Most companies searching for legacy software modernization companies did not set out to build a legacy system. What happens instead is that something works. A platform, a database, a set of spreadsheets and manual steps that hold the operation together. It works for five years, then ten, then fifteen. The people who built it move on. The documentation stops matching reality. And one day the question stops being "how do we improve this" and becomes "what happens if this breaks."
That is the real reason companies start looking for a modernization partner. Not ambition. Risk. The system that used to be an asset has quietly become the single point of failure the business runs on.
Choosing who to hand that system to is a bigger decision than most vendor selections, because the hard part of legacy modernization is not writing new code. It is understanding why the old code does what it does, and making sure that knowledge does not disappear again the moment the project closes. This list breaks down 24 firms working in legacy modernization in 2026, with the details that actually matter when you are comparing them.
The 24 Companies at a Glance
ISU Corp
ScienceSoft
TSRI
Thoughtworks
EPAM Systems
IBM Consulting
Accenture
Kyndryl
Capgemini
Cognizant
Infosys
HCLTech
Wipro
DXC Technology
Endava
SoftServe
Persistent Systems
Smartbridge
Simform
BairesDev
Corsac Technologies
Leobit
Innowise
Devox Software
How We Evaluated These Companies
This is not a ranking by revenue, headcount, or brand recognition. If it were, the order would be obvious and useless, because the largest firm on this list is not the right answer for a 300-person insurance administrator with a 20-year-old claims platform.
Companies were assessed against five criteria, weighted toward what established mid-market and enterprise organizations in regulated industries actually need:
Depth of legacy stack experience. Specific, demonstrated work in the languages and architectures that are actually failing in the field, not a generic list of modern technologies.
Regulated industry track record. Verifiable delivery in insurance, healthcare, financial services, government, manufacturing, or lab science, where compliance and auditability are constraints rather than features.
Continuity after launch. What happens once the new system is live. Firms that hand off and leave were assessed differently from firms that retain the system knowledge and stay accountable for it.
Fit for established organizations. Suitability for companies with existing operations, real users, and real revenue running on the system, as distinct from startups building a first product.
Verifiable outcomes. Named clients, published case studies, and long-running relationships rather than unattributed claims.
Company data was verified against each firm's own published figures and cross-checked against public company records. Figures reflect the most recent available reporting.
1. ISU Corp
Legacy Stacks: VB6, VB.NET, .NET Framework, Classic ASP, Microsoft Access, legacy SQL Server, Delphi, monolithic line-of-business applications, and spreadsheet-driven manual workflows
Modern Substitutes: .NET Core, C#, Angular, React, TypeScript, Azure, SQL Server, REST APIs, microservices architecture, Power BI
Cost per Hour: Undisclosed. Project-based engagements, quoted after a discovery process
Company Size: A core team of 40 senior-level professionals, scaling through a technology partner network as project skill sets require
Founded: 2005
Headquarters: Kitchener-Waterloo, Ontario, Canada
Key Markets: Canada and the United States
Best For: Established organizations in regulated industries that want a long-term software partner, whether that starts with a full modernization program or a single system that has become a risk
ISU Corp has spent more than twenty years modernizing legacy software systems that organizations cannot afford to lose. The firm was founded in 2005 in Kitchener-Waterloo, Ontario, and works almost entirely with established organizations in insurance, government, healthcare, financial services, manufacturing, and lab science.
What separates ISU Corp from most of the firms on this list is the operating model. Rather than delivering a project and handing over a repository, ISU Corp runs a fully managed model, absorbing the institutional knowledge of how a client's systems actually work so that operations never depend on a single person remaining employed. That knowledge is held by the firm, not by an individual developer, helping ensure the modernized system never becomes dependent on a single person the way the original system often did.
Rather than staffing projects with large teams of junior developers, ISU Corp relies on a senior team of architects and engineers who specialize in complex legacy systems: 40 software architects, project managers, engineers, and developers, all with direct experience in the industries ISU Corp serves, scaling through a partner network when a project calls for a specific skill set. On a legacy system with undocumented business rules, the person doing the archaeology is the entire project. A smaller senior team is not a limitation on this kind of work; it is the reason the discovery phase produces a roadmap rather than a guess.
The result is unusually long client relationships. ISU Corp has worked with Labstat, part of Certified Group, for over twelve years, and with OTIP Insurance for ten. The Ontario College of Teachers runs two active platforms built and maintained by ISU Corp. RWAM Insurance Administrators runs an ISU Corp platform that uses AI to automate claims processing. Earlier enterprise work includes Bell, GE, and Manulife, and the firm has been recognized with multiple industry awards for its delivery model.
