Backend engineer for payment systems

At Zepz, our engineers are passionate about delivering a solid customer experience and are eager to contribute to the product, regardless of their tech stack. We are seeking engaged and customer-focused engineers who are committed to writing quality code and dedicated to their contributions at Zepz. As a Senior Backend Engineer on RemittancePlus, you'll work within a cross-functional feature team building and operating Universal Wallet — the multi-currency, crypto-capable wallet powering deposits, withdrawals, and balances for millions of customers across Sendwave.

You will have the autonomy to make platform decisions and provide insights to the rest of the team. You'll collaborate closely with engineers of varying experience levels and interests, helping to improve our services, build pipeline, and tooling across a mixed stack — Python services in sw-backend, and Kotlin/Java services underpinning Universal Wallet. You'll be committing, reviewing, and shipping code early on, with the support and time to ramp up properly, there's a lot to learn across our diverse systems. Reliability is core to the role: the team owns its services in production, and you'll take part in the on-call rotation, responding to incidents, supporting production, and driving remediation and long-term fixes. You will improve code structure and have an impact on architecture. You will actively review tech designs and code from others. You'll improve monitoring and the health of your team's systems. You'll participate in on-call and production support — triaging incidents, restoring service, and following through on remediation so issues don't recur. You build relationships with other engineering teams and identify collaboration opportunities, even without in-person contact. You own larger pieces of work, assist with design and technical/implementation choices, and influence the roadmap within your team. You communicate easily with non-technical team members and can translate their feedback into code.

Requirements:

• 5 years of experience building backend services at scale.
• Strong proficiency in Python and Kotlin/Java (Spring Boot) is expected, as Universal Wallet spans both stacks.
• Experience designing and operating REST/gRPC APIs, event-driven systems, and relational databases (e.g., PostgreSQL).
• Ability to work with AI in a safe, structured environment.
• Ability to work with tools like Grafana and Loki for debugging and fault-finding.
• You take pride in writing readable, well-designed, and well-tested software.
• You write clear, self-contained updates (Slack, Jira, PRs, design docs) that don't require a live conversation to understand.
• You default to documenting decisions and context rather than relying on verbal handoffs.
• You adjust quickly and effectively to shifting priorities and complexity.
• Care about users, and want to give them an improved, simpler experience.
• Are more of a "get it done" than a "perfectionist" type person — you value getting features into the hands of our users.
• Aren't afraid to throw away code you wrote — because after testing, a flow you built doesn't work as well as a different one.
• A genuine curiosity about AI and how it can be applied in your area of work, from accelerating analysis and insight generation, to improving how we design and deliver processes and communications.
• Practical experience using AI tools in a professional context, whether to connect information, draft content, build frameworks, or create insights from data.
• Strong AI literacy.
• An understanding of what AI assistants can and cannot do, how to prompt effectively, and how to critically evaluate AI-generated output before using it.
• Awareness of the ethical considerations and responsible use of AI in the workplace, particularly in the context of sensitive data, customer experience, and compliance.

Desirable:

• Some understanding of Kubernetes, ArgoCD, and AWS cloud is advantageous, as well as technologies like Terraform.
• Experience with Rust, particularly for Solana or other blockchain/crypto integrations — a strong plus given Universal Wallet's stablecoin and on-chain settlement work.
• Experience with wallet, ledger, or payment systems (balances, reconciliation, settlement).
• Familiarity with KYC/AML regulatory requirements in international payments.
• Experience in fintech or other regulated, high-availability environments.
• Familiarity with any of the communities we serve.
• Prior experience using Claude (Anthropic) is a nice-to-have but not essential — what matters most is that you are genuinely engaged with AI as a tool, comfortable experimenting, and eager to share what works with your wider team.

Conditions:

While we have all the tools to work remotely, we value the purpose and benefits of in-person connections so we expect our teams to come to the office on a regular basis, and therefore be within a comfortable commutable distance from our London office. Alongside a great office environment, think unlimited annual leave, great healthcare benefits, and employee discounts.