Why Verifone

For more than 40 years Verifone has established a remarkable record of leadership in the electronic payment technology industry. Verifone has one of the leading electronic payment solutions brands and is one of the largest providers of electronic payment systems worldwide.

Verifone has a diverse, dynamic and fast paced work environment in which employees are focused on results and have opportunities to excel. We take pride in the fact that we work with leading retailers, merchants, banks, and third party partners to invent and deliver innovative payments solution around the world. We strive for excellence in our products and services, and are obsessed with customer happiness. Across the globe, Verifone employees are leading the payments industry through experience, innovation, and an ambitious spirit. Whether it’s developing the next platform of secure payment systems or searching for new ways to bring electronic payments to new markets, the team at Verifone is dedicated to the success of our customers, partners and investors. It is this passion for innovation that drives each one of our employees for personal and professional success.

Verifone is proudly an in-office work culture as we see immense benefits to career development and business results from our colleagues being physically co-located.

About The Role

We are seeking a London‑based Senior Software Engineer (Node.js / TypeScript) to build and operate backend services supporting payment, checkout, and transactional workflows. You will collaborate closely with Product, Frontend, Platform, and Infrastructure teams to deliver secure, scalable APIs in high‑throughput environments.

This role sits at the core of Verifone’s payments and checkout platform, where backend engineering directly impacts secure, high‑volume transactions used globally. You’ll design and operate scalable, production‑critical systems that must perform reliably under real‑world load, evolving payment methods, and strict security requirements.

Required Skills and Experience Needed

Programming Languages

• TypeScript (version 3.x or higher)
• Node.js (version 16 or higher)

Backend Frameworks & Libraries

• Backend frameworks such as Hapi.js, or alternatives including Express, Fastify, or NestJS
• Validation using Joi
• Authentication and authorization using JWT and OAuth2

Architecture & Design

• Strong grounding in Clean Architecture and Domain‑Driven Design (DDD)
• Dependency Injection (e.g., InversifyJS)
• Repository and modular design patterns
• Experience building maintainable, testable backend systems

APIs & Data

• Design and operation of RESTful APIs
• API versioning and request validation
• Advanced filtering using RSQL or equivalent
• Experience with MongoDB (modeling, indexing, performance tuning)
• Experience with Redis for caching or messaging
• Database migrations and schema evolution

Cloud & Infrastructure

• Hands‑on experience with AWS services such as EC2, S3, Secrets Manager, and CloudWatch
• Docker and Docker Compose
• Strong discipline with CI/CD pipelines and Git workflows

Testing & Quality

• Automated testing using Jest or Mocha/Chai/Sinon
• End‑to‑end testing with Cypress (optional)
• Strong focus on code quality, reliability, and maintainability

Bonus Skills and Experience

Payments & Security

• Experience integrating payment providers such as Stripe, PayPal, or Klarna
• Knowledge of authorization, capture, and refund flows
• Experience with 3D Secure
• Awareness of PCI‑DSS requirements and security best practices
• Understanding of checkout and transactional domain flows

Production Engineering

• Performance optimization and debugging in production systems
• Exposure to monitoring or APM tools (e.g., AppDynamics or similar)
• Experience operating high‑availability or fault‑tolerant systems
• Familiarity with fraud‑related considerations

Frontend & Platform Exposure

• Experience working alongside frontend frameworks such as Angular or React
• Familiarity with RxJS and state management (NgRx or Redux)
• Server‑side rendering with Pug templates
• HTML/CSS with SASS or PostCSS
• Iframe‑based widget embedding

Additional Bonuses

• Fintech, payments, or e‑commerce domain experience
• Messaging systems such as Kafka, RabbitMQ, or Redis Pub/Sub
• Internationalization (i18n) systems
• Puppeteer for PDF or receipt generation

Our Commitment

Verifone is committed to creating a diverse environment and is proud to be an equal opportunity employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, gender, gender identity or expression, sexual orientation, national origin, genetics, disability, age, or veteran.

We are looking for an engineer with experience in low-level systems programming and optimisation to join our growing ML team. 

Machine learning is a critical pillar of Jane Street's global business. Our ever-evolving trading environment serves as a unique, rapid-feedback platform for ML experimentation, allowing us to incorporate new ideas with relatively little friction.

