6,760 Back End Developers jobs in the United Kingdom

Meet DeepL
DeepL is a global communications platform powered by Language AI. Since 2017, we've been on a mission to break down language barriers. Our human-sounding translations and intelligent writing suggestions are designed with enterprise security in mind. Today, they enable over 100,000 businesses to transform communications, reach new markets, and improve productivity. And, empower millions of individuals worldwide to make sense of the world and express their ideas.

Our goal is to become the global leader in Language AI, building products that drive better communication, foster connections, and make a real-life impact. To achieve this, we need talented individuals like you to join our exciting journey. If you're ready to work with a dynamic team and build your career in the fast-moving AI space, DeepL is your next destination.

What Sets Us Apart
What sets us apart is our blend of modern technology, competitive benefits, and an open, welcoming work culture that enables our people to thrive. When we share what it's like to work at DeepL, the reactions are overwhelmingly positive. This may be because of our products that have helped countless people worldwide or our shared mission to improve communication for individuals and businesses, bringing cultures closer together. What we know for sure is this: being part of DeepL means joining a team dedicated to innovation and employee well-being. Discover what our teams have to say about life at DeepL on LinkedIn, Instagram and our Blog.

Meet the team behind this journey
DeepL has millions of passionate users around the globe, including a growing number of Enterprise teams that depend on workflows that allow for consistent and compliant communication. Our
Customization
team's mission is to deliver the features these teams need, ensuring smoother, faster processes and reducing the need for multiple external tools. By offering intuitive customization features that both enable formatting and styling communication, and enforcing guidelines for compliance, we drive habit-formation and retention, making DeepL the go-to platform for all content refinement tasks.

In this role, you will partner with product managers, designers, researchers and fellow engineers to design and maintain the backend services powering our customization features. As a Senior Backend Engineer, your expertise in building scalable systems using modern technologies (such as C# and .NET Core) will be instrumental in enabling these features horizontally across our products - Translate, Voice and APs. Your contributions will help shape the technical architecture underpinning customization workflows, ensuring enterprise users can efficiently deliver high-quality content. By continuously improving these core services, you'll play a key part in establishing DeepL as an essential component of team-based content creation worldwide.

Your Responsibilities

• Design, implement and maintain features in our microservices in a hybrid cloud environment.
• Contribute to the implementation of end-to-end solutions: design, build and deliver in collaboration with multiple engineering teams.
• Increase the maintainability, reliability, and robustness of our software.
• Continuously improve and automate our development processes.
• Contribute to our backend developer community and share knowledge within and across teams.
• Take total ownership of the work you deliver, from testing and QA to post-deployment monitoring and incident resolution.
• Participate in our on-call rotation: You'll ensure the reliability and availability of our services by being available to join the team's shared on-call rotation as needed.

Qualities we look for

• Proficiency in a modern programming language with solid experience in backend development. Exposure to or familiarity with our tech stack (C#, .NET Core, gRPC) or similar technologies would be beneficial but is not a strict requirement. What's more important is your willingness and ability to learn new technologies quickly.
• Experience in building and maintaining business-critical applications.
• Solid understanding of algorithmic complexity and common data structures.
• Effective and pragmatic: you can weigh between "perfect" and "good enough" depending on priorities and business impact.
• The ability to explain complex ideas and designs to developers and stakeholders with a wide variety of experiences and backgrounds.
• Product mindset: you develop solutions with the customer in mind and iteratively improve your solutions based on data and feedback. You understand how to experiment and track usage for learning.
• You are a role model for continuous delivery. You build incrementally in small batches, practice trunk-based development, and pair-program by default to maintain throughput and team cohesion.
• Comfortable with a hybrid working model and able to come into our London office regularly (2x per week average).
• Fluent in English.

