At a Glance
- Tasks: Own full-stack features for a sustainability platform, from backend to user interface.
- Company: Join Sweep, a B Corporation dedicated to tackling climate change.
- Benefits: Flexible hybrid or remote work, competitive pay, and long-term collaboration.
- Other info: Dynamic team culture focused on quality and innovation.
- Why this job: Make a real impact on sustainability while working with cutting-edge technology.
- Qualifications: 5+ years in full-stack development, strong Ruby on Rails and React/TypeScript skills.
The predicted salary is between 63000 - 77000 £ per year.
Sweep is looking for a Senior Fullstack Engineer (freelance) to work on our Sustainability Data Intelligence Platform. Climate change is the defining issue of our time. Sweep builds a sustainability data intelligence platform used by major enterprises to track greenhouse gas emissions, meet regulatory requirements, and drive real decarbonization. We're a B Corporation, and we mean it.
As a Senior Fullstack Engineer, you'll own features end-to-end, from data models and backend systems to the interfaces that make sustainability data actionable. You'll work at the heart of our core product, alongside a team that cares deeply about quality and impact.
What you'll be working on:
- Build and own core product features - Design and implement full-stack features from the ground up: database schema, backend logic, GraphQL API, and React/TypeScript UI.
- Take full ownership of significant parts of the system: reliability, performance, and long-term maintainability are yours to drive.
- Participate in every stage of the development lifecycle, from design and implementation to rollout and smooth operation in production.
- Contribute to and challenge our technical architecture as we scale.
Bring genuine backend depth:
- Design robust data models and schemas built to perform at scale.
- Build and operate backend services, including background jobs, async pipelines, and integrations with third-party systems.
- Own observability: instrument systems, define meaningful metrics, and respond to incidents with confidence.
- Identify and address security risks proactively from API design to infrastructure exposure.
- Automate deployments via our CI/CD systems and continuously improve development processes.
Work with AI as a day-to-day accelerator:
- Leverage AI tools actively in your workflow, from code generation and review to debugging and documentation, to move faster without compromising quality.
- Contribute to how we integrate AI-assisted development practices across the engineering team.
- Stay curious about emerging AI capabilities and bring new ideas on how we can use them to ship better, faster.
Be a team force multiplier:
- Lead technical design on significant features and share your experience openly.
- Review pull requests with rigour and care, raising the bar for the whole team.
- Participate actively in team rituals: stand-ups, planning, retros.
- Contribute to our culture of quality: incremental, well-tested, observable changes.
Pursue quality, always:
- Champion clean code, solid test coverage, and strong engineering practices.
- Improve processes and methodologies to reach the highest standards.
- Bring excellence to your own work and help others do the same.
What do I need to bring?
This is who we’re looking for:
- 5+ years of experience shipping product across the full stack, with strong backend foundations.
- Solid experience with Ruby on Rails in a high-scale production environment is a must.
- Fluent in React/TypeScript on the frontend; deep expertise in relational databases, distributed systems, observability, and security on the backend.
- Comfortable owning features end-to-end with autonomy and clear communication.
- You write clean, well-tested code and take genuine ownership of your work.
Practical Details:
- Hybrid or Remote. Offices in Paris, London, Montpellier, and Denver.
- Start date: ASAP.
- Duration: Long-term collaboration, renewable.
- Rate: 520€.
Senior Fullstack Engineer (Freelance) in London employer: Sweep
At Sweep, we pride ourselves on being an excellent employer that champions innovation and sustainability. Our collaborative work culture fosters creativity and growth, offering employees the chance to work on impactful projects while enjoying the flexibility of remote or hybrid arrangements across vibrant locations like Paris and London. With competitive rates and a commitment to long-term partnerships, we empower our team members to thrive in their careers while making a meaningful difference in the world.
StudySmarter Expert Advice🤫
We think this is how you could land Senior Fullstack Engineer (Freelance) in London
✨Make Your Portfolio Shine
As a freelancer in software development, your portfolio is your bread and butter. Showcase not only your completed projects but also your coding skills on platforms like GitHub or GitLab. This visibility can lead to clients reaching out to you directly!
✨Join Developer Communities
Get involved in developer communities like Stack Overflow or Reddit's r/programming. Contributing to discussions, sharing your knowledge, or even helping others can expand your network and lead to freelance opportunities. Plus, it keeps you in the loop about what’s trending in software development.
✨Freelance Platforms Are Your Friend
Sign up for popular freelance platforms such as Upwork or Freelancer. They’re filled with people looking for talent like yours! Don’t forget to personalise your pitch to each potential client, highlighting how your unique skills can solve their specific problems.
✨Utilise Your Network
Don’t hesitate to reach out to your existing contacts - you never know who might need your services or can refer you to someone who does. Personal connections can lead to more reliable gigs than cold applications. And we're here to help too! If you're looking for freelance opportunities, check out opportunities listed on our website.
We think you need these skills to ace Senior Fullstack Engineer (Freelance) in London
Some tips for your application 🫡
Showcase Your GitHub Projects:When applying for a freelance software engineering gig at Sweep, make sure to include your GitHub link in your application. Highlighting your code repositories, contributions to Open Source, and any personal projects can really set you apart and give us insight into your skills and coding style.
Tailor Your CV with Relevant Skills:In software development, the specifics matter! Make sure your CV lists the programming languages and technologies you excel at. Focus on the ones that align with the projects Sweep is working on. Listing your tech stack clearly will help us understand how you fit into our team.
Include a Portfolio of Your Work:A solid portfolio is a must when applying for freelance roles. Include links to any apps, websites, or software you've developed. Highlight any projects that reflect a strong user experience, efficiency, or innovative solutions—this is your chance to shine and show us what you can bring to the table!
Mention Your Availability and Rates:Since this is a freelance role, we want to know when you’re available and what your rates are like! Be upfront about your typical work hours and project timelines. This transparency will help us see if we can sync up for future projects at Sweep.
How to prepare for a job interview at Sweep
✨Showcase Your Code Wizardry
Since you're going for a freelance role in software engineering, have a solid portfolio ready to flaunt your best work. Include projects that highlight your coding skills, frameworks you excel in, and any problem-solving feats you've pulled off. This is your chance to shine, so choose pieces that reflect your unique style and expertise!
✨Prepare for Technical Challenges
Freelance gigs often involve tech assessments or coding challenges, so be ready to tackle some hands-on problems. Brush up on common algorithms, data structures, and any languages/frameworks relevant to the role at Sweep. Being comfortable with platforms like HackerRank or LeetCode can give you an edge and showcase your skills under pressure!
✨Be Clear About Your Rates and Flexibility
As a freelancer, be prepared to discuss your rates upfront. It's crucial to communicate your pricing structure clearly and whether you're open to negotiation. Do your homework on industry standards to ensure you pitch a fair and competitive rate that reflects your skills and experience!
✨Understand Their Tech Stack
Before the interview, get familiar with the tools and technologies used at Sweep. Whether it's a particular framework or a specific coding methodology, being knowledgeable about their tech stack not only shows your interest but also helps you present how you could fit seamlessly into their existing projects. Demonstrating you’ve done your homework can set you apart from other candidates!
