Choosing between AWS and Microsoft Azure should rarely start with the question: “Which cloud has more services?” For a CTO, what matters more is which platform is a better fit for a specific workload, the existing architecture, team capabilities and cost model — and how much it may cost to reverse that decision in a few years.
A poor choice does not necessarily lead to an outage. More often, it results in higher TCO, harder integrations, additional capability costs, greater vendor lock-in or a future migration whose cost exceeds the expected savings.
AWS or Azure — which should you choose? Azure is a natural candidate for organizations with a strong Microsoft ecosystem, significant Windows Server or SQL Server workloads and licences that affect TCO. AWS is particularly worth considering when the company already has a substantial AWS estate, established team expertise and architecture built around AWS-native services. In other cases, the decision is best made for a specific workload using five criteria: architecture fit, risk, people, economics and exit.
AWS vs Azure — key differences
AWS and Microsoft Azure are mature cloud platforms offering compute, storage, databases, containers, serverless, analytics, AI, security and operational tooling. From a CTO’s perspective, the key difference is therefore not the number of available services, but how well the platform fits the existing environment and a specific workload.
A real advantage appears when one platform integrates better with the current stack, allows the organization to reuse existing skills, lowers licensing and operating costs or simplifies the target architecture.
Key principle: do not compare AWS and Azure in the abstract. Compare two concrete architectures designed to meet the same business and technical requirements.
How to choose between AWS and Azure: a framework for CTOs
It is worth evaluating the decision across five layers. This prevents cloud selection from being reduced to pricing or a checklist of individual services.
| Layer | What to assess | Risk if ignored |
|---|---|---|
| Architecture fit | Workload, data, integrations, performance, availability, DR. | A more expensive or more complex architecture. |
| Risk | Security, compliance, data residency, RPO/RTO. | Regulatory and operational risk. |
| People | Team skills, CloudOps, DevOps, support. | Higher hiring costs and slower delivery. |
| Economics | Cloud bill, licensing, operations, migration and TCO. | Local savings at the expense of the overall system. |
| Exit | Vendor lock-in, portability, switching cost. | An expensive provider change in the future. |
When should you choose AWS and when Azure?
| Situation | What supports the choice? |
|---|---|
| Strong Microsoft ecosystem | Azure is a natural candidate with Windows Server, SQL Server, Microsoft Entra ID and licences that affect TCO. |
| Existing AWS estate | AWS allows the organization to reuse existing architecture, skills, governance and operating processes. |
| Greenfield | No default winner — compare architecture, TCO, skills and exit cost. |
| Specific native capability | A provider may have an advantage if a specific capability materially simplifies the solution or reduces delivery cost. |
In Microsoft-heavy environments, Azure Hybrid Benefit may also affect the economics for eligible Windows Server and SQL Server licences. This does not mean every Windows or .NET workload should automatically move to Azure.
Likewise, an existing AWS estate should not prevent change. A migration should, however, have a measurable business case that also covers switching cost.
AWS vs Azure — comparison of key services
| Need | AWS | Azure |
|---|---|---|
| Compute | Amazon EC2 | Azure Virtual Machines |
| Object storage | Amazon S3 | Azure Blob Storage |
| Relational database | Amazon RDS / Aurora | Azure SQL / managed databases |
| Serverless | AWS Lambda | Azure Functions |
| Kubernetes | Amazon EKS | Azure Kubernetes Service |
| Identity | AWS IAM / IAM Identity Center | Microsoft Entra ID / Azure RBAC |
| AI / GenAI | Amazon Bedrock / SageMaker AI | Microsoft Foundry |
Service mapping is useful for orientation, not for selecting a provider. Services in the same category may differ in pricing, SLA, limitations, integrations and operational model.
AWS or Azure — which cloud is cheaper?
Without defining the workload, it is not possible to reliably identify the cheaper provider. Compute pricing is only one part of the total cost.
TCO = cloud consumption + licensing + operations + people + governance + security + migration + dependency cost
A meaningful comparison should include compute, storage, networking, data transfer, managed services, observability, backup, disaster recovery, support, licensing and team effort.
FinOps should therefore be considered before migration, not only after the first unexpectedly high cloud invoices. Usage patterns, commitments, egress, non-production environments and cost allocation can materially change the outcome of the comparison.
The cloud bill is not the same as TCO. An architecture that looks cheaper at the infrastructure level may cost more over three to five years if it requires more operations, specialist skills or creates expensive dependencies.
AWS vs Azure — security, compliance and data residency
There is no sound basis for treating AWS or Azure as “secure by definition” compared with the other. Both providers offer extensive security capabilities and operate under a shared responsibility model.