Your part here is optimising the performance of our models – both training and inference. We care about efficient large-scale training, low-latency inference in real-time systems and high-throughput inference in research. Part of this is improving straightforward CUDA, but the interesting part needs a whole-systems approach, including storage systems, networking and host- and GPU-level considerations. Zooming in, we also want to ensure our platform makes sense even at the lowest level – is all that throughput actually goodput? Does loading that vector from the L2 cache really take that long?

If you’ve never thought about a career in finance, you’re in good company. Many of us were in the same position before working here. If you have a curious mind and a passion for solving interesting problems, we have a feeling you’ll fit right in. 

There’s no fixed set of skills, but here are some of the things we’re looking for:

• An understanding of modern ML techniques and toolsets
• The experience and systems knowledge required to debug a training run’s performance end to end
• Low-level GPU knowledge of PTX, SASS, warps, cooperative groups, Tensor Cores and the memory hierarchy
• Debugging and optimisation experience using tools like CUDA GDB, NSight Systems, NSight Computesight-systems and nsight-compute
• Library knowledge of Triton, CUTLASS, CUB, Thrust, cuDNN and cuBLAS
• Intuition about the latency and throughput characteristics of CUDA graph launch, tensor core arithmetic, warp-level synchronization and asynchronous memory loads
• Background in Infiniband, RoCE, GPUDirect, PXN, rail optimisation and NVLink, and how to use these networking technologies to link up GPU clusters
• An understanding of the collective algorithms supporting distributed GPU training in NCCL or MPI
• An inventive approach and the willingness to ask hard questions about whether we're taking the right approaches and using the right tools
• Fluency in English

If you're a recruiting agency and want to partner with us, please reach out to agency-partnerships@janestreet.com.

Principal Frontend Developer (React)

Location: London (Hybrid) | Practice Area: Technology & Engineering | Type: Permanent

Shape seamless digital experiences that define the future of financial services

The Role

As a Principal Frontend Developer at Capco, you’ll lead the development of scalable and secure web applications for global financial clients using modern JavaScript frameworks, primarily React. You’ll architect responsive, accessible, and elegant user interfaces and work closely with cross-functional teams to deliver transformative digital experiences. As a senior technical leader, you’ll mentor others, influence frontend strategy, and drive best practices.

What You’ll Do

• Architect and implement complex frontend systems using React and modern frameworks

• Apply UX/UI best practices to deliver pixel-perfect, accessible, and responsive applications

• Establish and champion frontend engineering standards across delivery teams

• Coach junior developers, promote knowledge sharing, and contribute to hiring efforts

• Collaborate with stakeholders to translate product needs into technical outcomes

What We’re Looking For

• Strong JavaScript/TypeScript and React expertise; experience with Next.js, Vue.js, or Angular is a plus

• Experience with modern CSS techniques (Flexbox, Grid) and frameworks like SASS, Material UI, Bootstrap

• Familiarity with OAuth2, JWT, OpenID Connect, and secure frontend design principles

• Experience with Redux, Webpack, and modern testing frameworks like Jest, Mocha, or Enzyme

• Track record of delivering applications via CI/CD pipelines and containerised environments (Docker/Kubernetes)

Bonus Points For

• Experience mentoring and coaching frontend developers

• Knowledge of cloud platforms and deployment strategies

• Familiarity with financial services products and regulatory environments

• Experience hiring, managing business cases, and contributing to RFPs

• Strong stakeholder management and communication skills

Why Join Capco

• Deliver high-impact technology solutions for Tier 1 financial institutions

• Work in a collaborative, flat, and entrepreneurial consulting culture

• Access continuous learning, training, and industry certifications

• Be part of a team shaping the future of digital financial services

• Help shape the future of digital transformation across FS & Energy.

Benefits 

We offer a competitive, people-first benefits package designed to support every aspect of your life:

• Core Benefits: Discretionary bonus, competitive pension, health insurance, life insurance and critical illness cover. 

• Mental Health: Easy access to CareFirst, Unmind, Aviva consultations, and in-house first aiders. 

• Family-Friendly: Maternity, adoption, shared parental leave, plus paid leave for sickness, pregnancy loss, fertility treatment, menopause, and bereavement. 

• Family Care: 8 complimentary backup care sessions for emergency childcare or elder care. 

• Holiday Flexibility: 5 weeks of annual leave with the option to buy or sell holiday days based on your needs. 

• Continuous Learning:  Your growth, your way - minimum 40 hours of training annually. Take your pick; workshops, certifications, e-learning. Also, Business Coach assigned from Day One: Get one-on-one guidance to fast-track your goals and accelerate your development. 