Most of those relationships did not begin with a large project. Several of ISU Corp's longest client partnerships started as a single fix, integration, or stabilization initiative before expanding into modernization, ongoing maintenance, or additional software projects as trust was established.
Typical engagements start with a system that has become a risk: an unsupported platform, a vendor that has disappeared, a developer who has retired, an ERP that no longer talks to the applications built around it, or a manual process that no longer scales. Alongside full modernization programs, ISU Corp handles ERP integration, AI and automation built into business processes where it removes real manual work, codebase audits and stabilization, technical debt reduction, and ongoing production support for teams that need senior capacity without hiring for it.
Work is delivered in phases so the existing system keeps running throughout. While many clients continue working with ISU Corp for ongoing software maintenance and support after modernization, others engage the team for standalone modernization projects or targeted initiatives as their needs evolve.
2. ScienceSoft
Legacy Stacks: .NET Framework, PowerBuilder, C++, Delphi, COBOL, Visual Basic, outdated Java, legacy Sybase and Oracle databases
Modern Substitutes: .NET Core, modern Java, Microsoft Azure, AWS, PostgreSQL, MySQL, microservices architecture
Cost per Hour: Undisclosed. Estimates available through their IT project cost calculator
Company Size: Approximately 750 to 850 employees
Founded: 1989
Headquarters: McKinney, Texas, United States
Key Markets: United States, European Union, Gulf Cooperation Council
Best For: Healthcare and financial services organizations with strict compliance requirements
ScienceSoft has modernized software across more than 30 industries since 1989, with particularly deep experience in healthcare and financial services. That focus has produced real compliance expertise, including HIPAA, HITECH, and GDPR, along with ISO 9001, ISO 27001, and ISO 13485 certification.
Their modernization work leans heavily on database migration and incremental enhancement rather than wholesale replacement, and they hold partnerships with Oracle, Microsoft, and AWS. At roughly 800 people they are large enough to staff substantial programs while remaining more accessible than the global integrators.
3. TSRI
Legacy Stacks: COBOL, Fortran, JCL, Ada, PL/1, CA-IDEAL, Assembly, and over 35 legacy languages
Modern Substitutes: Java, C#, C++, .NET Core, modern relational databases, AWS and Azure
Cost per Hour: Undisclosed. Project-based pricing
Company Size: Approximately 50 employees
Founded: 1995
Headquarters: Kirkland, Washington, United States
Key Markets: United States, with a strong concentration in federal and defense
Best For: Organizations with mainframe or scientific systems written in languages the market has largely abandoned
TSRI is the most specialized firm on this list. Since 1995 they have focused exclusively on automated modernization of mission-critical legacy systems, using a proprietary transformation platform that combines deterministic and generative AI to convert code between languages at high accuracy.
Their portfolio skews toward systems where failure is not an option: air traffic control, aircraft avionics, Department of Defense platforms, and large financial applications, including classified work. If your problem is a mainframe in a language almost nobody writes anymore, TSRI has probably converted one like it.
4. Thoughtworks
Legacy Stacks: COBOL, PL/I, Java monoliths, legacy enterprise platforms, tightly coupled architectures
Modern Substitutes: Java, Kotlin, Python, TypeScript, Rust, microservices, cloud-native platforms, CI/CD pipelines
Cost per Hour: Approximately $150 to $350
Company Size: Over 10,000 employees across 47 offices in 18 countries
Founded: 1993
Headquarters: Chicago, Illinois, United States
Key Markets: United States, Canada, United Kingdom, Germany, India, Australia, China, Brazil
Best For: Enterprises that want engineering practice change alongside the technical migration
Thoughtworks has an outsized influence on how the industry approaches modernization. Their chief scientist, Martin Fowler, co-authored the Agile Manifesto and originated much of the vocabulary practitioners use for incremental legacy migration, including the strangler fig pattern.
They focus on enterprise platform modernization delivered incrementally, and typically change how a client's own engineering organization works as part of the engagement. That is a strength if you want the capability transferred, and a cost if you simply want the system fixed. The firm was taken private in 2024.
5. EPAM Systems
Legacy Stacks: Mainframe systems, legacy web applications, monolithic enterprise platforms, outdated Java and .NET
Modern Substitutes: Cloud-native architectures, microservices, Java, .NET Core, Kubernetes, AWS and Azure
Cost per Hour: Approximately $150 to $350
Company Size: Approximately 61,000 employees
Founded: 1993
Headquarters: Newtown, Pennsylvania, United States
Key Markets: North America, Europe, Asia-Pacific
Best For: Large organizations running multi-year platform modernization programs
EPAM combines engineering scale with its own tooling, including the Maestro hybrid cloud management platform and a dedicated suite for platform modernization. Their approach starts with analysis of the existing system to identify which operational components are genuinely essential before deciding what gets rebuilt, replatformed, or retired.
