Backend Software Engineer

About Numeral

Numeral is a payment technology provider that enables fintechs, payment services providers, and banks to launch new products, expand geographically, comply with payment regulations, and scale their operations with Numeral's cloud-native, API-first payments platform.

We develop and run direct integrations with a network of 30+ partner banks (including BNP Paribas, Barclays, Citi, HSBC, Banking Circle, LHV…) that can all be accessed through a single API, webhooks, and dashboard.

Customers include leading and up-and-coming fintechs like Spendesk, Swile, Alma, WorldFirst, Argentex, Deblock, and 20+ others. We have processed more than 4m payments since our first payment in 2023 and will process more than 10m payments over the next 12 months.

Founded in July 2021, Numeral has been acquired by leading core banking system provider Mambu in December 2024. Mambu’s composable core banking system complements Numeral’s API-first payments platform perfectly. Together, we are poised for hyper-growth, serving both Mambu and non-Mambu customers globally, challenging industry giants like FIS, Bottomline, and Volante, and delivering an even greater impact across our ecosystem.

This acquisition marks an exciting new chapter for Numeral. To support this growth, we are hiring across teams to scale our organisation and continue delivering exceptional customer value.

Learn more about Numeral and Mambu:

• Numeral

• Mambu

• Numeral joins forces with Mambu

Our technology stack

Our technology stack is built on a robust microservices architecture, leveraging domain-driven design (DDD) principles and an hexagonal approach to ensure flexibility, scalability, and clear separation of concerns. We prioritize simplicity, maintainability, and adherence to industry best practices, with test-driven development (TDD) at the core of our engineering philosophy.

Our development process is deeply rooted in lean and agile methodologies, fostering a culture of continuous improvement and problem-solving. We embrace an iterative approach, delivering incremental value through frequent releases and short feedback loops.

Backend

• Programming language: Golang

• Messaging: Kafka (AWS MSK)

• Databases: AWS DynamoDB, AWS Aurora PostgreSQL, and AWS RDS

• Caching and In-Memory Data Store: AWS MemoryDB (Redis)

• Search and Analytics Platform: AWS OpenSearch

• Serverless Computing: AWS Lambda

Infrastructure

• Cloud provider: AWS Cloud

• Orchestration: Kubernetes (AWS EKS)

• Infrastructure as code: Terraform

• Monitoring and logging: CloudWatch, Prometheus, Grafana, Datadog…

• CI / CD: GitLab

Frontend

• Programming Language: TypeScript

• Framework: ReactJS

• UI library: Chakra UI

The role

We are hiring Backend Software Engineers across all teams and seniorities. You will join a product and engineering organisation of 20+ people, with 15 more people joining in 2025.

Responsibilities

• Developing bank connectivity and payment automation products, features, and capabilities, with a focus on security, stability, and performance
• Collaborating with Product Managers and DevOps Software Engineers to maintain a fast-paced, iterative, and continuously improved product development and delivery process
• Applying security by design principles to public and internal APIs
• Solving architectural and technical challenges to reduce complexity while creating value for customers and users
• Conducting code reviews and pair programming sessions with peers
• Defining and executing Numeral’s technical roadmap to improve team velocity and control technical debt

Your profile

• Experience with Golang or similar programming languages (general purpose, compiled, statically typed…)
• Experience with relational databases and SQL and familiarity with high concurrent environments, transactions management, and isolation
• Recognize the challenges of running a high-volume SaaS platform at large scale and produce quality, easily maintainable and documented code that respects best practices
• Solid API design skills, with a focus on security and documentation
• You are curious, interested in business understanding and product oriented
• You are autonomous and proactive
• Nice to have: experience in banking and payment systems (SEPA, Swift, Ebics...)
• Nice to have: DevOps appetite - you have been in involved in implementing / using CI using Gitlab and Kubernetes
• Nice to have: cloud hosting with AWS and experience with EC2, S3, EKS, RDS…
• Nice to have: familiar with Kafka or similar message broker middlewares

Compensation and benefits

• Attractive compensation plan including stock options
• Remote-first: work anywhere in Europe and come at your convenience to any Numeral / Mambu office
• International team with 6+ different countries and frequent off-sites
• Sustainable mobility package and lunch vouchers
• Choose the best tools and equipment

Our values

• Make our customers win – What drives us is what we enable for our customers. We go all out to allow them to embed payments powering new products, features, and user experiences. We put our customers first. Our mission is to solve their problems, one at a time. We empower them with the best products. We unlock innovation and business
• No shortcuts – We take great care in what we do so our customers can rely on us. This means taking ownership of problems and solutions, paying attention to details, seeking constant improvement, and never opting for the easy way out
• Embrace feedback – We use humility to stay at the cutting edge. We seek and give honest feedback, we are excited about learning, and we inspire each other to grow
• Think big – We want to have an impact by pushing the limits and tackling complex problems. We don’t give up until we reach success and look forward to our next challenge
• Enjoy the journey together – Entrepreneurship is a journey that is best enjoyed as a team. We enjoy working and spending time together, we inspire each other to achieve great things, and celebrate as a team when they happen

Hiring process

• Screening call with Numeral / Mambu TAM
• Interview #1
• Interview #2
• Technical test
• 2 reference calls