What We Offer

• Diverse and internationally distributed team: joining our team means becoming part of a large, global community with people of more than 90 nationalities. We're more than just colleagues; we're a group of professionals with a shared mission to connect diverse cultures. Our global presence is growing–we've doubled in size nearly every year, with our employees based in the UK, Germany, the Netherlands, Poland, the US, and Japan, and we continue to expand our network
• Open communication, regular feedback: as a language-focused company, we value the importance of clear, honest communication. We value smooth collaboration, direct and actionable feedback, and believe that leading with empathy and growth mindset makes us better together
• Hybrid work, flexible hours: we offer a hybrid work schedule, with team members coming into the office twice a week. This allows you to engage directly with your team and experience the unique energy of our workspace, while still enjoying the flexibility and comfort of working from home. With flexible working hours and trust in your productivity, we are in sync with your team's general locations and time zones to foster effective and seamless collaboration
• Monthly full-day hacking sessions: every month, we have Hack Fridays, where you can spend your time diving into a project you're passionate about and get the opportunity to work with other teams–we value your initiatives, impact, and creativity
• 30 days of annual leave: we value your peace of mind. With 30 days off (excluding public holidays) and access to mental health resources, we make sure you're as strong mentally as you are professionally
• Competitive benefits: just as our team spans the globe, so does our benefits package. We've crafted it to reflect the diversity of our team and tailored it to align with your unique location, to ensure you feel supported every step of the way

If this role and our mission resonate with you, but you're hesitant because you don't check all the boxes, don't let that hold you back. At DeepL, it's all about the value you bring and the growth we can foster together. Go ahead, apply—let's discover your potential together. We can't wait to meet you

We are an equal opportunity employer
You are welcome at DeepL for who you are—we appreciate authenticity here. Our product is for everyone, and so is our workplace. The more voices we have represented and amplified in our business, the more we will all succeed, contribute, and think forward So bring us your personal experience, your perspectives, and your background. It's in our diversity that we will find the power to break down language barriers in the world.

About Medly AI

We're the fastest growing EdTech startup in London, on a mission to change education forever.

We're living through a once-in-a-generation moment where AI-native companies are redefining entire industries - Cursor for code, Midjourney for image gen, Harvey for law. Medly is building a generational company for education.

In just 4 months since launch, we’ve achieved retention rates that beat Duolingo and delivered personalized education to over 100,000 users. We’re looking for ambitious talent to join our team.

Backed by impact-focused VCs and supported by partners including UCL, Innovate UK, Microsoft, and Google, we're becoming the go-to AI education platform for all major exams worldwide.

The Role

We are looking for a passionate Back-End Engineer to join our growing team at Medly. This is a new role working closely with our hands-on Technical CEO other Full Stack Engineers to shape the backbone of our data infrastructure. You will play a pivotal role in high-impact projects such as migrating our systems to AWS, consolidating our databases, worked on our python based AI backend and building a unified environment optimized for cost, latency, and scalability. This is a high-impact opportunity for someone eager to take ownership, solve complex challenges, and help power the next generation of educational technology.

Role Responsibilities

• Build and optimize a unified, cost-efficient, low-latency data environment within AWS
• Work on our AI backend and help make it scale proof
• Help with migration to AWS
• Consolidate mobile and web databases into one optimized Postgres environment
• Develop processes for importing and editing data directly in the database
• Collaborate closely with the CEO and other Full Stack Engineers on high-impact projects

Technical Requirements

• 2–3 years of back-end engineering experience, ideally in a startup environment
• Strong knowledge of Python and Flask
• Proficiency with SQL and Postgres
• Experience with AWS services (migration experience is a plus)

Ideal Candidate

• Quality Focus: Obsessive attention to detail and commitment to shipping polished, bug-free experiences
• Collaborative Spirit: Ability to work closely with designers, product managers, and other developers
• Office Presence: Able to commute 4 out of 5 days a week to our office in Kings Cross, with Wednesday being work from home
• Educational Interest: Passion for education and learning, though specific EdTech experience isn't required
• Startup Mindset: Thrives in fast-paced environments with rapid iteration and high impact
• Innovation Drive: Excited by the opportunity to build cutting-edge educational technology

What We Offer

• Competitive salary
• Opportunity to make a real impact on educational outcomes for students worldwide
• Collaborative, diverse team united by a powerful mission
• Fast-paced environment with significant growth and development opportunities
• Regular team events and a culture focused on innovation and impact
• Work on products used by tens of thousands of students daily
• Shape the future of AI-powered education

About Medly AI

We're the fastest growing EdTech startup in London, on a mission to change education forever.

