If your company wants to remain competitive today, it must modernise its legacy systems. Companies using outdated mainframe applications are limited in the capabilities of their legacy system to grow out of their original function; hence, they suffer from poor scalability, slow rates of innovation and increased maintenance costs.

With the advent of AI-based applications developed by Claude Code, companies can develop their application environment and refactor code more efficiently. We have compiled a list of companies using AI-assisted technologies for their software development. The companies that you will find on our list are well-established engineering-based companies, who have years of experience in the respective industry, and have demonstrated a commitment to providing clients with scalable, future-ready solutions.

Benefits of Using Claude Code for Legacy Modernization

There are many advantages to using Claude Code while modernizing legacy systems. The most notable benefit is accelerated development because of AI-assisted coding which significantly reduces the amount of time needed for code analysis, refactoring and migration processes. Teams can modernize their systems much faster than usual, therefore having no impact on business as usual.

The other key benefit is improved code quality/maintainability by using Claude Code to identify efficiency bottlenecks as well as remove technical debt while producing better structured code to make the system easier to maintain and enhance over time. Also developers will be more productive since Claude Code automates repetitive tasks and helps develop complex logic; therefore allowing engineers to spend more time on higher value work items.

Another benefit of using Claude Code while modernizing legacy systems is reducing risk during the process by providing consistent/reliable outputs and reducing human error associated with large scale transformation projects. Lastly, Claude Code enables organizations to adopt cloud-native/scalable architectures in a more seamless/cost-efficient manner since it is able to integrate with existing workflows.

Leading Companies Using Claude Code to Modernize Legacy Software

When it comes to modernizing legacy software, there are many companies working with Claude Code and utilizing AI-assisted development functionality to assist businesses shift to scalable and high performance architectures. Some of these companies who have used or are actively using Claude Code for modernization include:

1. Cleveroad

Cleveroad is a legacy software modernization company, which expertise includes modernizing existing legacy software systems by implementing new artificial intelligence-based solutions, working with cloud-native infrastructure, refactoring monolithic application architectures, providing microservices as part of an overall platform transformation process, and incorporating automated code generation into the development process.

The engineering staff at Cleveroad possesses significant experience in legacy modernization services, including but not limited to refactoring existing systems into new architectures, implementing API-based systems, and using the latest technologies to automate code generation as a means of accelerating the modernization of legacy software systems.

As an organization with a strong focus on specific industries (such as healthcare, financial technology, logistics, etc.), Cleveroad delivers innovative solutions based on the specific requirements of each client or enterprise. Furthermore, on the Clutch website, Cleveroad has received 79 reviews at an average rating of 4.9/5, representing a consistent level of satisfaction among clients and a high level of quality in delivery.

2. Thoughtworks

Thoughtworks is a global tech consultancy that has been at the forefront of new software development methods since its inception, specifically in relation to cutting-edge software engineering techniques such as AI-supported development and legacy system migration through domain-specific design or evolutionary design. They are also actively investigating LLM-based coding solutions like Claude Code within their continuous delivery systems (CDs) to shorten the time needed for projects that have undergone re-factoring and updates to be completed.

With a substantial amount of experience working with large financial institutions, retail companies, and the public sector, it is clear that Thoughtworks is focused on providing their clients with sustainable, scalable services. The consultancy has become well regarded throughout the industry and has appeared in most reports produced by Forrester Wave, as well as through some of the leading software engineering associations worldwide via their contributions to both open-source software as well as agile methodologies.

3. Endava

Endava specializes in advanced digital transformation services with a focus on upgrading outdated systems using cloud migration, automation, and AI-enhanced development processes. The company uses AI coding assistants to help teams streamline refactoring code to improve the maintainability of their systems.

Endava has a lot of experience working with financial services, payments and telecommunications and has helped many businesses transition from their old systems to modernized platforms. Endava is publicly traded and is one of the world's best engineering companies, receiving consistent recognition for being a top technology services company and enterprise client portfolio within Europe and North America.

