A public cloud uses a shared infrastructure managed by a third-party provider and is accessed over the internet, whereas a private cloud uses a dedicated infrastructure that is controlled by a single organization. A hybrid cloud combines both. Choosing the right cloud model comes down to a simple trade-off between how much control your company needs and how much management it's equipped to handle. Public clouds are typically used in organizations that need cost-efficiency, flexibility, and scalability, such as software-as-a-service (SaaS), e-commerce, startups, or gaming platforms. Private clouds are most often used in industries like finance or healthcare, where data must be secure and regulatory standards are strict. Hybrid clouds are used in organizations that need to keep sensitive workloads private but can use public cloud services for scale.
Key takeaways
- A public cloud is always operated and managed by a third-party provider like Amazon Web Services (AWS), Microsoft Azure, or Google Cloud.
- A private cloud hosts one organization only, and it can run in the company’s own data center or be hosted off-site by a third party.
- A hybrid cloud combines public and private cloud resources, giving companies the flexibility to run sensitive operations privately (on-prem or in the cloud) while using public cloud for everything else.
- The three cloud environment models—private, public, and hybrid—are not mutually exclusive; many enterprises run all three simultaneously.
- A fourth model is emerging—hybrid multicloud—that contains one private cloud and more than one public cloud, allowing companies to choose the best public cloud provider for each specific workload.
Table of contents
- Public cloud vs. private cloud vs. hybrid cloud — differences
- Public cloud vs. private cloud vs. hybrid cloud — similarities
- What kind of cloud deployment models are available?
- What is a public cloud?
- What is a private cloud?
- What is a hybrid cloud?
- How hybrid clouds split the work
- How to choose the right cloud model
- How MongoDB Atlas supports any cloud model
- Frequently asked questions
- Related resources
Public cloud vs. private cloud vs. hybrid cloud — differences
The key differences between public, private, and hybrid clouds come down to ownership, control, scalability, and cost structure.
Most organizations don’t operate in just one of these models—they combine them based on workload needs. No single cloud model is universally better.
TECH TIP: Conventional wisdom says that regulated industries always need private ecosystems and everyone else should use public cloud environments. But the decision is not that simple. A regulated industry might need the flexibility of a public cloud for a business application and a non-regulated industry may face data sovereignty requirements that force certain data to stay within specific geographical boundaries, regardless of which cloud model they prefer.
Public cloud vs. private cloud vs. hybrid cloud — similarities
Despite all their differences, all three cloud models share the same core characteristics:
- Same foundation: All three rely on virtualization to deliver compute, storage, and networking as on-demand resources rather than fixed assets.
- Same service models: Public, private, and hybrid clouds all support IaaS, PaaS, and SaaS—the delivery model is independent of the deployment model.
- Same modern app support: Containers, microservices, and automated orchestration work across all three environments.
- Same integration layer: APIs are what makes all three function, and what makes it possible to move workloads between them.
- Same goal: Deliver the right computing resources to the right workload, at the right cost and security level.
What kind of cloud deployment models are available?
Three kinds of cloud deployment models are available—public, private, and hybrid. Which cloud computing model a company chooses depends on their business needs and goals:
- Public clouds are used when speed, cost, and scale are the main objectives.
- Private clouds are used when control, security, and compliance are mandatory.
- Hybrid clouds are used when companies need both options: private clouds for sensitive workloads and public clouds for everything else.
Public clouds, private clouds, and hybrid clouds are not mutually exclusive—many enterprises run on all three. A new cloud computing model—hybrid multicloud—is growing in popularity. It combines a private cloud with more than one public provider, giving enterprises the flexibility to choose the best provider for specific types of workloads.
TECH TIP
Public cloud, private cloud, and hybrid cloud models came about due to advances in virtualization and networking. Virtual machines within public clouds allow a single physical server to run multiple isolated environments, while secure network connections such as virtual private networks (VPNs) make it possible to access and connect to the cloud from anywhere.
What is a public cloud?
A public cloud is an online cloud computing environment where the infrastructure is operated and managed by third-party cloud service providers like Amazon Web Services (AWS), Microsoft Azure, or Google Cloud Platform. Organizations choose public clouds when they need to scale resources on demand—only needing to pay for what they use.
A public cloud can run the workloads of many different companies on the same server, but each company remains unaware of the others because they are separated by server partitioning. Also known as virtualization, server partitioning divides a physical server into multiple, independent virtual machines, allowing each company to function as its own entity.
Example: A public cloud model is similar to multiple apartments in one building: each unit is isolated, but the electricity and plumbing infrastructure is shared by all. Likewise, third-party cloud providers offer computing power to thousands of companies simultaneously via virtualization, but the underlying hardware is shared.