We're living through a once-in-a-generation moment where AI-native companies are redefining entire industries - Cursor for code, Midjourney for image gen, Harvey for law. Medly is building a generational company for education.

In just 4 months since launch, we’ve achieved retention rates that beat Duolingo and delivered personalized education to over 100,000 users. We’re looking for ambitious talent to join our team.

Backed by impact-focused VCs and supported by partners including UCL, Innovate UK, Microsoft, and Google, we're becoming the go-to AI education platform for all major exams worldwide.

The Role

We are looking for a passionate Back-End Engineer to join our growing team at Medly. This is a new role working closely with our hands-on Technical CEO other Full Stack Engineers to shape the backbone of our data infrastructure. You will play a pivotal role in high-impact projects such as migrating our systems to AWS, consolidating our databases, worked on our python based AI backend and building a unified environment optimized for cost, latency, and scalability. This is a high-impact opportunity for someone eager to take ownership, solve complex challenges, and help power the next generation of educational technology.

Role Responsibilities

• Build and optimize a unified, cost-efficient, low-latency data environment within AWS
• Work on our AI backend and help make it scale proof
• Help with migration to AWS
• Consolidate mobile and web databases into one optimized Postgres environment
• Develop processes for importing and editing data directly in the database
• Collaborate closely with the CEO and other Full Stack Engineers on high-impact projects

Technical Requirements

• 2–3 years of back-end engineering experience, ideally in a startup environment
• Strong knowledge of Python and Flask
• Proficiency with SQL and Postgres
• Experience with AWS services (migration experience is a plus)

Ideal Candidate

• Quality Focus: Obsessive attention to detail and commitment to shipping polished, bug-free experiences
• Collaborative Spirit: Ability to work closely with designers, product managers, and other developers
• Office Presence: Able to commute 4 out of 5 days a week to our office in Kings Cross, with Wednesday being work from home
• Educational Interest: Passion for education and learning, though specific EdTech experience isn't required
• Startup Mindset: Thrives in fast-paced environments with rapid iteration and high impact
• Innovation Drive: Excited by the opportunity to build cutting-edge educational technology

What We Offer

• Competitive salary
• Opportunity to make a real impact on educational outcomes for students worldwide
• Collaborative, diverse team united by a powerful mission
• Fast-paced environment with significant growth and development opportunities
• Regular team events and a culture focused on innovation and impact
• Work on products used by tens of thousands of students daily
• Shape the future of AI-powered education

Overview

GSK is a science-led global healthcare company with a special purpose: to help people do more, feel better, live longer. We are on an audacious journey to impact the health of 2.5 billion people over the next decade. Our R&D division is at the forefront of this mission, dedicated to the discovery and development of groundbreaking vaccines and medicines. We are transforming the landscape of medical research by integrating cutting-edge science and technology and harnessing the power of genetics and new data. By fostering a collaborative environment that unites the talents of our people, we are revolutionizing R&D to pre-empt and defeat diseases. Join us in our commitment to uniting science, technology, and talent to get ahead of disease together.

Role/Project Overview

At GSK we see a world in which advanced applications of Machine Learning and AI will allow us to develop novel therapies to existing diseases and to quickly respond to emerging or changing diseases with personalized drugs, driving better outcomes at reduced cost with fewer side effects. It is an ambitious vision that will require the development of products and solutions at the cutting edge of Machine Learning and AI, as well as extensive safety and robustness evaluations. We’re looking for a highly skilled full stack engineer to help us make this vision a reality.

Competitive candidates will have a track record of writing and shipping quality, well-documented and well-tested software in the AI/ML industry. We are looking for candidates with experience in the field of Responsible AI, preferably for generative AI or language applications. In addition to ML engineering and data science skills, ideal candidates will demonstrate a keen interest in ethical and safety aspects of using AI in drug discovery and the clinic.

The Responsible AI team is built on the principles of ownership, accountability, continuous development, and collaboration. This fixed-term position is a unique opportunity to contribute to the development and evaluation of generative AI for drug discovery in a fast-paced environment, with a focus on impact and in collaboration with a large team. Our leaders will be committed to your career and development from day one.