Strong in financial services, life sciences and healthcare, and software and technology. At 61,000 people they operate at true enterprise scale while retaining a reputation for engineering depth.
6. IBM Consulting
Legacy Stacks: COBOL, PL/I, JCL, CICS, IMS, RPG and AS/400, IBM Z mainframe environments
Modern Substitutes: Java, Red Hat OpenShift, microservices, hybrid cloud architectures, API encapsulation layers
Cost per Hour: Approximately $150 to $400
Company Size: Approximately 160,000 consultants
Founded: 1991, rebranded from IBM Global Business Services in 2021. Parent company IBM founded 1911
Headquarters: Armonk, New York, United States
Key Markets: Worldwide
Best For: Organizations running IBM mainframe workloads they intend to keep rather than replace
Nobody understands IBM mainframes better than IBM. For organizations running COBOL on IBM Z, that matters more than any other consideration, and IBM Consulting's approach reflects it: API encapsulation to expose mainframe functionality to modern applications, selective migration to Red Hat OpenShift, and hybrid architectures where the mainframe stays in place.
Supporting products including IBM Instana Observability and IBM Turbonomic give visibility into how modernized workloads actually behave in production. The trade-off is the one you would expect: deep alignment with the IBM ecosystem.
7. Accenture
Legacy Stacks: Mainframe COBOL, SAP ECC, Oracle Forms, .NET Framework, monolithic enterprise architectures
Modern Substitutes: Java, .NET Core, SAP S/4HANA, AWS, Azure, Google Cloud, Docker, microservices
Cost per Hour: Undisclosed. Enterprise engagements, custom quote
Company Size: Approximately 779,000 employees
Founded: 1989 as Andersen Consulting, fully independent as Accenture in 2001. Roots trace to Arthur Andersen's consulting division in 1951
Headquarters: Dublin, Ireland
Key Markets: Worldwide, operating in more than 120 countries
Best For: Global enterprises modernizing many systems at once with dedicated internal change management
Accenture is the largest professional services firm in the world and approaches modernization as one part of a broader transformation program, weighing financial return and strategic business value alongside the technical work. Engagements typically bundle cloud infrastructure, AI, and risk management, and often include reskilling a client's internal teams.
The scale is the offer and also the caveat. Accenture is built for programs that span business units and geographies. Organizations with a single critical system and no internal program office generally find the engagement model heavier than the problem requires.
8. Kyndryl
Legacy Stacks: COBOL, CICS, RPG, IMS, AS/400, mainframe and distributed infrastructure
Modern Substitutes: Microsoft Azure, AWS, Google Cloud, Java, containerized workloads
Cost per Hour: Undisclosed. Contract pricing based on scope
Company Size: Approximately 73,000 employees across more than 60 countries
Founded: 2021, spun off from IBM's Global Technology Services division
Headquarters: New York, New York, United States
Key Markets: United States, Canada, Europe, Japan, Australia
Best For: Organizations that want infrastructure modernization and ongoing managed operations from the same provider
Kyndryl inherited IBM's managed infrastructure business and, with it, roughly 4,400 enterprise clients including a large share of the Fortune 100. Their modernization work starts by reverse engineering the existing system to determine which functions justify updating, with cybersecurity and regulatory compliance treated as primary constraints.
Because the business was built around long-term managed services rather than project delivery, continuity after go-live is structurally part of the model. Kyndryl has undergone several rounds of workforce reduction since the spin-off, which is worth understanding when evaluating long-term account stability.
9. Capgemini
Legacy Stacks: COBOL, mainframe environments, legacy ERP platforms, monolithic enterprise applications
Modern Substitutes: Java, TypeScript, Node.js, cloud-native architectures, microservices
Cost per Hour: Undisclosed. Fixed contracts scaled to project size
Company Size: Approximately 423,000 employees
Founded: 1967
Headquarters: Paris, France
Key Markets: France, Germany, United Kingdom, United States, Canada, and worldwide
Best For: European and North American enterprises wanting a structured, methodology-driven assessment before committing
Capgemini is unusual in explicitly balancing AI coding agents against human analysis rather than leading with automation. Their approach uses AI to accelerate discovery and code analysis while keeping architectural judgment with engineers, which tends to produce more conservative and more defensible migration plans.
Nearly sixty years old and heavily represented in European public sector and financial services work, where documented process matters as much as delivery speed.