• Healthcare Access: Convenient online GP services. 
• Extra Perks: Gympass(Wellhub), travel insurance, Tastecard, season ticket loans, Cycle to Work, and dental insurance.

Inclusion at Capco We’re committed to making our recruitment process accessible and straightforward for everyone. If you need any adjustments at any stage, just let us know – we’ll be happy to help. We value each person’s unique perspective and contribution. At Capco, we believe that being yourself is your greatest strength. Our #BeYourselfAtWork culture encourages individuality and collaboration – a mindset that shapes how we work with clients and each other every day. 

#LI-DNI

Senior Frontend Developer (React)

Location: London (Hybrid) | Practice Area: Technology & Engineering | Type: Permanent

Bring modern web applications to life in the world of financial services

The Role

As a Senior Frontend Developer at Capco, you’ll craft clean, responsive, and secure web applications that enhance digital experiences for global financial clients. Working in an agile environment, you’ll help shape UI solutions using React and modern JavaScript technologies. You’ll play a key role in both hands-on development and guiding best practices across teams.

What You’ll Do

• Build performant and maintainable user interfaces using React (Hooks, Context Suspense) and Typescript
• Develop responsive cross-browser compatible layouts using modern CSS (Flexbox, Grid), CSS-in-JS or modular CSS, and component libraries such as MUI or Tailwind
• Optimise application performance using techniques like code-splitting, memorization, and lazy loading.
• Ensure secure application development following OAuth2, OpenID Connect, and JWT principles
• Collaborate closely with backend, design, and product teams to shape engaging user journeys
• Contribute to team learning through code reviews, mentoring, and sharing best practices

What We’re Looking For

• Strong proficiency in JavaScript (ES5/ES6+) and Typescript
• Hands-on experience building production application in React 18+
• Solid understanding of state management (Context API, Redux Toolkit, or similar)
• Experience consuming RESTful APIs and handling async data with modern patterns
• Strong CSS skills including Flexbox, Grid, and CSS pre-processors like SASS/LESS
• Familiarity with modern build and tooling ecosystems such as Vite, Webpack or similar
• Experience with frontend testing using Jest, React Testing Library, Cypress or Playwright
• A passion for UI performance, quality, and delivering clean code

Bonus Points For

• Exposure to Vue, Angular, or Next.js in production environments
• Understanding of secure application design and frontend performance optimisation
• Experience deploying applications in CI/CD pipelines
• Working knowledge of design systems, component-driven development and tools like Storybook
• Strong debugging skills and ability to work in fast-paced agile teams
• Curiosity for new technologies and experimentation

Why Join Capco

• Deliver high-impact technology solutions for Tier 1 financial institutions
• Work in a collaborative, flat, and entrepreneurial consulting culture
• Access continuous learning, training, and industry certifications
• Be part of a team shaping the future of digital financial services
• Help shape the future of digital transformation across FS & Energy.

Benefits

We offer a competitive, people-first benefits package designed to support every aspect of your life:

• Core Benefits: Discretionary bonus, competitive pension, health insurance, life insurance and critical illness cover.
• Mental Health: Easy access to CareFirst, Unmind, Aviva consultations, and in-house first aiders.
• Family-Friendly: Maternity, adoption, shared parental leave, plus paid leave for sickness, pregnancy loss, fertility treatment, menopause, and bereavement.
• Family Care: 8 complimentary backup care sessions for emergency childcare or elder care.
• Holiday Flexibility: 5 weeks of annual leave with the option to buy or sell holiday days based on your needs.
• Continuous Learning: Your growth, your way - minimum 40 hours of training annually. Take your pick; workshops, certifications, e-learning. Also, Business Coach assigned from Day One: Get one-on-one guidance to fast-track your goals and accelerate your development.
• Healthcare Access: Convenient online GP services.
• Extra Perks: Gympass(Wellhub), travel insurance, Tastecard, season ticket loans, Cycle to Work, and dental insurance.

Inclusion at Capco We’re committed to making our recruitment process accessible and straightforward for everyone. If you need any adjustments at any stage, just let us know – we’ll be happy to help. We value each person’s unique perspective and contribution. At Capco, we believe that being yourself is your greatest strength. Our #BeYourselfAtWork culture encourages individuality and collaboration – a mindset that shapes how we work with clients and each other every day.

#LI-DNI