 Key Responsibilities

• Backend development of generative AI evaluations for a Python web application.
• Integration of AI/ML components with frontend, backend, data and compute infrastructure.
• Responsible for high quality software implementations according to best practices, including automated test suites and documentation.
• Participate in code reviews, continuously improving personal standards as well as the wider team and product.
• Liaise with other technical staff and data engineers in the team and across allied teams, to build an end-to-end pipeline consuming other data products.
• Deliver ML- and data-driven insights on GenAI datasets.

Minimum Qualifications

• A degree in a quantitative or engineering discipline (e.g., computer science, computational biology, bioinformatics, engineering, among others); OR equivalent work experience as a professional ML engineer or data scientist.
• Strong skills in Python, with experience in backend development and unit testing.
• Knowledge of generative AI, specifically Large Language Models.
• Knowledge of agile practices and able to perform in agile software development environments.
• Strong knowledge of modern software development tools / ways of working (e.g. git/GitHub, DevOps tools for deployment) – should be able to show practice of commit early and deploy often.

Preferred Qualifications

• Experience with safety and/or robustness evaluations of generative AI, e.g. defining guardrails, red teaming or persona-based evaluations.
• Knowledge of AI/ML approaches and deployment of AI/ML powered applications – especially using language models or NLP and agent-based approaches (e.g. LangGraph, PydanticAI, AutoGen),
• Knowledge of AI/ML evaluation and benchmarking approaches, experience with iterative improvement of AI/ML models and products.
• Research experience (e.g., Master’s project, internship at research organization).
• Cloud experience (e.g. Google Cloud and cloud run preferred) including core web application infrastructure.

Why GSK?

Uniting science, technology and talent to get ahead of disease together.

GSK is a global biopharma company with a special purpose – to unite science, technology and talent to get ahead of disease together – so we can positively impact the health of billions of people and deliver stronger, more sustainable shareholder returns – as an organisation where people can thrive. We prevent and treat disease with vaccines, specialty and general medicines. We focus on the science of the immune system and the use of new platform and data technologies, investing in four core therapeutic areas (infectious diseases, HIV, respiratory/ immunology and oncology).

Our success absolutely depends on our people. While getting ahead of disease together is about our ambition for patients and shareholders, it’s also about making GSK a place where people can thrive. We want GSK to be a place where people feel inspired, encouraged and challenged to be the best they can be. A place where they can be themselves – feeling welcome, valued, and included. Where they can keep growing and look after their wellbeing. So, if you share our ambition, join us at this exciting moment in our journey to get Ahead Together.

Inclusion at GSK

GSK is an Equal Opportunity/Affirmative  Action Employer. All qualified applicants will receive equal consideration for employment without regard to race, color, national origin, religion, sex, pregnancy, marital status, sexual orientation, gender identity/expression, age, disability, genetic information, military service, covered/protected veteran status or any other federal, state or local protected class.

If you need any adjustments in the recruitment process, please get in touch with our Recruitment team ( ) to further discuss this today.

Important notice to employment businesses/agencies

GSK does not accept referrals from employment businesses and/or employment agencies in respect of the vacancies posted on this site. All employment businesses/agencies are required to contact GSK's commercial and general procurement/human resources department to obtain prior written authorization before referring any candidates to GSK. The obtaining of prior written authorization is a condition precedent to any agreement (verbal or written) between the employment business/ agency and GSK. In the absence of such written authorization being obtained any actions undertaken by the employment business/agency shall be deemed to have been performed without the consent or contractual agreement of GSK. GSK shall therefore not be liable for any fees arising from such actions or any fees arising from any referrals by employment businesses/agencies in respect of the vacancies posted on this site.

Please note that if you are aUS Licensed Healthcare Professional or Healthcare Professional as defined by the laws of the state issuing your license, GSK may be required to capture and report expenses GSK incurs, on your behalf, in the event you are afforded an interview for employment. This capture of applicable transfers of value is necessary to ensure GSK’s compliance to all federal and state US Transparency requirements. For more information, please visit GSK’s Transparency Reporting For the Record site.

About Seapoint
Seapoint is building the financial home for European startups and scale-ups. We're an AI-powered business account that handles everything from payroll and expenses to invoice payments and reporting - all in one place.