10. Cognizant
Legacy Stacks: COBOL, PL/1, ABAP, IMS, DB2, older C++, mainframe environments
Modern Substitutes: Java, Python, Node.js, NoSQL and cloud-native databases, microservices
Cost per Hour: Approximately $65 to $250
Company Size: Approximately 350,000 employees across more than 40 countries
Founded: 1994
Headquarters: Teaneck, New Jersey, United States
Key Markets: United States, Canada, United Kingdom, India
Best For: Healthcare payers and financial services firms modernizing at scale
Cognizant's modernization practice is strongest in healthcare and financial services, reinforced by their acquisition of TriZetto, which gave them deep exposure to healthcare payer systems specifically.
Their delivery model runs the legacy system in parallel while new code is tested, migrating in stages to keep disruption low. Onshore, nearshore, and offshore capacity is blended within a single engagement, which is the main lever behind their pricing range.
11. Infosys
Legacy Stacks: COBOL, ABAP, Visual Basic, mainframe systems, legacy ERP
Modern Substitutes: Java, AWS, Azure, microservices, cloud-native data platforms
Cost per Hour: Undisclosed. Fixed contract pricing
Company Size: Approximately 330,000 employees
Founded: 1981
Headquarters: Bengaluru, India
Key Markets: North America, Europe, Asia-Pacific
Best For: Large enterprises prioritizing predictable fixed-price delivery on well-defined scope
Infosys targets outdated infrastructure as the primary problem and cloud migration as the primary answer, supported by their own modernization tooling and a strong preference for phased delivery that limits disruption.
Their fixed-price contracting is genuinely useful when scope is well understood and genuinely constraining when it is not. Discovery quality determines how well an Infosys engagement goes.
12. HCLTech
Legacy Stacks: COBOL, Natural and ADABAS, PL/1, C++, mainframe environments
Modern Substitutes: Java, C#, SAP S/4HANA, cloud platforms, containerized services
Cost per Hour: Approximately $60 to $150
Company Size: Approximately 223,000 employees across 60 countries
Founded: 1991, spun out of HCL Group, founded 1976
Headquarters: Noida, India
Key Markets: North America, Europe, Asia-Pacific
Best For: Manufacturing and engineering organizations with large distributed application estates
HCLTech assesses each application individually before selecting a modernization path, choosing between rehosting to the cloud, replatforming with code changes, and full refactoring for future extensibility. That per-application triage is well suited to organizations with hundreds of applications rather than one critical system.
Notably strong in engineering and R&D services, and they run a continuous modernization model with several long-term clients rather than treating modernization as a finite project.
13. Wipro
Legacy Stacks: Mainframe COBOL, JSP, AngularJS, legacy Java applications, monolithic architectures
Modern Substitutes: React, Angular, modern Java, AWS and Azure, cloud-native services
Cost per Hour: Approximately $50 to $150
Company Size: Over 240,000 employees across 65 countries
Founded: 1945 as Western India Vegetable Products, entering IT services in the 1980s
Headquarters: Bengaluru, India
Key Markets: North America, Europe, Asia-Pacific
Best For: Cost-sensitive enterprises modernizing large application portfolios
Wipro's application modernization practice centers on rewriting, rehosting, and re-engineering code so existing systems work with newer technology, with a strong bias toward cloud-based delivery for ongoing supportability.
They use automation aggressively to hold costs down, which makes them competitive on price for high-volume portfolio work. Their acquisition of Capco gave them meaningful additional depth in financial services.
14. DXC Technology
Legacy Stacks: Mainframe COBOL and CICS, AS/400, .NET Framework, ASP.NET Web Forms, VB.NET, monolithic architectures
Modern Substitutes: Java, .NET Core, AWS, Azure, microservices, containerized workloads
Cost per Hour: Undisclosed. Enterprise engagements, custom quote
Company Size: Approximately 125,000 employees
Founded: 2017, from the merger of Computer Sciences Corporation and HPE Enterprise Services
Headquarters: Ashburn, Virginia, United States
Key Markets: Worldwide
Best For: Aerospace, defense, and insurance organizations with critical workloads under regulatory oversight
DXC administers critical workloads for large enterprises worldwide, with particular depth in aerospace and defense, insurance, and financial services. Their inherited CSC and EDS lineage means genuinely deep mainframe and legacy infrastructure experience.
Security, transparency, and operational continuity are the pillars of how they position modernization work, which fits organizations where an outage carries regulatory consequences rather than just revenue impact.
