Top cloud service providers for modernizing IT: AWS, Azure and Google Cloud compared
The leading cloud service providers for modernizing IT infrastructure are AWS, Microsoft Azure and Google Cloud, which together held 63% of worldwide cloud infrastructure services in Q4 2025. Pick the one that fits your estate: Azure for Microsoft-heavy shops, AWS for service breadth, Google Cloud for data and analytics. Then choose a partner to run the migration.
Key takeaways
- Synergy Research Group put Amazon at 28%, Microsoft at 21% and Google at 14% of worldwide cloud infrastructure services in Q4 2025.
- All three run migration programmes and now offer AI-assisted modernization tools: AWS Transform, the Azure Copilot migration agent on Azure Migrate, and Google Cloud's Migration Center and modernization tools.
- Modernization is more than moving servers. Decide per application between retire, retain, rehost, relocate, repurchase, replatform and refactor.
- Oracle, IBM and Alibaba Cloud are worth a look for specific workloads, such as Oracle databases, mainframe-adjacent estates or China and APAC reach.
- The platform rarely decides success on its own. Partner skills, a tested migration plan and operations after go-live matter as much.
What does IT infrastructure modernization involve?
It means moving workloads off ageing hardware and licences onto cloud services, and changing how they are built and run where that pays off. Most programmes mix several approaches across the application portfolio.
AWS describes seven migration strategies, the 7 Rs. The same vocabulary works on any cloud.
| Strategy | What it means | Typical use |
|---|---|---|
| Retire | Switch the application off | Duplicate or unused systems found in discovery |
| Retain | Keep it where it is for now | Systems with hard latency, licence or end-of-life constraints |
| Rehost | Move virtual machines as they are | Fast data centre exits and VMware estates |
| Relocate | Move a whole platform, such as VMware, to a cloud-hosted version | Large virtualised estates that need to move quickly |
| Repurchase | Replace with SaaS | Email, CRM, HR and other commodity systems |
| Replatform | Swap parts for managed services, such as a managed database | Reducing operations work without rewriting code |
| Refactor | Re-architect to containers, serverless or microservices | Core products where scale and release speed matter |
Which cloud providers lead for modernization?
The three hyperscalers lead on scale and tooling. According to Synergy Research Group, quarterly cloud infrastructure revenues reached $119.1 billion in Q4 2025, and Microsoft and Google are growing faster than Amazon.
Amazon Web Services (AWS)
AWS has the broadest service catalogue and the most mature migration programme. The AWS Migration Acceleration Program (MAP) uses a three-phase method (assess, mobilize, migrate and modernize) delivered with partners. For modernization, AWS Transform uses agentic AI to automate migration of VMware, bare-metal and hybrid workloads and to modernize mainframe, Windows and custom code. AWS suits organisations that want the widest choice of building blocks and a large partner ecosystem.
Microsoft Azure
Azure is the natural choice when the estate already runs on Windows Server, SQL Server, Active Directory and Microsoft 365. Existing licences can lower the cost of moving, and identity integrates directly. Azure Migrate handles discovery and assessment, including VMware environments, and Microsoft now offers an Azure Copilot migration agent built on it. For workloads that must stay on-premises, Azure Arc and Azure Local extend Azure management into your own data centre.
Google Cloud
Google Cloud is strongest in data, analytics and AI, with BigQuery and Kubernetes (GKE) at the centre. Its Migration Center covers assessment and planning, with tools such as Migrate to Virtual Machines, Migrate to Containers, a Mainframe Assessment Tool and Dual Run for mainframe modernization. Operations use Cloud Monitoring and Cloud Logging. Enterprise buyers can add Premium Support, which offers a 15-minute initial response for P1 cases around the clock.
Other providers worth a look
- Oracle Cloud Infrastructure: worth considering for estates built on Oracle Database and Oracle applications.
- IBM Cloud: fits organisations with IBM Power, mainframe or Red Hat OpenShift investments.
- Alibaba Cloud: Alibaba Group runs its own e-commerce platforms, including AliExpress, on it. Relevant for China and parts of APAC.
- European and sovereign clouds: some public sector and regulated buyers in the EU shortlist regional providers for data sovereignty reasons, often alongside a hyperscaler.