Founded by Sean Mullaney (former European CIO at Stripe) and a team of alumni from Stripe, Wise, Wayflyer, Nubank and Tide, we've just raised $3M in pre-seed funding led by Frontline Ventures. After 9 months of building, we're now in private beta with dozens of VC-backed startups who are finally getting the bird's-eye view of their finances they've always needed.

The problem we're solving is real: European startups are stuck between neobanks (too small) and traditional corporate banking (too big). They're juggling 4-6 different financial products, running processes manually, and earning no interest on cash deposits. We're changing that with AI automation that handles the tedious financial work, so founders can focus on building their businesses instead of managing spreadsheets.

Read more about what we’re building here .

About the role
Build the financial infrastructure that powers the next generation of startups.

You'll architect core systems for multi-currency accounts, automated payments, and treasury management—technology that high-growth companies depend on to scale. Working with modern distributed systems, you'll tackle complex financial challenges while ensuring the reliability and security our users trust.

We're looking for engineers with varying backgrounds who are passionate about building something new. You'll work alongside ex-founders and veterans from Stripe, Wise, and Tide who understand what startups need to scale.

Languages and frameworks can be learnt, but if you’re curious we use a modern typescript and bun backed stack with postgreSQL and a bunch of AWS services. We are always curious about new ways of building software and embrace AI tools.

Note: Open to candidates authorised to work in Ireland/UK. Exceptional remote candidates across Europe considered.

Requirements

What matters: Systems thinking, attention to detail, and a drive to solve real problems for founders.

Essential Qualifications:

• Strong software engineering skill and a passion for startup life and helping founders
• 5+ years of professional software development experience
• Fluency in Typescript or a major programming language like Java, Ruby, Go, Python, etc

• Strong product instincts—showcase prior experience in designing and developing key customer features at scale
• Interest in leveraging AI for genuine financial solutions
• Fintech domain experience will be highly valued but not required

Benefits

• Competitive salary with meaningful equity in a fast-growing fintech startup
• Work directly with experienced founders and engineers from Stripe, Tide, Wise, Nubank, Wayflyer and other fintech unicorns
• Front-row seat to building category-defining financial infrastructure for Europe's startup ecosystem
• Flexible hybrid working from our Dublin base
• Learning and development opportunities in fintech and AI

• Designing, developing, and maintaining robust and scalable backend services and APIs.
• Implementing data storage solutions and optimising database performance.
• Collaborating with frontend developers to integrate user-facing elements with server-side logic.
• Writing clean, efficient, well-documented, and maintainable code.
• Developing and implementing unit, integration, and end-to-end tests.
• Participating in code reviews to ensure code quality and share knowledge.
• Troubleshooting, debugging, and resolving production issues.
• Working with cloud platforms (e.g., AWS, Azure, GCP) to deploy and manage applications.
• Staying up-to-date with emerging backend technologies and best practices.
• Contributing to architectural discussions and technical decision-making.

• Design, develop, and maintain scalable backend services and APIs.
• Write clean, efficient, well-documented, and testable code.
• Develop and manage database schemas and optimize query performance.
• Implement robust security and data protection measures.
• Collaborate with cross-functional teams to define, design, and ship new features.
• Participate in code reviews to ensure code quality and share knowledge.
• Troubleshoot, debug, and upgrade existing systems.
• Contribute to architectural decisions and technical roadmaps.
• Implement and manage CI/CD pipelines for automated testing and deployment.
• Mentor junior engineers and contribute to team knowledge sharing.
• Stay current with emerging backend technologies and industry best practices.
• Ensure the performance, quality, and responsiveness of applications.

• Bachelor's or Master's degree in Computer Science, Engineering, or a related field, or equivalent practical experience.
• 5+ years of professional experience in backend software development.
• Proficiency in one or more backend programming languages (e.g., Python, Java, Node.js, Go, C#).
• Strong experience with relational databases (e.g., PostgreSQL, MySQL) and/or NoSQL databases (e.g., MongoDB, Cassandra).
• Expertise in designing and building RESTful APIs.
• Familiarity with cloud platforms (AWS, Azure, GCP) and microservices architecture.
• Experience with containerization technologies (Docker, Kubernetes) is a plus.
• Solid understanding of software development principles, design patterns, and data structures.
• Experience with testing frameworks and methodologies.
• Excellent problem-solving, analytical, and debugging skills.
• Strong communication and collaboration skills, particularly in a remote environment.

