Senior Backend Software Engineer

We're looking for a Senior Software Engineer in Bengluru to help build and run the core of that platform.

This role covers everything in orchestration - payment flows, routing, connectors, tokenisation, webhooks and reconciliation - and how we run the platform: reliability, on-call, CI/CD and shared engineering practices. We build it, we run it, and done means released, not dev-complete.

WHAT YOU'LL BE DOING

Own core payment flows end to end: authorisation, capture, refund, void and MIT/recurring across card and APM rails, from design doc to production and beyond.

Evolve our routing and recovery logic: rules-based and data-driven routing, decline cascading, Smart Split and outage failover — making sure a retry never becomes a double charge.

Build and maintain connectors to acquirers, APMs and BNPL providers: normalise responses, handle API version drift and design for partner outages.

Design for correctness under failure: idempotency, timeouts, ambiguous payment states, asynchronous notifications and webhooks, and reconciliation against settlement files.

Protect cardholder data: work within our tokenisation and vault services, HSM-backed cryptography and PCI DSS, SOC 2 and ISO 27001 controls, keeping PCI scope as small as possible.

Run the platform: join the on-call rotation, define and track SLOs and service dashboards, write runbooks, lead incidents and blameless RCAs, and improve our GitLab CI/CD and AWS estate (ECS, Lambda, API Gateway, S3).

Raise the bar with the team: write technical design docs, give high-quality code reviews, mentor engineers and help us modernise our stack, including our move to Java 17 and newer Spring Boot.

Work across the business with Product, Solutions, Support and our UK colleagues, turning merchant and partner needs into reliable systems.

ABOUT YOU

Significant experience building and running production backend services in Java and Spring Boot, or a comparable JVM or backend stack and a willingness to move to ours.

A strong grasp of distributed-systems failure modes: retries, idempotency, timeouts, concurrency, eventual consistency, and how to reason about "we don't know if it happened".

Solid PostgreSQL skills (schema design, transactions and isolation, query tuning) and practical use of Redis or similar caches.

Hands-on AWS experience and comfort with CI/CD, containers and infrastructure-as-code.

You've owned services in production: on-call, debugging with logs, metrics and traces, leading incidents and writing up what the team learned.

Clear written communication: design docs, runbooks, RCAs and merge request descriptions that others can act on.

You use AI coding tools productively and critically: you know when to trust the output, and you verify it with tests and review before it ships.

You help the people around you get better through review, pairing and mentoring.

NICE TO HAVE

Payments experience: card acquiring, 3DS2/SCA, network tokens, APMs/BNPL, settlement and reconciliation, or payment orchestration.

Working knowledge of PCI DSS, HSMs and key management, or OAuth2/mTLS for partner integrations.

Observability tooling, SLO-based alerting, or analytics stacks such as Snowflake or QuickSight.

Experience in a Scale-up or Fintech working with UK or global teams.

HOW WE HIRE

Four conversations:

a talent screen,

a conversation with the hiring manager,

a hands-on technical session and

a system design session.

Before your first interview, we'll send you a short guide on how to prepare for each round. You're welcome to use your own AI tools in both technical rounds — we're interested in how you think, verify and decide. Once a decision is made, every candidate receives a written feed-forward from the panel. Tell us about any adjustments you need and we'll make them.

COMPENSATION & BENEFITS

Competitive compensation that recognises your skills, experience and impact.

Generous time off: annual leave, public holidays and wellbeing-focused time away from work.

Work From Anywhere: up to 90 days a year from eligible locations, subject to our policy.

Comprehensive health insurance for you and your loved ones.

Personal accident insurance for when it's needed most.

Enhanced family leave: enhanced parental and family-friendly leave policies.

Learning & growth: opportunities to learn, grow and build a meaningful career at APEXX.

WHO WE ARE & WHERE WE ARE

APEXX is a global payment orchestration platform with teams in the UK and India. For more than a decade we've helped enterprise businesses simplify payments through a single, scalable integration, with access to 200+ acquirers,150+ alternative payment methods and 10+ BNPL providers. We're trusted by leading global brands including Ryanair, TUI, Hotelbeds, CarTrawler, Avon and Jet2.

APEXX is an equal opportunities employer committed to equality, diversity and inclusion.

We do not accept speculative CVs or candidate profiles from recruitment agencies.