What is Cloud Computing?
The most cited and accepted definition of cloud computing was developed by the United States National Institute of Standards and Technology (NIST) in its Special Publication SP 800-145, published in September 2011:
“Cloud computing is a model for enabling ubiquitous, convenient, and on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction.”
The NIST definition aims to provide a baseline for discussion about what cloud computing is and how it can be used, outlining its essential characteristics, service models, and deployment models. Its relevance remains: the global cloud infrastructure market has reached 119 billion dollars in revenue in the fourth quarter of 2025 alone, with a year-on-year growth of 301%.
Edge Computing
Unlike traditional cloud computing, the edge computing Edge computing processes data as close as possible to where it is generated, reducing latency and bandwidth consumption. Because edge computing is still evolving, its conceptual boundaries continue to be defined. The Linux Foundation began building the Open Glossary of Edge Computing, which includes the most commonly used definition of the sector:
“The delivery of computing capabilities to the logical edges of a network to improve the performance, operating cost, and reliability of applications and services. By shortening the distance between devices and the cloud resources that serve them, and also reducing network hops, edge computing mitigates the latency and bandwidth constraints of today's internet, ushering in new classes of applications.”
In practical terms, edge computing distributes new resources and software stacks along the path between centralized data centers and the growing number of devices in the field, concentrated very close to the last-mile network.
The IT Stack
To understand how cloud computing works, it is essential to know the information technology stack (IT Stack)The set of layers that make up any modern computer system. Each layer performs a specific function, and all are necessary to generate value for the end user.
Within a modern IT stack, these different layers can reside in multiple physical locations and be operated by different providers simultaneously.
Essential Features of Cloud Computing
NIST defines five essential characteristics that distinguish cloud computing from other computing models:
-
Available via the network: Cloud capabilities are available over the network to a wide range of devices: mobile phones, tablets, and workstations. It's an often underestimated but essential feature.
-
Rapid elasticity: Capacities can scale outward and inward elastically according to demand, giving the customer a sense of virtually unlimited capacity. Elasticity requires the pooling of resources.
-
Resource Pooling: Computing resources are pooled to serve multiple clients in one model multi-tenant. Virtual and physical resources are dynamically allocated according to demand, creating location independence for the customer.
-
Metered service: Cloud systems use measurement capabilities to provide usage reports and transparency to both the user and the provider. Consumption-based billing acts as a financial incentive for users to release unused resources.
-
Self-service on demand: The consumer can provision the necessary capabilities without human interaction with the provider, either through a web user interface (UI) or an application programming interface (API).
Service Models
The three cloud service models define how many layers of the IT stack are managed by the provider and how many are managed by the customer.
Infrastructure as a Service (IaaS)
The Infrastructure as a Service (IaaS) allows the customer to rent basic IT infrastructure—storage, network, operating system, and compute (virtual or dedicated hardware)—on a pay-as-you-go basis. The customer deploys and runs their own software on the provided infrastructure and has control over the selected OS, storage, and network components. In this model, the provider manages from the layer of Facility until Virtualization.
Platform as a Service (PaaS)
The Platform as a Service (PaaS) provides the customer with an on-demand environment to develop, test, and manage software applications, without the need to configure the underlying infrastructure. The provider operates up to the layer of Runtime of the IT stack, while the client manages the upper layers: data and application.
Software as a Service (SaaS)
Software as a Service Software as a Service (SaaS) allows access to software applications over the internet, fully managed by the cloud provider. The provider is responsible for the application's configuration, administration, and updates, including all supporting infrastructure. The customer accesses the application via a web browser or thin client application and controls only a limited set of application-specific configuration options. In this model, the provider manages all the layers of the IT stack.
Implementation Models
Public Cloud
The public cloud is owned and operated by a cloud service provider. All hardware, software, and infrastructure are owned and managed by the provider and operate from its data centers. Resources are available to anyone on a pay-as-you-go or free-to-use basis. Major public cloud providers include AWS, Microsoft Azure, Google Cloud y Salesforce.com. In the fourth quarter of 2025, AWS led the market with a 28% share, followed by Azure with 21% and Google Cloud with 14%.
Private Cloud
A private cloud refers to cloud resources provisioned exclusively for a single company or organization. It can be operated by the organization itself, by a third party, or a combination of both, and can be located in the customer's data center.on-premises) or in a third-party data center.
Hybrid Cloud
Hybrid cloud combines public and private cloud deployments using technology that allows infrastructure and applications to be shared between them. The most common use case is extending on-premises infrastructure to the cloud to support growth. The global hybrid cloud market is projected to be between 158 and 173 billion dollars by 2025, with projections to reach 430 billion in 2030. According to a 2025 Flexera report, the 73% of the organizations It already uses a hybrid cloud model.
Most businesses today operate some form of hybrid cloud, combining public SaaS applications such as Salesforce, Microsoft 365, and Google Workspace with public or private IaaS deployments for their other business applications.
Multi-Cloud
As more cloud providers entered the market with the same service model, businesses began deploying their workloads across different providers' offerings. A company might have workloads running on AWS and Google Cloud simultaneously to ensure the best solution for each use case. Organizations also adopt a multi-cloud approach to continuously evaluate providers in the market or to distribute workload risk.
According to a 2024 Gartner report, more than 92% of the large companies It currently operates in a multi-cloud environment. Meanwhile, 811% of the organizations surveyed in another study reported using two or more cloud providers for greater scalability, security, and flexibility.
Multi-cloud, therefore, is the deployment of workloads across different cloud providers within the same service model (IaaS / PaaS / SaaS).
Cloud Market Context in 2026
Cloud computing continues to grow at an accelerated pace. Here are some key facts about the current landscape:
-
The global cloud infrastructure market reached $119 billion in Q4 2025, one more 30% than the previous year.
-
Cloud services from GenAI grew to 160% in 2025, driving the overall expansion of the sector.
-
Projected annual revenue for cloud providers in 2025 exceed $400 billion for the first time in history.
-
It is estimated that the 90% of the organizations will adopt a hybrid cloud model before 2027.
Primary sources: NIST SP 800-145 (Definition of Cloud Computing), Linux Foundation Open Glossary of Edge Computing v2.0, Synergy Research Group (Q4 2025 market share data), Flexera State of the Cloud Report 2025, Gartner (2024 multi-cloud statistics).