Salary banding: £65,000 - £80,000 dependent on experience

Working pattern: Hybrid; 1-2 days per week in the office

Location: London

As a business which has AI at its core, we need to have a reliable, scalable and secure real-time ML platform to deliver our product to customers. The Engineering team makes this happen.

The team is UK-based, with a significant contingent in London, and is made up of pragmatic, curious and collaborative problem-solvers who are passionate about working with our Data Scientists to build state of the art AI products. Our Software Engineers bring together a diverse range of expertise and backgrounds; what unites us is a desire to learn, a mastery of our discipline and strong technical prowess.

Our engineers are responsible for all aspects of the software development lifecycle. You will get the opportunity to work across our entire stack building features which deliver AI capabilities to some of the biggest names in the insurance industry.

We are developing a modern real-time ML platform using technologies like FastAPI, PyTorch, Ray, k8s (helm + flux), Terraform, Postgres, Flink on AWS, React & Typescript. We operate a fully Python stack except for frontend and infrastructure code. We are very big fans of Infrastructure-as-Code and enjoy Agile practices. 

As a team, we're driven by a relentless focus on delivering real value to customers at speed. We embrace modern engineering practices such as automated testing, continuous monitoring, feature flags, and on-demand production-like environments to support frequent, reliable releases.

Our team is tackling several exciting challenges, including:

• Deploying all changes, including complex machine learning models, reliably to customers within 15 minutes
• Building a real-time, configuration-driven platform that seamlessly adapts to diverse customer needs
• Ensuring autoscaling and cost-efficient model serving in production, with robust support for ML monitoring and experimentation
• Centralised reporting/metrics for both the business and our customers
• Powering user experience of internal and external users through agentic workflows

We are looking for an engineer passionate about developer enablement and infrastructure as code, who is eager to expand their expertise by contributing to impactful product features. You'll play a key role in improving the lives of millions of insurance policyholders globally, working with a modern and powerful technology stack that includes:

• Python for application development
• Terraform for AWS infrastructure provisioning
• Kubernetes (with Helm and Flux) for managing services
• GitLab for CI/CD and version control
• AWS as our infrastructure platform
• PostgreSQL for application data and event sourcing architecture
• Apache Flink for real-time service interactions and state management

• Collaborate with Engineers, Product Managers, and the Engagement team to understand problem spaces, contribute to solution design, and support the development of our product.
• Take responsibility for maintaining and improving parts of our backend stack, following engineering best practices.
• Write robust and well-tested code, including unit, integration, and end-to-end automated tests for backend services that power customer-facing features.
• Participate in code reviews, share feedback with peers, and stay informed about emerging backend technologies and patterns.
• Contribute to platform-related work, using infrastructure-as-code tools (AWS, Terraform, Kubernetes) to help keep our systems reliable and scalable.
• Support the growth of the team by sharing knowledge and collaborating closely with engineers and data scientists.
• Help improve engineering workflows and contribute ideas for refining team processes and delivery methods.
• Play a role in feature rollouts by using feature flags, monitoring metrics, and responding to logs and alerts.
• Embody and promote the Engineering and Sprout company values in your day-to-day work.

• Technical proficiency
• Solid proficiency in software architecture using Python and FastAPI.
• Experience working in fully cloud-hosted environments (e.g. AWS).
• Solid RDBMS experience, preferably with PostgreSQL
• Experience building RESTful APIs (e.g. FastAPI) and real-time data processing pipelines
• Bonus points for experience with Kubernetes, Apache Flink, Flux or Infrastructure-as-Code frameworks (e.g. Terraform).
• Experience of maintaining your own code in a production environment.
• A good foundational understanding of modern software development lifecycles, including code quality, pull requests, code reviews, CI/CD, QA, and production releases in an agile, fast-paced environment
• Strong problem-solving skills with the ability to think critically and creatively
• Collaborative by nature, with excellent communication and teamwork abilities
• Self-motivated, with a strong sense of ownership and accountability