Case StudyFintechDigital Banking

Neo-Bank Payment Rails

Scaling a Singapore neo-bank's payment rails to handle 10x transaction growth.

ProjectOverview

A MAS-licensed digital bank was outgrowing its payments core. Zimozi re-engineered its payment-rail integrations and performance-testing strategy so it could clear PayNow, FAST and GIRO volume at scale, without downtime, ahead of a major customer-acquisition push.

Industry: Digital Bank / Neo-bank · Region: Singapore (MAS-regulated) · Services: Payment Rails Integration, Performance Engineering · Engagement: 7 months. Client identity withheld under NDA; figures representative of the engagement outcome.

TheChallenge

The bank had launched fast and won customers quickly, but its payment integrations were tightly coupled to a single processor with ad-hoc retries. Leadership was about to switch on a large acquisition campaign and needed certainty that real-time payments would not buckle.

Unknown breaking point

No production-grade load model, so the team could not say how many TPS before degrading.

Brittle rail integrations

PayNow / FAST / GIRO flows were coupled and synchronous, so slow responses cascaded into timeouts.

Resilience & compliance gaps

Limited failover and observability made it hard to evidence MAS TRM resilience expectations.

Release risk

No automated performance gate meant regressions could reach production unseen.

The Solution

We modelled the real world, then engineered for it.

We reconstructed true traffic shapes, payday surges, promo spikes and end-of-month GIRO batches, into a repeatable performance-test suite running against a production-like environment.

We introduced an asynchronous payment-orchestration layer with idempotency keys, queue-backed retries and circuit breakers, so a slow rail degrades gracefully instead of cascading, hardened with active-active deployment across availability zones and ISO 20022 message handling.

Load tests were wired into CI/CD so every payments change is benchmarked automatically, regressions fail the build, not the customer.

KeyFeatures

An orchestrated, observable payments backbone that absorbs spikes instead of failing.

01

Realistic
load modelling

Reconstructed true traffic shapes into a repeatable performance-test suite.

02

Decoupled
payment rails

Async orchestration with idempotency keys, queued retries and circuit breakers.

03

Active-active
resilience

Multi-AZ deployment and ISO 20022 message handling for clean interoperability.

04

Live observability

A real-time dashboard for throughput, latency and success rate across every rail.

05

Performance
as a release gate

Every payments change is load-tested automatically in CI/CD.

TechStack

PayNow, FAST and GIRO integrations on event-driven microservices, Kafka queues and Kubernetes, hardened with active-active multi-AZ deployment and k6 load testing in CI/CD.

Kubernetes
Kafka
AWS

Business Impact

Confidence to scale, and the evidence to prove it.

The platform sustained 12,000+ transactions/sec at peak load with p99 latency under 350ms and 99.99% availability post-launch, giving the bank 10x throughput headroom and ~70% fewer payment errors.

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