SITUATION
SOLUTION
TECH STACK
IMPACT
Studies

Equans - AWS estate transformation

Modernising at scale: Equans’ strategic AWS estate transformation

Build as a service

Future-proof AWS foundation

Equans moved away from end-of-life tooling and established a modern, AWS native Infrastructure-as-Code platform with AWS CDK, delivering a scalable, maintainable cloud estate ready for future innovation.

Enhanced security, governance & productivity ‍

Standardised patterns, guardrails, and automated compliance checks, improved governance and security posture, while consistent delivery pipelines reduced manual effort and accelerated developer workflows. CDK Nag ensured that security and compliance checks were built directly into the delivery lifecycle rather than applied retrospectively.

Consistent delivery at scale across nine repositories ‍

Nine disparate repositories were unified with modern CI/CD and refactored code, reducing operational complexity and enabling dependable releases across the entire AWS estate ready to support future growth.

SITUATION

Overview

Equans is a global leader in energy, digital, and industrial services, delivering complex solutions across critical infrastructure and enterprise environments. As a business employing over 90,000 people across 20 countries its HR systems are fundamental to maintaining accurate employee records, as well as ensuring compliance and employee experience.

A key part of its HR function is its starters, leavers and amends process (SLAM), which facilitates approvals and processing for the onboarding of new staff, employee changes and leavers for UK-based employees. Following a period of sustained growth the organisation recognised the opportunity to optimise and enhance their existing platform to maintain performance and achieve cost and operational efficiencies that could support future innovation while maintaining strong governance.

Equans worked with Leighton to modernise their AWS estate behind their SLAM portal, streamline development workflows, and align their platform with AWS best practices. The engagement focused on restructuring legacy Serverless Framework solutions, improving code quality, and introducing modern DevOps pipelines across a large, multi-repository environment.

Solution

The approach

Over time, Equans’ cloud environment had evolved organically. As a result the company recognised the opportunity to improve, enhance and optimise their platform. Multiple services were built using Serverless Framework v2, which was approaching end-of-life. While upgrading to Serverless Framework v3 was an option, it introduced significant licensing costs and additional operational overhead.

With nine repositories requiring migration and refactoring, the scale and complexity of the work demanded a structured, strategic modernisation programme. Leighton worked in close partnership with Equans to design and deliver a comprehensive modernisation initiative that addressed both technical debt and future growth.

Modernisation

Equans needed a new solution that would remove the reliance on outdated tooling and avoid the cost implications with switching to the new Serverless Framework v3. The shift to AWS native tooling would provide long-term maintainability and alignment with best practices. Leighton worked to rebuild all existing solutions using AWS CDK establishing a futureproof Infrastructure as Code foundation using TypeScript.

Consistency, security and governance

Standardised patterns and approaches were introduced across multiple repositories and the engineering team, and embedded best practices, guardrails, and automated compliance checks were used to ensure security and governance. This improved developer productivity through consistent patterns, automated pipelines, and reduced manual intervention. The new solution also enhanced security posture, with automated compliance checks embedded into every deployment.

Scalable delivery pipelines

Legacy application code was refactored to align with modern AWS-native patterns, improving maintainability and readability, DAST, and more advanced Continuous Integration/Continuous Delivery (CI/CD) capabilities. The introduction of more reliable CI/CD, standardised pipelines, automated testing, and governance controls improved developer experience and provided greater confidence in releases.

Tech stack

The modernised SLAM platform was built using a set of AWS-native and open-source technologies that provide a scalable, secure, and maintainable foundation for Equans’ cloud environment. These tools enabled Leighton to replace legacy frameworks, introduce robust Infrastructure as Code, and implement automated delivery pipelines with built-in governance and compliance. Together, this modern tech stack supports consistent, reliable deployments and ensures the platform can evolve efficiently alongside Equans’ future business needs.

AWS CDK

GitHub Actions

TypeScript

CDK Nag

Turborepo

IMPACT

Creating a modern, secure, and scalable AWS foundation to support future growth

By adopting modern AWS tooling and delivery practices, Equans is now positioned to realise significant operational value through a fully compliant, future-ready AWS platform, free from legacy Serverless Framework constraints and the associated licensing costs with upgrading.

The new solution not only reduces operational complexity and offers enhanced security posture but it has also drastically improved developer productivity.

With a modern cloud foundation in place, Equans is well positioned to continue evolving their AWS environment and delivery practices. Ongoing AWS Well-Architected Reviews to reduce technical debt, maintain compliance, and ensure the platform evolves alongside business needs.

Future-proof AWS foundation
Equans moved away from end-of-life tooling and established a modern, AWS native Infrastructure-as-Code platform with AWS CDK, delivering a scalable, maintainable cloud estate ready for future innovation.
Enhanced security, governance & productivity ‍
Standardised patterns, guardrails, and automated compliance checks, improved governance and security posture, while consistent delivery pipelines reduced manual effort and accelerated developer workflows. CDK Nag ensured that security and compliance checks were built directly into the delivery lifecycle rather than applied retrospectively.
Consistent delivery at scale across nine repositories ‍
Nine disparate repositories were unified with modern CI/CD and refactored code, reducing operational complexity and enabling dependable releases across the entire AWS estate ready to support future growth.
Improved code quality ‍
Refactored services aligned with industry best practices, resulting in cleaner, more maintainable, and more performant codebases.
Enhanced developer experience
‍Standardised CI/CD pipelines and monorepo tooling reduced manual effort, accelerated feedback loops, and improved confidence in deployments.

Build as a service

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