The best application modernization companies for 2027 modernize in increments, use AI to speed up code analysis and testing, and keep the business running during the move. Our shortlist: Ortem Technologies (AI-assisted, incremental modernization for mid-market apps), IBM Consulting (generative AI-assisted assessment, refactoring and hybrid cloud), Infosys and Cognizant (large enterprise portfolios), Hexaware (legacy transformation at scale), SCAND (AI legacy modernization for custom systems), Kellton (enterprise app modernization) and Argano (enterprise business applications). AI-assisted teams report 40–60% shorter analysis phases. Hourly rates typically range from about $75 to $180 depending on provider and region.
Application modernization is the process of updating legacy software, such as monoliths, old frameworks and on-premises systems, into maintainable, secure and usually cloud-native systems while preserving the business logic built into them. Approaches range from rehosting and re-platforming to refactoring into services and rebuilding selected modules.
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Get free estimateLegacy systems rarely fail all at once. They slow down every change, make hiring harder, and quietly block AI and cloud projects. That is why searches for custom app modernization firms and legacy modernization services keep growing. This guide compares the best application modernization companies for 2027 and explains how AI is changing the economics of modernization.
Quick comparison: application modernization companies for 2027
| Company | Best for | Approach | Scale |
|---|---|---|---|
| Ortem Technologies | Mid-market custom applications | AI-assisted, incremental modernization with automated tests | Focused teams |
| IBM Consulting | Hybrid cloud enterprise estates | Generative AI-assisted assessment, refactoring, containerization, microservices | Global enterprise |
| Infosys | Large enterprise portfolios | Portfolio-wide modernization programs | Global enterprise |
| Cognizant | Enterprise application estates | Large modernization and cloud programs | Global enterprise |
| Hexaware | Legacy transformation at scale | Automated legacy transformation | Large enterprise |
| SCAND | Custom legacy systems | AI legacy system modernization | Mid-size |
| Kellton | Enterprise app modernization | Assessment to cloud-native rebuild | Mid to large |
| Argano | Enterprise business applications | Modernizing ERP and business app landscapes | Mid to large |
How we built this list
Ortem Technologies wrote this guide and includes itself with that disclosure. We reviewed each provider's published modernization material and 2026 industry roundups (checked October 2026), focusing on incremental approaches, AI-assisted tooling, testing discipline and delivery fit.
How AI changes modernization in 2027
AI is now the engine that makes modernization faster and less risky. Teams use it for four jobs:
- Code comprehension: generating documentation and business-rule summaries for undocumented code.
- Test generation: writing unit and integration tests before anything is refactored.
- Incremental translation: converting older languages and frameworks to modern equivalents module by module.
- Dependency mapping: tracing data flows across systems that manual analysis misses.
Teams using AI-assisted migration report 40–60% shorter analysis phases. Read more in AI-powered application modernization and our AI coding agents legacy Java migration study.
Modernization approaches and costs
| Approach | What it means | Typical effort |
|---|---|---|
| Rehost | Move as-is to cloud infrastructure | Lowest cost, least benefit |
| Re-platform | Move with targeted changes (managed database, containers) | Low to moderate |
| Refactor | Restructure code, often into services, without changing behaviour | Moderate to high |
| Rebuild selected modules | Replace the worst parts with new code, strangler-style | High, but staged |
| Replace | Swap for SaaS where the function is generic | Varies with licence and migration |
Provider rates in 2026 roundups typically range from about $75 to $180 per hour; see our software development cost by country for regional comparisons.
The best application modernization companies for 2027
1. Ortem Technologies: best for mid-market, AI-assisted modernization
Ortem modernizes custom web, mobile and back-office applications in increments: AI-assisted code documentation, test generation first, then module-by-module refactoring or rebuild with the business running throughout. See our application modernization services. Best for: mid-market companies with one or a few critical legacy applications.
2. IBM Consulting: best for hybrid cloud enterprise estates
IBM's modernization offering combines generative AI, code generation, application assessment, refactoring, containerization, microservices and hybrid-cloud modernization. Best for: large enterprises with mainframe or hybrid estates.