15. Endava
Legacy Stacks: Legacy payments platforms, Java monoliths, .NET Framework, tightly coupled enterprise integrations
Modern Substitutes: Java, .NET, React, Azure, AWS, microservices, event-driven architectures
Cost per Hour: Approximately $75 to $150
Company Size: Approximately 10,400 employees
Founded: 2000
Headquarters: London, United Kingdom
Key Markets: United Kingdom, Europe, North America
Best For: Payments, banking, and insurance firms modernizing transaction-critical platforms
Endava is heavily concentrated in payments and financial services, which shows in how they approach modernization: transaction integrity and regulatory compliance drive the sequencing rather than technical elegance.
Their Dava.X practice focuses specifically on converting legacy estates into a modern digital core, and they use data analysis to prioritize which components move first. Also active in telecommunications, media, mobility, and healthcare.
16. SoftServe
Legacy Stacks: Progress ABL, Fortran, legacy .NET and Java applications, monolithic architectures
Modern Substitutes: Cloud-native platforms, microservices, Google Cloud, AWS, Azure, Kubernetes
Cost per Hour: Approximately $100 to $150
Company Size: Over 10,000 employees across 58 offices in 14 countries
Founded: 1993
Headquarters: Austin, Texas, United States, with European headquarters in Lviv, Ukraine
Key Markets: United States, Canada, United Kingdom, Germany, Poland
Best For: Organizations wanting cloud-native rebuilds with strong data and analytics capability
SoftServe uses an AI architect agent trained on outdated systems and languages to identify domain boundaries and recurring patterns before modernization begins, which shortens the discovery phase considerably on large codebases.
Their database and security work is a genuine strength, reducing the exposure that older data layers typically carry. Dual headquarters in Austin and Lviv gives them both North American account management and substantial European engineering capacity.
17. Persistent Systems
Legacy Stacks: Legacy enterprise applications, monolithic architectures, outdated data platforms
Modern Substitutes: Python, Java, microservices, AWS and Azure, low-code migration tooling
Cost per Hour: Undisclosed. Project-based pricing
Company Size: Approximately 24,000 employees
Founded: 1990
Headquarters: Pune, India
Key Markets: United States, India, Australia, New Zealand
Best For: Software companies and technology-led organizations modernizing product platforms
Persistent Systems Limited focuses on shortening modernization timelines through low-code and no-code migration tooling that automates much of the repetitive conversion work. Their specialty is decomposing monolithic systems into independently updatable services.
Note that a separate, unrelated company called Persistent Systems LLC operates in aerospace and defense communications from New York. The modernization firm is Persistent Systems Limited, headquartered in Pune.
18. Smartbridge
Legacy Stacks: Legacy ERP including Oracle JD Edwards, .NET Framework, ASP.NET Web Forms, VB.NET, monolithic architectures
Modern Substitutes: Azure, AWS, .NET Core, Node.js, Java, Python, Power Platform
Cost per Hour: Approximately $150 to $199
Company Size: Approximately 50 to 249 employees
Founded: 2003
Headquarters: Houston, Texas, United States
Key Markets: United States
Best For: Energy, manufacturing, and restaurant operators modernizing around an existing ERP
Smartbridge assesses the existing application and its remaining useful life before recommending a path, which is a more honest starting point than firms that assume replacement. Strong in intelligent automation, data and analytics, and ERP-adjacent modernization.
Their concentration in energy and manufacturing, both heavily represented in the Houston market, gives them practical experience with operational systems that cannot pause for a migration.
19. Simform
Legacy Stacks: ColdFusion, ASP.NET Web Forms, .NET Framework, VB.NET, Delphi, FoxPro, COBOL, monolithic architectures
Modern Substitutes: Node.js, Python, Java, PHP, Ruby, AWS, Azure, Google Cloud Platform
Cost per Hour: Approximately $25 to $49
Company Size: Approximately 1,000 employees
Founded: 2010
Headquarters: Orlando, Florida, United States, with delivery from Ahmedabad, India
Key Markets: United States, Canada, United Arab Emirates, India
Best For: Mid-market companies modernizing on a constrained budget
Simform handles enterprise system modernization in logistics, fintech, and healthcare, restructuring systems while limiting operational disruption. Platform and cloud migration are the core services, with a focus on making systems scalable after the fact.
Their pricing is among the lowest on this list, which reflects an offshore-weighted delivery model. That is a real cost advantage and a real consideration for time zone overlap and knowledge continuity.
