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Fintech / FX — Interchange

Transforming a legacy system and optimising infrastructure costs

We transformed an inherited legacy system into a modern, efficient and cost-effective platform: transaction times cut by 50%, a faster delivery pipeline, and infrastructure costs down 70% — a platform that supports Interchange’s global business at a third of the original cost.

InfrastructureLegacy systemsCost optimisation
The result50%faster transactions — with 70% lower infrastructure costs
Websiteinterchangefx.comSectorFintech
Engagement
  • Team augmentation
  • Project-based development
Stack
  • Kubernetes
  • Terraform
  • Argo CD
  • NX
The client

Interchange

Interchange is a leader in airport operations across multiple countries, offering essential financial services including foreign exchange transactions, money transfers and stock management. To enhance their operational efficiency and global presence, they sought improvements to a legacy system we inherited from a previous development team.

The challenge

Inheriting inefficient systems

Legacy codebase inheritance

The existing codebase was complex, unstable and poorly documented, making it difficult to onboard and deliver improvements swiftly.

Time pressure

The client required a swift move to production, which demanded rapid issue identification and resolution.

Inefficient CI/CD pipeline

The CI/CD process took over 30 minutes per release, significantly slowing down bug-fixing and testing cycles.

High infrastructure costs

Six Kubernetes clusters for development and testing alone cost around £2,500 per month — excluding production.

What we did
01

Modernising the development pipeline

We identified inefficiencies in the CI/CD pipeline and addressed them by:

  • Refactoring the CI/CD process — replacing custom scripts with industry-standard tools for better maintainability.
  • Introducing NX to handle the monorepo, so only modified parts of the project are rebuilt.
  • Deploying with Argo CD, reducing deployment errors and streamlining the process.
  • Eliminating redundant build steps, cutting release time from 30+ minutes to around 5–6 minutes.

These improvements created a faster feedback loop, letting developers focus on fixes and features instead of deployments.

02

Infrastructure cost optimisation

We rebuilt the entire infrastructure with cost efficiency and scalability in mind:

  • Consolidated six separate Kubernetes clusters into two — one for development and testing, one for production.
  • Separated applications virtually within Kubernetes namespaces instead of running multiple physical clusters.
  • Automated infrastructure with Terraform, making future deployments faster and more reliable.

The changes resulted in a dramatic cost reduction:

  • Monthly infrastructure costs fell from ~£2,500 to £300–400 for development and testing.
  • With production included, total costs were around £700–800 per month — a third of the original.
  • The client saves thousands of pounds annually while keeping robust infrastructure capabilities.
03

Rapid bug resolution and testing

Our initial focus was on stabilising the system:

  • Immediate testing and bug fixes to prepare the system for production.
  • Optimised release cycles enabling quicker iterations and better testing coverage.
Next step

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Interchange — Transforming a legacy system and optimising infrastructure costs · Square21