3. Infosys: best for large enterprise portfolios
Infosys appears in 2026 roundups of leading legacy modernization companies and runs portfolio-wide programs. Best for: enterprises modernizing many applications at once.
4. Cognizant: best for enterprise application estates
Cognizant runs large modernization and cloud migration programs. Best for: enterprises that want one partner across many applications.
5. Hexaware: best for legacy transformation at scale
Hexaware focuses on legacy transformation for large enterprises and publishes modernization research. Best for: large organizations with significant legacy estates.
6. SCAND: best for custom legacy systems
SCAND is a custom software company that covers AI-assisted legacy system modernization. Best for: mid-size custom systems that need engineering-led modernization.
7. Kellton: best for assessment-to-rebuild programs
Kellton covers legacy application modernization from assessment to cloud-native rebuild. Best for: enterprises that want a structured end-to-end program.
8. Argano: best for enterprise business applications
Argano focuses on modernizing enterprise business application landscapes. Best for: organizations whose legacy pain sits in ERP and business apps.
A phased modernization plan
| Phase | Duration | Output |
|---|---|---|
| Assessment and documentation | 2–6 weeks | System map, business rules, risk register, roadmap |
| Safety net | 2–4 weeks | Automated tests and monitoring around the legacy system |
| First module | 4–8 weeks | One replaced module in production |
| Incremental migration | Ongoing | Module-by-module replacement, retiring legacy code |
| Decommission | Final | Legacy system switched off, data migrated |
Questions to ask a modernization partner
- How will you document business rules that nobody remembers?
- What test coverage will exist before you change anything?
- Which modules move first, and why?
- How do you keep the old and new systems in sync during migration?
- How do you use AI, and how do you check its output?
- What does each phase cost, and what ships at the end of it?
Related reading:
- Microservices vs monolithic architecture
- Custom software vs SaaS
- Best AI integration companies
- How to choose a software development company
Stuck on a legacy system? Book a modernization assessment.
About Ortem Technologies
Ortem Technologies is a premier custom software, mobile app, and AI development company. We serve enterprise and startup clients across the USA, UK, Australia, Canada, and the Middle East. Our cross-industry expertise spans fintech, healthcare, and logistics, enabling us to deliver scalable, secure, and innovative digital solutions worldwide.
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Sources & References
- 1.Top companies providing AI-led application modernization services - Rootstack
- 2.Top 10 Legacy Modernization Companies - Hexaware
- 3.Top 10 Companies for AI Legacy System Modernization - SCAND
- 4.Legacy app modernization guide - Kellton
- 5.What Is Legacy Application Modernization? - Argano
About the Author
Technical Lead, Ortem Technologies
Ravi Jadhav is a Technical Lead at Ortem Technologies with 13+ years of experience leading development teams and managing complex software projects. He brings a deep understanding of software engineering best practices, agile methodologies, and scalable system architecture. Ravi is passionate about building high-performing engineering teams and delivering technology solutions that drive measurable results for clients across industries.
Frequently Asked Questions
- Commonly shortlisted firms include Ortem Technologies, IBM Consulting, Infosys, Cognizant, Hexaware, SCAND, Kellton and Argano. Large firms suit enterprise-wide portfolios; smaller specialists suit mid-market applications that need hands-on engineering and faster delivery.
- It depends on code size, technical debt and the approach. Re-platforming a single application can cost tens of thousands of dollars, while refactoring a large monolith into services can run into hundreds of thousands. Provider rates typically range from about $75 to $180 per hour.
- AI helps with code comprehension and documentation of undocumented systems, automatic test generation before refactoring, incremental code translation from older languages and frameworks, and dependency mapping across systems. Teams using these techniques report substantially shorter analysis phases.
- Incremental modernization is usually safer. Wrapping the legacy system in tests and replacing it module by module, often with the strangler pattern, keeps the business running and delivers value early. Full rewrites carry high risk of delays and lost business rules.
- Assessment typically takes 2–6 weeks. Modernizing a single mid-size application often takes 3–9 months; large enterprise portfolios run for one to several years in phases.
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