Top application modernization companies and how to choose one

Application modernization companies by type

Global system integrators

Accenture, IBM Consulting, Capgemini and Cognizant run modernization programmes across thousands of applications. IBM Consulting is a natural candidate when mainframes (IBM Z) and Red Hat OpenShift are in scope. Capgemini has a large European footprint. These firms make sense when you need one accountable supplier for a multi-year, multi-country programme.

India-based IT services firms

Tata Consultancy Services (TCS), Infosys, Wipro and HCLTech combine onshore architects with large delivery centres in India. They are strong at code conversion, testing at scale and long-running application management. For Indian buyers they also offer local contracts and support in the same time zone.

Nordic IT services providers

CGI (headquartered in Canada, with large operations in Sweden and Finland) and Tietoevry (Finnish-Norwegian) are common choices for Nordic public sector, banking and industrial companies that want local delivery teams and contracts under local law.

Engineering specialists

Thoughtworks and EPAM are known for software engineering practice: breaking monoliths into services, continuous delivery and building in-house product teams. They fit when the hard part is the code and the domain model, not the infrastructure.

Cloud-focused managed service providers

AWS and Azure partners modernize the platform and then operate it. You can check AWS partner status, including the Migration and Modernization Competency, on the AWS Competency Program pages. Opsio belongs here: an AWS Advanced Tier partner with the AWS Migration Competency, offices in Karlstad (Sweden) and Bangalore (India), and a focus on mid-market companies that want migration, application modernization and 24/7 operations from one team.

What does application modernization actually involve?

It means changing how an application is hosted, built or designed so it is cheaper to run, safer and faster to change. In practice each application gets one of the "7 Rs".

AWS Prescriptive Guidance lists seven migration strategies: retire, retain, rehost, relocate, repurchase, replatform and refactor (or re-architect).

The same AWS guidance says refactoring is not recommended for large migrations, because it is the most complex strategy. It suggests rehosting, relocating or replatforming first and modernizing after the move. A partner that proposes refactoring everything up front should explain why. Our explainers on replatforming and legacy application modernization go deeper into each option.

For refactoring, the strangler fig pattern is the common low-risk route. AWS describes it as gradually extracting features from a monolith into new services until the old system can be retired, instead of a big-bang rewrite.

Tools and platform programmes to ask about

Partners increasingly use AI-assisted tools for code analysis, dependency mapping and conversion. Ask which tools they use and what still needs manual work.

• AWS Transform: AWS's agent-based service for migration and modernization work such as .NET, mainframe and VMware transformations. See the AWS Transform user guide.
• AWS Mainframe Modernization: its documentation now states that the managed runtime and self-managed experiences are no longer open to new customers. Existing customers can continue. A bid built on it for a new customer is a red flag.
• Microsoft Cloud Adoption Framework: Microsoft's modernize guidance is the Azure equivalent for planning and governing modernization.
• Containers and IaC: Kubernetes (Amazon EKS, AKS), Terraform or CloudFormation, and CI/CD pipelines are standard. Ask to see example pipelines and IaC repositories from past work.

How to choose an application modernization partner

Choose on evidence from comparable work, not on slides. A short paid assessment of three to five applications is the best test of a partner before a large commitment.

Selection checklist

• Comparable references. Same technology stack, similar size, same target cloud. Call the reference customers.
• Verifiable credentials. AWS or Microsoft partner tier and competencies that you can look up yourself.
• Assessment method. How they inventory apps, map dependencies and assign one of the 7 Rs per application.
• Named delivery team. The architects and leads in the proposal should be the people who do the work.
• Security and compliance. GDPR, NIS2 or sector rules for Nordic and EU buyers; the DPDP Act for Indian buyers. Ask where data and support staff are located.
• Testing and cutover. Parallel runs, blue-green or canary releases, rollback plans and data validation.
• Day-2 operations. Who monitors, patches and pays attention to cost after go-live, and on what SLA.
• Commercial model. Fixed price per wave, time and materials, or outcome-based. Ask what triggers change requests.

Questions to put in your RFP

1. Which strategy would you choose for each of our top ten applications, and what would change your mind?
2. What is your typical sequence of waves, and what do you modernize after migration?
3. Show one modernization you delivered that went wrong. What did you change?
4. Which tools do you use for discovery, code analysis and testing, and are any of them end-of-sale?
5. How do you hand over knowledge to our team, or run the system for us afterwards?

What drives the cost of modernization?

Cost depends far more on the application mix than on the supplier's day rate. Published price lists are rare, so build your comparison from the drivers below.

• Number of applications and the share that need refactoring rather than rehosting or replatforming.
• Code age and language: COBOL and heavily customised ERP cost more to change than modern Java or .NET.
• Test coverage: little automated testing means more manual regression work.
• Data volume and migration windows.
• Compliance requirements and audit evidence.
• Run costs after go-live, including licences, cloud spend and support.

How Opsio helps

Opsio plans and delivers modernization on AWS and Azure, from AWS migration and replatforming to containers and infrastructure as code, and then runs the result as a managed service.

For Branäsgruppen, one of Sweden's largest ski resort groups, Opsio replatformed a VMware-based on-premises estate onto AWS-managed services with auto-scaling and multi-AZ deployment. The case reports a 40% improvement in average page responsiveness, a 40% reduction in total cost of ownership and application uptime of 99.9%+.

Frequently asked questions

Which companies are best for application modernization?

There is no single best company. Global integrators such as Accenture, IBM Consulting and Capgemini suit very large programmes. TCS, Infosys, Wipro and HCLTech suit high-volume code work. CGI and Tietoevry suit Nordic buyers who want local teams. Cloud MSPs suit mid-market firms that want migration and operations together.

What is the difference between migration and modernization?

Migration moves an application to a new environment, often with little change. Modernization changes how it is hosted, built or designed, for example replacing self-managed databases with managed services or splitting a monolith into services.

How long does an application modernization project take?

It depends on the number of applications and the strategy chosen. Rehosting a few applications can take weeks, while refactoring a core system is usually a multi-month or multi-year programme delivered in waves.

Should we refactor during migration or after?

For large estates AWS recommends migrating first (rehost, relocate or replatform) and modernizing afterwards, because refactoring during migration is the most complex option. Small, high-value applications can be refactored directly if the business case is clear.

Can a smaller provider handle a large modernization?

Yes for a well-defined scope, especially platform and cloud work. For very large code rewrites, many companies combine a cloud MSP for the platform and operations with a development partner for the code.