waiting for instructions
• Care deeply about clean code, great UX, and real customer outcomes
• Have a track record of excellence in any discipline

Benefits

• Hybrid working: 3 days a week in our new Victoria HQ (Tues–Thurs)
• Visa sponsorship and relocation packages are available
• Equity with meaningful upside in a high-growth business
• Work closely with the new VP of Engineering (ex-top European scaleup)
• Engineering team doubling this year — your impact will be huge

Fast hiring process — 2–3 weeks

1. Intro chat with Hiring Manager
2. Pair programming in TypeScript
3. Engineering Culture & System Design
4. Final culture interview

This is your chance to join one of Europe’s most exciting early-stage tech teams — building category-defining software with autonomy, impact, and the kind of growth potential that doesn’t come around often.

Apply now or reach out to Sam Barcia for a confidential conversation.

We’re building a membership platform for the future of live events that prioritises and rewards loyal fans.

At the heart of every meaningful live event lies the desire to feel connected, valued, and part of a shared community. That’s why we built Planet, an end-to-end membership platform that allows artists, venues, and brands to truly understand their audiences.

But we don’t stop there. Through The Beat, our personalisation engine, we go beyond one-off, transactional moments and establish lasting connections with fans. By harnessing insights and learnings from over two years of research into fan engagement, we’re building a future where:

• Loyal fans feel truly seen and prioritised
• Engagement is as seamless and as simple as possible to action

Our vision is to enable impactful, personalised interactions with every fan, fostering deeper connections and more valuable communities. Together, Planet and The Beat help remove the time and resources traditionally required for fan engagement, making it effortless to take every campaign and live event to the next level.

Requirements

As a Full-Stack Engineer, you’ll play a key role in building the next generation of tools and features that power our platform. You’ll work across the stack using TypeScript, Next.js, Apollo GraphQL, and PostgreSQL, delivering functionality that supports fans, artists, and internal teams.

This is a great opportunity to work in a collaborative, fast-paced environment where your code directly shapes the experience of thousands of users.

• Build and maintain features across the stack using Next.js (React), Node.js, Apollo GraphQL, and PostgreSQL
• Collaborate with product, design, and engineering to scope, implement, and iterate on new functionality
• Write clean, maintainable, and well-tested code
• Optimise backend performance and API reliability
• Help refine technical requirements and contribute to architectural decisions
• Contribute to CI/CD processes and deployment automation
• Support internal operations by monitoring infrastructure, resolving issues, and enhancing internal tools as needed
• Participate in code reviews and knowledge-sharing across the team
  

• Solid experience building full-stack applications using TypeScript, Next.js, and Apollo GraphQL
• Comfortable designing and querying GraphQL APIs, both client and server-side
• Strong backend experience with PostgreSQL and relational data modelling
• Familiarity with AWS services, including ECS, Lambda, RDS, and S3
• Experience in CI/CD environments and agile development workflows
• Strong problem-solving skills and an eye for performance and maintainability
• Excellent communication and collaboration skills

• Experience working in a high-demand, live event or fast-moving environment.
• Knowledge of performance testing and simulating high-traffic scenarios.
• Experience with the latest versions of Next.js including app router and server components.
• Experience working with the OpenAI API or similar LLM services

Benefits

What’s it like working at Planet?

We are a remote-first company, but our London office (near Oxford Circus) is available for regular visits for in-person collaboration.

• Our commercial and product teams work together in person 2-3 days a week, but for this role, you can be fully remote with the option to visit the office as needed.
• Our development team is fully remote but based in the UK, with a virtual stand-up each day.

We’ve put structured processes in place to help career progression, including:

• Fortnightly one-on-ones to support your growth
• Monthly creative sessions to spark new ideas
• Quarterly team get-togethers to align on our journey
• A monthly reflection to celebrate wins and lessons learned

• Competitive salary based on experience, with incentives tied to company success
• Join at an exciting time of international growth with the chance to shape your role as part this
• 25 days holiday + UK public holidays, plus additional paid time off between Christmas and New Year
• Remote-first working model, with the flexibility to work from anywhere in the UK
• Quarterly allowance for attending live gigs

What to expect next from us?

1. Initial Chat: A conversation with our Tech Lead to learn more about you and introduce our product, business, and culture.
2. Technical Discussion: A deeper conversation with the core team to see your ideas in action.