The actual security posture depends primarily on architecture and configuration: IAM, least privilege, encryption, secrets management, network segmentation, logging, monitoring, backup and disaster recovery.
The biggest source of risk is often not the provider, but how the environment is designed and operated.
European enterprises should also assess data residency and the regulatory requirements applicable to the organization, such as GDPR, NIS2 or — where relevant — DORA. Provider certifications do not replace sound architecture, configuration and governance on the customer side.
Vendor lock-in, hybrid and multi-cloud — where does the complexity cost appear?
Vendor lock-in is not binary. Managed services may increase dependency on a provider, but they can also reduce custom code, accelerate delivery and lower operational effort.
Instead of trying to eliminate lock-in entirely, define what level of provider dependency the organization is willing to accept in exchange for lower development cost, simpler operations and faster time-to-market.
When does multi-cloud make sense?
Multi-cloud may result from M&A, different business units, regulatory requirements, an existing cloud estate or workload-specific needs. It should not, however, be treated as the default way to reduce lock-in.
A second provider means additional IAM, networking, monitoring, security, FinOps, governance, tooling and skills. Multi-cloud reduces some dependencies, but it also increases the cost of complexity.
When is hybrid cloud justified?
Hybrid cloud can be a migration stage or a deliberate target state due to legacy systems, latency, data gravity, local integrations or compliance. The business and architectural problem should be defined first, and the technology selected afterwards.
Is it worth migrating from AWS to Azure or from Azure to AWS?
Migration between providers makes sense when the value of the future state exceeds the full switching cost. The business case may come from environment consolidation, a change in technology strategy, licensing that materially affects TCO or a specific limitation of the current platform.
Switching cost should include:
engineering + data transfer + replatforming/refactoring + testing + parallel run + downtime risk + retraining + governance + changes to operating processes.
Moving to the cloud does not automatically mean becoming cloud-native. Rehosting VMs can be a rational migration step, but it does not guarantee lower TCO or greater resilience. Provider selection should therefore be separated from the migration strategy: rehost, replatform or refactor.
What does this look like in practice?
In environments combining cloud and on-premise infrastructure, the decision does not end with provider selection. Business continuity, monitoring, backup, disaster recovery and hybrid operations also need to be considered. See how Edge One Solutions supported Respect Energy in developing and securing an Azure and hybrid infrastructure environment →
AWS vs Azure — decision matrix for CTOs
| Scenario | Starting point | What decides? |
|---|---|---|
| Microsoft-heavy enterprise | Azure as a natural candidate | Licensing, Entra ID, Windows/SQL, integrations |
| Greenfield SaaS | AWS and Azure | Skills, architecture fit, managed services, TCO |
| Legacy Windows | Azure as a natural candidate for analysis | Licensing, dependencies, migration strategy |
| Existing AWS estate | AWS | Does the value of change cover the switching cost? |
| Existing Azure estate | Azure | Does the value of change cover the switching cost? |
| AI / GenAI | Both platforms | Data, models, integrations, governance, inference cost |
| Cost-sensitive workload | No default winner | Workload-specific TCO over three to five years |
What about Google Cloud? GCP is worth adding to the shortlist when an existing Google Cloud estate or specific data, analytics or AI requirements create a real business case. A third provider should not be analysed simply for completeness.
10 questions to ask before choosing AWS or Azure
- What exact workload are we evaluating?
- Which systems does it need to integrate with?
- Where is the data located and where may it be processed?
- What are the availability, RPO, RTO and latency requirements?
- What cloud skills does the team already have?
- How do existing licences and contracts affect TCO?
- What will the environment cost over three to five years?
- What will migration and parallel run cost?
- What level of vendor lock-in are we willing to accept?
- What is the exit plan if the business case changes?
If the organization cannot answer several of these questions, provider selection is probably premature. Requirements, architecture and the business case should be clarified first.
FAQ – AWS vs Azure
Summary: AWS or Azure? Start with the workload, not the ranking
AWS and Azure are mature enough that both can meet the core technical requirements in many scenarios. The meaningful differences appear only after considering the existing stack, data, integrations, team skills, security, licensing and the cost of future change.
That is why the decision should be evaluated through five filters: architecture fit, risk, people, economics and exit. This helps avoid choosing a provider based only on VM pricing, the number of available services or market popularity.
The most important question is not: “Which cloud is better?” For a CTO, the better question is: “Which architecture meets the requirements of this workload at an acceptable TCO, risk level and cost of future change?”
CLOUD × ARCHITECTURE × DELIVERY
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