20. BairesDev
Legacy Stacks: ASP.NET, COBOL, legacy PHP, monolithic architectures
Modern Substitutes: Java, Python, Node.js, React, AWS, Azure, microservices
Cost per Hour: Approximately $50 to $99
Company Size: Approximately 4,000 employees
Founded: 2009
Headquarters: San Francisco, California, United States, with delivery across Latin America
Key Markets: North America, Europe, Latin America
Best For: North American companies wanting time zone aligned engineering capacity at scale
BairesDev runs a structured migration process spanning assessment, analysis, rehosting, refactoring, and integration, with cloud compatibility and performance improvement as the stated priorities.
Their main differentiator is a large Latin American engineering bench working in North American business hours, which removes much of the coordination overhead that comes with offshore delivery. Their model leans toward staff augmentation more than full ownership of outcomes.
21. Corsac Technologies
Legacy Stacks: FoxPro, Delphi, ColdFusion, AngularJS, .NET Framework, ASP.NET Web Forms, VB.NET, Xamarin, COBOL, monolithic systems
Modern Substitutes: .NET Core, Angular, Blazor and WebAssembly, .NET MAUI, TypeScript, ASP.NET Core MVC, microservices, Power BI and Tableau
Cost per Hour: Undisclosed
Company Size: Approximately 50 to 100 employees
Founded: Sources vary between 2007 and 2018
Headquarters: Toronto, Ontario, Canada
Key Markets: United States, Canada
Best For: Companies with Microsoft stack applications built on now-unsupported frameworks
Corsac Technologies specializes in the Microsoft legacy stack, particularly FoxPro, Delphi, ColdFusion, and older .NET Framework applications, transitioning them to .NET Core and modern front-end frameworks. Their published service catalogue is unusually specific about migration paths.
They work with minimal involvement from the client's internal team, which suits organizations whose developers cannot be pulled off day-to-day operations.
22. Leobit
Legacy Stacks: WinForms, WCF, VB.NET, Delphi, legacy ASP.NET applications
Modern Substitutes: .NET Core, ASP.NET Core, C#, Azure, Angular, React, Vue, Blazor, TypeScript, Entity Framework, microservices
Cost per Hour: Approximately $25 to $49
Company Size: Approximately 250 employees
Founded: 2014
Headquarters: Lviv, Ukraine, with delivery across Ukraine and Poland
Key Markets: United States and Western Europe
Best For: Companies needing .NET modernization plus UI and UX redesign in one engagement
Leobit works as a technology advisor across the full lifecycle, from initial assessment through maintenance and support, and adapts the engagement model to each client rather than imposing a fixed process.
Their in-house design studio handles UX consulting, discovery, prototyping, and testing, which matters more than it sounds: legacy modernization frequently fails on user adoption rather than technical delivery.
23. Innowise
Legacy Stacks: Legacy .NET and Java applications, ASP.NET Web Forms, VB.NET, monolithic architectures
Modern Substitutes: AWS, Microsoft Azure, Google Cloud, Docker, Kubernetes, microservices
Cost per Hour: Approximately $50 to $99
Company Size: Approximately 2,000 employees
Founded: 2007
Headquarters: Warsaw, Poland, with delivery across Poland, Lithuania, Germany, and Ukraine
Key Markets: United States, United Kingdom, Western Europe
Best For: Companies with large existing systems that need substantial engineering capacity quickly
Innowise offers full-cycle delivery from consulting and strategy through post-launch support, with an explicit focus on eliminating the specific problems legacy systems create: vendor lock-in, escalating maintenance costs, siloed data, and inefficient workflows.
Their scale allows them to staff large programs quickly. As with most European delivery-centre firms, evaluate how account continuity is maintained across a team of that size.
24. Devox Software
Legacy Stacks: .NET Framework, ASP.NET Web Forms, VB.NET, legacy JavaScript, monolithic architectures
Modern Substitutes: .NET, Java, Python, React, Vue, Node.js, Angular, cloud platforms
Cost per Hour: Approximately $50 to $99
Company Size: Approximately 80 to 100 employees
Founded: 2018
Headquarters: Miami, Florida, United States, with delivery from Warsaw, Poland and Kyiv, Ukraine
Key Markets: United States, United Kingdom, European Union
Best For: Manufacturing and logistics companies wanting AI-accelerated code analysis on large codebases
Devox Software rebuilds outdated systems while addressing the security exposure, vendor dependency, and workflow bottlenecks that come with them. Their AI Solution Accelerator is used to speed up code analysis, refactoring, and test generation on legacy codebases.
They report that a large majority of clients stay with them beyond two years, which is a meaningful signal for a firm founded as recently as 2018.
How to Choose the Right Legacy Modernization Partner
The starting point is not the vendor list. It is an honest description of your own problem: what specifically is at risk, how long you have before it becomes urgent, and what happens to the business if the system stops. A firm that has solved your exact problem before is worth more than a firm with a longer technology list.