A public cloud is best for:
- Startups and software-as-a-service (SaaS) companies that need to scale fast as demand changes.
- Development environments that need increased capacity during temporary testing windows.
- Organizations that don’t have regulatory or data sensitivity constraints.
- Workloads where cost efficiency and speed matter more than control.
- Companies that need access to artificial intelligence (AI) tools, GPU infrastructure, or machine learning platforms that are only available at scale from public cloud providers.
Public cloud environments offer less direct control over infrastructure, which may not meet the needs of some organizations with strict requirements or highly sensitive data.
What is a private cloud?
Unlike public clouds, a private cloud’s infrastructure is dedicated to a single organization. It can be hosted in an company’s own on-premises data center or managed by a third-party provider on dedicated hardware. The defining characteristic of a private cloud is exclusivity—one organization lives in one model. This isolation is why it’s often the preferred option for financial institutions, government agencies, and heavily regulated industries.
A private cloud is best for:
- Organizations that need full control over their security posture.
- Workloads involving sensitive or confidential data that cannot live on a shared infrastructure.
- Companies that have dedicated IT resources to manage and maintain a standalone infrastructure.
The isolated infrastructure of private clouds gives organizations full control over how their system is configured and secured. Their IT teams set access permissions, manage encryption standards, and control how data is organized and stored. They typically use secure internal networks, along with technologies such as VPNs and firewalls to restrict access.
The tradeoff of the private cloud model is the cost and complexity. Private clouds often require significant upfront investment in hardware and ongoing operational management. Scaling capacity is often slower, especially in on-premises environments, because the physical infrastructure must be ordered, configured, set up, and managed.
TECH TIP
Why is it called a private “cloud” if the hardware is on-premises? The word “cloud” in all deployment models—private, public, and hybrid—refers to how the resources are delivered, not where the hardware sits. The “cloud” is where a company’s resources are available on demand through software. It can be hosted by a public cloud service provider, a private cloud service provider, or the company itself.
What is a hybrid cloud?
A hybrid cloud combines the flexibility of a public cloud with the security of a private cloud. Hybrid clouds are helpful when a company has both sensitive data or workflows and non-sensitive data or workflows.
For example, in a compliance-focused company like financial services, the private cloud is likely set up as the primary model. But when a temporary spike occurs, like a special credit card promotion, the public cloud kicks in to handle the short-term increase in demand on the server. This type of scalability is achieved through application programming interfaces (APIs) and VPNs that sit on the integration layer between the public and private cloud. APIs allow applications to move workloads or share data between private and public cloud systems. Secure network connections, such as VPNs, keep data protected as it travels between the private and public infrastructures.
TECH TIP
When two systems are connected, the public cloud handles short-term demand spikes through a technique known as cloud bursting. Cloud bursting allows the sensitive data to stay on the private cloud while non-sensitive computing workloads in the private cloud can “burst” to the public cloud when more capacity is needed.
How hybrid clouds split the work
Workloads are routed to the environment best-suited for them.
How to choose the right cloud model
Choosing the right cloud model depends on a company’s data sensitivity, workload requirements, scalability needs, and internal resources. Other considerations include:
- Data sovereignty: Some countries and industries have laws that dictate how data must legally be managed and stored, which can force a company to make an infrastructure decision that’s not based on cost or performance.
- Budget: Public clouds reduce upfront costs but can introduce ongoing usage expenses. Private clouds require a higher initial investment but offer predictable control over infrastructure.
- Internal expertise: Managing a private cloud requires dedicated IT resources, while public cloud shifts much of that responsibility to the provider.
- Scalability: Organizations with unpredictable demand often benefit from public or hybrid deployments, while stable workloads may fit well in private environments.
Companies are not restricted to one cloud computing model
Public, private, and hybrid cloud models define where your infrastructure runs, who controls it, and how it scales. But the real advantage isn’t choosing one, it’s the freedom to use all three strategically. Organizations that match the right system to the right workload or environment, gain simultaneous control over cost, performance, security, and compliance, giving them the flexibility to scale easily as requirements change.
How MongoDB Atlas supports any cloud model
MongoDB Atlas is designed to work across cloud environments, so your cloud strategy and data strategy isn’t tied to a single infrastructure choice.
MongoDB Atlas runs natively on major cloud providers, including AWS, Azure, and Google Cloud Platform, allowing organizations to deploy applications where it makes the most sense without being locked into one provider. It also supports hybrid and multicloud architectures. Organizations can keep sensitive workloads in controlled network environments while using public cloud infrastructure for scale and performance.
For private and hybrid use cases, MongoDB Atlas supports secure connectivity through private endpoints.
Get started with a free MongoDB Atlas cluster—no credit card required.