4. Globant

Globant is redesigning legacy applications by using design combined with engineering, along with AI-based methods of development such as using generative AI tools like Claude Code as part of an agile workflow. They have the ability to quickly transform existing systems through the use of their “AI Pods” model for system transformation and optimizing codebases.

With experience in media, gaming, finance and retail, Globant has received numerous awards and recognitions, including being named one of Fast Company’s Most Innovative Companies and being recognized by Gartner based on their ability to implement digital media transformations.

5. Cognizant

Cognizant is an international IT services company that specializes in SaaS solutions for legacy systems and new applications built in the public cloud. The company believes that developing new applications requires different tools to make it easier for developers to move their software to legacy platforms. Their software engineering lifecycle combines automated tools (such as AI), automation platforms, and cloud-native architectures to create enterprise-level solutions quickly.

The company provides enterprise-level solutions to various industries, including healthcare, banking and manufacturing, using extensive industry-specific legacy-modernization frameworks. Cognizant has consistently been included on the Fortune 500 list and recognized by Gartner and IDC for its digital transformation capabilities.

6. Capgemini

Capgemini is a leader in providing enterprise technology with a focus on AI-driven solutions for major entity transformation efforts that include implementing generative AI-based applications to automate code analysis, refactoring, and re-architecting systems.

Their solutions provide an efficient method to migrate legacy systems to cloud-native platforms while delivering on current commitments. With an extensive portfolio of certifications in the automotive, financial services, and public sectors, Capgemini has been consistently ranked among the top global consulting firms through various sources, including Gartner Magic Quadrants.

7. Persistent Systems

Persistent Systems has its focus primarily on AI-powered software Engineering and modernising older software by making use of generative AI to help accelerate code migration and improve the performance of existing systems. They provide cloud migration services, API enablement and intelligent automation.

Persistent has extensive experience within the healthcare, banking and software product engineering industries. They have been featured in Forbes Asia's Best Under A Billion and have established key vendor partnerships with large cloud providers such as AWS and Microsoft Azure.

8. Grid Dynamics

Grid Dynamics works to modernize legacy systems via AI-powered solutions and modern data driven technologies. This is accomplished through using tools such as Claude Code in development pipelines, allowing for faster iterations of application enhancements (or refactorings).

They specialize in e-commerce, retail and technology platforms that deploy large scale distributed system architectures to deliver the capability needed for both transactional and operational components across multiple system environments (e.g., web-based, physical stores, etc).

The company uses an "engineering first" approach to deliver value to clients through engineering innovation, which has resulted in recognition by Gartner and other analyst firms as a leading provider of digital commerce solutions and platform engineering capabilities.

9. Softjourn

Softjourn provides customized software upgrade solutions that specialize in Fintech and Media Platforms, using AI to improve the efficiency and accuracy of software development through the use of AI based coding tools during software development.

They have a lot of experience with reengineering old systems into new ones, creating microservices, and integrating new payment systems as well as new streaming technologies into your business. Softjourn has built a great reputation with their target audiences and is highly rated on sites such as Clutch and GoodFirms for providing consistent results and technical knowledge.

10. Nagarro

Nagarro's full-stack digital engineering services include artificial intelligence (AI)-aided development tool modernization and cloud-based transformation for legacy systems; among other advanced technologies such as regenerating AI to automate code migration, enhance quality assurance/testing methodology, and increase speed of delivery.

They have expertise in sectors such as automotive, retail, and logistics by providing enterprise-grade solutions that go beyond standard business practices and provide an enterprise-grade approach. Nagarro shares their technical know-how to the public via stock market listings, and has received numerous awards for innovation and effectiveness based on their performance ratings across many categories including global IT service provider rankings and digital engineering reports.

Final Thoughts

The adoption of tools such as Claude Code is rapidly changing how organizations are tackling legacy modernization today. The organizations mentioned above show a high degree of ability in utilizing their combined expertise (AI-assisted development, Domain Expertise, Proven Engineering practices) to produce scalable and future-proof systems.