Beyond that, six things separate partners who work out from partners who do not.
1. Relevant industry and system experience
Ask for case studies involving your system type and your regulatory environment, not just your industry vertically. A firm that has modernized an insurance claims platform understands things about your project that a firm with general enterprise experience does not.
2. A phased approach that keeps operations running
Look for phased migration, parallel running of old and new systems, and documented rollback options. A partner who proposes a single cutover for a system your operations depend on is telling you something about their risk tolerance.
3. Compliance and security depth
Confirm demonstrated compliance with the standards that apply to you, whether HIPAA, GDPR, SOC 2, PIPEDA, or ISO 27001. Ask about encryption at rest and in transit, access control, and how they handle security review during migration rather than after it.
4. Transparent, staged cost structure
Expect a detailed estimate before work begins and a clear explanation of what changes the number. Be cautious of both ends: quotes far below the market usually mean scope has been underestimated, and quotes with no stated assumptions usually mean the assumptions are unfavorable to you.
5. Architecture that survives the next decade
The system you build now becomes the legacy system someone inherits later. Ask how the proposed architecture handles change: whether components can be updated independently, whether the data model can evolve, and whether the documentation will be usable by someone who was not there.
6. What happens after go-live, and who holds the knowledge
This is the criterion most buyers underweight and later regret. Modernization does not end at launch. Ask directly: who maintains this in year three, does the knowledge live with the firm or with one developer, and what does the support arrangement actually cover.
The reason so many organizations end up back where they started is that the second system was built the same way as the first, by people who left. A partner who retains institutional knowledge about your platform is buying you something more valuable than clean code. If ongoing ownership matters more to you than the build itself, evaluate partners on their software maintenance and support model before you evaluate them on delivery.
What Legacy Software Modernization Costs
Hourly rates across the firms on this list run from roughly $25 to over $400. That spread tells you almost nothing useful, because rate is one of the weakest predictors of what a modernization project actually costs.
What drives the number is how much of your system nobody currently understands. A well-documented application with clean separation between logic and data can be estimated accurately in a few weeks. A twenty-year-old platform with business rules buried in stored procedures, three abandoned integrations, and no surviving specification will absorb a large share of the budget before a single line of new code is written. That discovery work is unavoidable, and firms that skip it produce quotes that move.
Rough ranges by project scope
These are directional ranges for North American buyers, useful for internal budgeting rather than for comparing bids. Every one of them moves substantially with system complexity and compliance requirements.
A single integration, audit, or stabilization job. Often weeks rather than months. Frequently the right first step, and frequently how a longer partnership begins.
Single application, well understood, limited integrations. Typically a few months of work. Often the right scope when one component carries most of the risk.
Core platform modernization, phased, several integrations. Usually a multi-quarter program. This is where most established mid-market organizations land.
Full core system replacement across an enterprise. Multi-year, and generally only justified when the existing platform cannot be extended at all.
Ongoing support and maintenance after go-live. Usually quoted as a monthly retainer, and typically a meaningful fraction of annual IT spend for a system the business depends on.
Rate ranges by vendor type
Global integrators. Roughly $150 to $400 per hour. Built for enterprise-wide programs with client-side program management in place.
Specialist modernization firms and North American consultancies. Roughly $100 to $200 per hour. Usually the closest fit for a single critical platform.
Nearshore and offshore delivery firms. Roughly $25 to $99 per hour. Real cost advantage, with time zone overlap and knowledge continuity as the trade-offs to evaluate.
The number that actually matters
Compare any quote against what the current system already costs you. That figure is usually larger than organizations expect once you include license and support fees for unsupported software, staff hours spent on manual workarounds, the internal cost of the one or two people who are the only ones who understand it, delayed initiatives the system cannot support, and the realistic cost of an outage or a failed audit.
Be cautious at both ends of a bid range. A quote well below market usually means scope has been underestimated and will be revised. A quote with no stated assumptions usually means the assumptions are not in your favor. The most useful thing a prospective partner can give you before you commit is a paid, fixed-price system audit that produces a real roadmap, whether or not you continue with them.
Common Legacy System Modernization Solutions
Modernization is not one activity. Which of these applies depends entirely on what is actually wrong with your system, which is why any competent partner will assess before recommending.
Legacy application audit and strategy
A structured evaluation of technical debt, hidden dependencies, security exposure, and business-critical logic, producing a sequenced roadmap. This should always come first. Any firm that recommends an approach before auditing the system is guessing.
