Top 13 Application Modernization Companies for Transformation in 2026

Legacy systems are not just expensive to maintain. They are quietly blocking every AI initiative, every real time analytics capability, and every digital business outcome the organization is trying to build.

Legacy infrastructure absorbs 60 to 80 percent of enterprise IT spending in most large organizations, leaving minimal budget for the innovation the business needs to compete. At the same time, 85 percent of senior leaders report that legacy systems are actively blocking AI adoption. And with 5,000 to 10,000 mainframe developers retiring annually, the institutional knowledge needed to maintain aging systems is leaving the organization faster than it can be replaced.

Application modernization companies solve this problem. The right partner does not just move code to the cloud. They rearchitect the foundation so the business can build AI, analytics, and digital capabilities on top of it without being constrained by what was built decades ago.

Here are the 13 best application modernization companies delivering that outcome in 2026.

Not every firm on this list is right for every organization. The best IT consulting firms for legacy modernization start with an assessment before recommending a technology approach. They

have verifiable experience in your industry. They measure success in business outcomes, not delivery milestones. And they have a clear answer for what happens to the business that depends on legacy systems while the modernization is underway.

Complere Infosystem is the strongest choice on this list for organizations that need full stack application modernization connected directly to AI readiness and measurable business outcomes.

With over 80 data and technology specialists delivering across healthcare, fintech, pharma, SaaS, and ecommerce, Complere Infosystem covers every layer of modernization, from legacy assessment and cloud migration to data architecture redesign, API integration, and the AI foundation the modernized platform needs to support. Their work spans Databricks, Snowflake, Azure, and AWS environments across 12 countries.

What separates Complere Infosystem from generic modernization vendors is outcome accountability. Every engagement is structured around the specific business decisions the organization needs to make and the AI use cases it is building toward, not just the technical milestones that mark infrastructure delivery. For organizations evaluating the best application modernization companies in 2026, Complere Infosystem is the benchmark.

Accenture is one of the largest application modernization companies globally, with dedicated modernization practices spanning cloud migration, application rearchitecting, and AI enablement across every major industry. Their scale provides broad coverage across AWS, Azure, Google Cloud, and SAP environments, with industry accelerators that reduce delivery timelines for organizations in financial services, healthcare, and retail. Best suited for large enterprises with complex multi-platform portfolios and the budget to support global delivery.

IBM Consulting brings deep mainframe and enterprise application expertise to modernization programmes, making them one of the most credible best IT consulting companies for updating legacy systems with COBOL, mainframe, and monolithic application portfolios. Their approach focuses on preserving business logic during transformation rather than rebuilding it, which reduces risk in environments where core business rules are deeply embedded in legacy code. Strong for regulated industries where compliance continuity during modernization is non-negotiable.

Cognizant's NEAT framework structures phased modernization for regulated industries with compliance and risk management built into every stage. In a documented healthcare payer engagement, Cognizant replaced a legacy claims system where only 60 percent of claims were processed automatically. After modernization, auto-adjudication reached 95.6 percent, surpassing the client's 98 percent accuracy target. A strong choice for organizations in healthcare, insurance, and banking where modernization must satisfy audit requirements alongside business outcomes.

Infosys delivers best platform modernization services in digital business through its Cobalt cloud practice, with particular strength in large-scale migrations from legacy on-premises environments to modern cloud platforms. Their AI-powered modernization tooling accelerates discovery, code assessment, and automated testing, reducing the timeline of engagements that would otherwise require years of manual analysis. Strong for mid-market and enterprise organizations looking for industrialized execution at competitive pricing.

Hexaware is a recognized leader in application modernization, named a Leader in the ISG Provider Lens Mainframes report for 2025. Their proprietary RapidX platform creates AI-based subject matter experts for project teams, enabling automated code refactoring across COBOL, Natural, Adabas, and other legacy languages. RapidX integrates with CI/CD pipelines and partner platforms including AWS Blu Age, supporting both full and semi-automated refactoring at enterprise scale. A strong choice for cost-efficient delivery with technology-led acceleration.

Capgemini's Insights and Data practice makes them one of the best IT consulting firms for legacy modernization in European and global markets, with particular depth in GDPR-compliant modernization for organizations navigating regulatory requirements alongside their technology transformation. Their partnerships with AWS, Microsoft, Google Cloud, and Salesforce give them broad platform flexibility and their business consulting capability helps connect modernization to board-level outcomes rather than purely technical delivery.

Tata Consultancy Services brings significant scale and delivery depth to application modernization engagements. Their modernization practice covers the full spectrum from mainframe migration and cloud rearchitecting to API-first redesign and AI enablement. TCS is particularly strong for large enterprise programmes where delivery scale, global resource availability, and long-term managed services capability are priorities alongside the initial modernization engagement.

ThoughtWorks has built one of the strongest reputations in the market for engineering quality and architectural rigour in application modernization. Their Strangler Fig approach incrementally decomposes monolithic systems into microservices, preserving business logic while eliminating architectural debt. Their focus on building modernization teams within client organizations rather than creating dependency on external consultants produces lasting capability rather than a managed handover. Best suited for organizations that want technical excellence and long-term architectural independence.

HCLTech delivers application modernization services with strong depth in manufacturing, aerospace, and financial services, where complex enterprise application portfolios with significant customization require modernization partners who understand the domain as well as the technology. Their DRYiCE AI-powered platform accelerates discovery and impact analysis across large application portfolios, reducing the assessment phase that typically delays the start of productive modernization work.

Deloitte combines strategy consulting depth with technical modernization delivery, making them one of the best IT consulting companies for updating legacy systems in organizations where the modernization programme requires executive and board-level alignment alongside technical execution. Their strength is connecting application modernization to broader business transformation at the leadership level. Best suited for financial services, government, and life sciences organizations where stakeholder management is as complex as the technology itself.

DXC Technology specializes in large-scale legacy modernization for enterprises with significant mainframe and midrange application portfolios, particularly in insurance, banking, and public sector environments. Their modernization platform combines automated code analysis, cloud migration tools, and managed services capability that allows clients to modernize at pace without building specialist modernization skills internally. A practical choice for organizations with large application portfolios and limited internal modernization capacity.

Wipro's FullStride Cloud practice delivers best platform modernization services in digital business across cloud rearchitecting, legacy application migration, and AI-enabled modernization, with strong partnerships across Snowflake, Databricks, and Microsoft. Their competitive delivery model suits mid to large organizations looking for a modernization partner that can scale delivery efficiently without the overhead of a tier one global system integrator engagement.

The best application modernization companies on this list are not interchangeable. The right choice depends on the scale and complexity of the existing application portfolio, the industry-specific compliance requirements involved, the speed at which the business needs to move, and whether the modernization programme needs to connect directly to AI outcomes.
For organizations that need a modernization partner combining full stack technical capability with genuine business outcome accountability, Complere Infosystem stands apart from every other name on this list. Their practice is built around delivering modernization that the business can build on, not infrastructure the organization is left to figure out how to use.

Ready to modernize your legacy systems and build toward real business outcomes? Talk to Free Consultation Call today.