How do AWS, Azure and Google Cloud compare?
| AWS | Microsoft Azure | Google Cloud | |
|---|---|---|---|
| Q4 2025 share (Synergy) | 28% | 21% | 14% |
| Migration programme and tools | MAP, AWS Transform | Azure Migrate, Azure Copilot migration agent | Migration Center, Migrate to Virtual Machines, Migrate to Containers |
| Hybrid and on-premises | AWS Outposts | Azure Arc, Azure Local | Google Distributed Cloud |
| Strongest fit | Broad service choice, large partner ecosystem | Microsoft-centric estates and licences | Data, analytics, AI and Kubernetes |
| Watch out for | Many overlapping services; design discipline needed | Licence terms and identity design need care | Smaller partner pool in some countries |
For a deeper side-by-side on services and pricing, see our AWS vs Azure vs Google Cloud comparison.
Which companies offer AI-driven cloud modernization?
All three hyperscalers now sell AI-assisted modernization tooling, and most large partners build their own accelerators on top. The tools help most with discovery, dependency mapping, code conversion and test generation.
They do not remove the need for engineering judgement. Converted code still needs functional testing, performance testing and a rollback plan. Treat AI tooling as a way to shorten the assessment and conversion phases, not as a substitute for a migration plan.
Do you need a modernization partner?
Most organisations do, at least for planning and the first migration waves. The cloud provider supplies the platform; a partner supplies the people who design landing zones, move workloads, and run them after go-live.
When choosing a partner, check:
- Platform validation: for example AWS Migration and Modernization Competency, Azure specialisations, or Google Cloud partner specialisations, confirmed in each provider's directory.
- Funding access: whether the partner can run your project under programmes such as AWS MAP.
- Hybrid skills: who will run the servers you retain on-premises, including hardware refreshes on Dell, HPE or other platforms.
- Operations after migration: a partner that also runs the estate has a direct reason to build it well. See our guide to managed cloud services.
How to choose a cloud provider for modernization
- Start from your estate. Count Windows and SQL Server licences, Oracle databases, VMware hosts and mainframe workloads. They often decide the platform.
- Follow your data. Analytics-heavy organisations should test where their data platform runs best before moving applications.
- Check regions and sovereignty. Confirm the regions you need, and how the provider handles EU data residency or Indian data protection requirements.
- Compare support plans. Response targets and access to named technical contacts differ by plan and price.
- Model costs over three years. Include commitments, licences, egress and the cost of running both environments during migration. Our cloud cost optimization team can help build the model.
- Plan the exit. Use infrastructure-as-code and open formats so a later move stays possible.
How Opsio helps
Opsio plans and runs AWS migrations as an AWS Advanced Tier Services Partner, and also works with Azure and Google Cloud.
For WorkBuster, a SaaS recruitment platform used around the world, Opsio migrated a MySQL database from a VMware hypervisor to AWS with a near-zero downtime approach. The new platform runs on multi-AZ MySQL RDS behind an Application Load Balancer with auto-scaling, is deployed with AWS CloudFormation as infrastructure-as-code, and follows the AWS Well-Architected Framework, with encryption in transit and at rest.
Frequently asked questions
Which cloud service provider is best for modernizing IT infrastructure?
There is no single best. AWS offers the widest service choice, Azure suits Microsoft-centric estates, and Google Cloud is strongest for data and analytics. Your licences, data and skills usually decide.
What are the best infrastructure as a service providers?
AWS, Microsoft Azure and Google Cloud are the largest IaaS providers by market share. Oracle Cloud Infrastructure, IBM Cloud and Alibaba Cloud are relevant for specific workloads and regions.
Which companies offer AI-driven cloud modernization platforms?
AWS offers AWS Transform, Microsoft offers an Azure Copilot migration agent built on Azure Migrate, and Google Cloud offers Migration Center with tools for virtual machines, containers and mainframes. Many partners add their own accelerators.
What is the difference between a cloud provider and a modernization partner?
The cloud provider runs the platform and data centres. A partner assesses your applications, designs the target setup, migrates workloads and often operates them afterwards.
How long does an infrastructure modernization take?
It depends on the number of applications, their dependencies and the strategies chosen. Most programmes run in waves: assess first, migrate simple workloads early, and refactor core systems over a longer period.
For hands-on delivery, see service provider in cloud computing.
Related reading
About the Author
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