Rehosting and replatforming
Moving an application to modern infrastructure with limited code change, or making targeted changes so it runs properly on a modern platform. Often the fastest route to reducing risk when the application logic itself is still sound.
Decomposition into services
Breaking a monolithic system into independently deployable components so individual parts can be updated without touching the whole. This is what makes a system maintainable long-term rather than merely current.
Database and data layer modernization
Migrating from aging or unsupported database platforms, consolidating duplicated data, and improving how information is stored, processed, and shared. Frequently where the largest security exposure in a legacy system sits.
Cloud migration
Moving infrastructure to cloud-native environments for resilience, easier integration with modern APIs, and elastic capacity. Worth noting that cloud migration alone does not modernize an application; it changes where the same problems run.
Security, compliance, and DevOps modernization
Establishing continuous monitoring, automated audit trails, CI/CD pipelines, and built-in regulatory controls so issues surface early and audits stop being fire drills. Particularly consequential in insurance, healthcare, and government.
Interface and workflow modernization
Updating the interface so the system is accessible, consistent, and usable across devices. This is not cosmetic. Poor usability in a modernized system drives staff back to the spreadsheets and workarounds that created the original problem.
AI-assisted analysis and code transformation
Using AI to analyze large legacy codebases, map dependencies, and accelerate conversion. Genuinely useful for discovery on systems with poor documentation. The judgment about what the system should become still belongs to engineers who understand the business.
Frequently Asked Questions
What is the difference between modernizing a legacy system and rebuilding from scratch?
Modernization preserves the core operational logic and functionality of the existing system while upgrading the infrastructure, database, and code around it, usually in phases with the old and new systems running in parallel. A complete rebuild discards the existing system entirely and starts with a new tech stack and new operational logic. Modernization is generally lower risk and lower cost, because decades of accumulated business rules embedded in the old system are preserved rather than rediscovered.
Why should a business not simply keep its legacy software running?
The main risk is security. Outdated systems use encryption and access control methods that no longer meet modern standards, which creates both breach exposure and compliance failure. Beyond that, unsupported platforms mean no vendor patches, shrinking availability of developers who know the technology, and an inability to integrate with modern tools. The most common failure point is not technical at all: it is the retirement or departure of the one person who understood how the system worked.
Will modernization disrupt day-to-day operations?
It should not, if the work is phased. Ask any prospective partner whether they migrate in stages, whether the legacy system continues running in parallel during the transition, and what the rollback plan is at each stage. Phased delivery also lets you prioritize business-critical components first, so the highest-risk part of the system is addressed earliest.
How long does a legacy modernization project take?
It depends far more on the complexity and documentation quality of the existing system than on its size. A single well-understood application might be modernized in three to six months. A large, poorly documented platform with embedded business rules and multiple integrations is typically a multi-year, phased program. Any firm quoting a timeline before completing a system audit is estimating, not planning.
How much does legacy software modernization cost?
Hourly rates on this list range from roughly $25 to over $400, but rate is a poor predictor of total cost. What drives the number is discovery quality, how much undocumented business logic has to be reverse engineered, and how many integrations are involved. A useful comparison is the annual cost of maintaining the current system, including staff time spent on workarounds and the cost of an outage.
How do I know it is time to modernize?
Common signals: the platform or framework is no longer supported by its vendor, only one or two people understand how the system works, new features take disproportionately long to ship, the system cannot integrate with tools the business now needs, or you are failing or narrowly passing compliance audits. If more than one of these is true, the question is timing rather than whether.
Should we modernize with an internal team or an external partner?
Internal teams have the business context but rarely the capacity, since they are already running the system. External partners bring capacity and migration experience but need time to learn the domain. The practical answer for most established organizations is a partner who takes ownership of the platform long-term, so the institutional knowledge is retained by an organization rather than by an individual who may leave.
Choosing Where to Start
Every firm on this list can modernize software. The more useful question is which of them will still understand your system three years after the project closes.
That question tends to sort the field quickly. Large integrators are built for programs that span an entire enterprise. Offshore delivery firms are built for capacity. Specialist shops are built for particular technologies. Each of those is the right answer for someone. The mismatch happens when an established mid-market company with one critical platform and no internal program office hires a partner built for a different kind of buyer.
If your situation is the common one, a system that has quietly become the thing the business cannot operate without, the criterion that matters most is continuity: who holds the knowledge, and for how long.
ISU Corp has been doing that work for over twenty years, for organizations that measure their partnerships in decades rather than sprints. If your legacy system has become a risk you think about more often than you would like, talk to us about what modernization would actually look like for it.
Company data verified August 2026.
Related reading: Top Custom Software Development Companies for Manufacturing in 2026