Spencer Nguyen - April 16, 2024

When comparing the types of APIs (application programming interfaces), API architecture types and different API categories are incredibly important. The following article will discuss API architecture and protocol types (REST and SOAP) and three types of API categories (open, internal, and partner).

Here’s the key things to know about the types of APIs your organization might need:

  • REST APIs are lightweight, scalable web APIs that use “Representational State Transfer” to provide data in a standardized form that clients can easily understand, such as returning links to videos when requested.
  • These APIs are stateless, supporting JSON and XML formats, documenting each request, offering a uniform interface for ease of use, and providing detailed error codes to developers for troubleshooting.
  • Compared to SOAP APIs, which are known for heightened security and ACID compliance, REST APIs are generally simpler and more flexible, making them well-suited for web services that require frequent interaction.
  • Open APIs, or public APIs like Google Maps, are accessible to anyone and can enhance transparency, community building, and brand awareness without cost, benefiting from widespread usage and development.
  • Private APIs are restricted for internal use within an organization, ensuring data security by limiting access through API keys, but they can complicate data sharing outside the organization.

Table of Contents

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Rest APIs (also known as RESTful APIs) appeal to many developers and organizations because of their lightweight, scalable designs. REST, by the way, stands for “Representational State Transfer,” which means that when a client uses the API to request information, the server returns information in a standardized representation. That might sound a bit complex to anyone without a lot of API experience. Just know that the client gets information in a way that the user can understand. For example, if you request information about videos, you might get a list of links to videos.

REST APIs are commonly web APIs that cooperate easily with HTML, the markup language used to structure and link websites. When someone using the internet or World Wide Web wants to search for something on your website or database on your server, they request the information. That request gets submitted to appropriate API endpoints that can communicate with the server and send back the requested information. REST is considered one of the most important API architectural styles.

Features of REST APIs

REST API is one of the most popular types of APIs. Some critical features that make them attractive include:

  • They are stateless, which means they complete one request at a time.
  • They support JSON (Javascript Object Notation) and XML format.
  • They document every request.
  • They have a uniform interface that makes them easier to use.
  • They send software developers error code when something goes wrong. (Users get generic errors, such as 404 when a page doesn’t exist. Developers get more meaningful error messages that contribute to solving problems.)


SOAP is an initialism for “simple object access protocol.” SOAP APIs have diverse uses that benefit web services and networks. Modern SOAP APIs transfer information via HTTP protocol (Hypertext Transfer Protocol), so it’s not surprising that many websites rely on it for client-server communications. Earlier forms of SOAP APIs used SMTP (Simple Mail Transfer Protocol), but that approach has fallen out of favor. You might still find it when using legacy systems.

Features of SOAP APIs

Why would a developer choose SOAP APIs over other types of APIs?

Some essential features of SOAP API include:

  • Heightened security that uses SSL support and WS-Security.
  • Wide bandwidth that doesn’t tend to get “stuck” as easily as some types of APIs.
  • Conforms to ACID (Atomicity, Consistency, Isolation, Durability) compliance, which can also improve security.

SOAP APIs take more time to set up than REST APIs, but they work well for organizations that need to prioritize security and have the resources necessary to manage protocols.

SOAP is considered an API protocol. A big advantage that REST API has over SOAP API is that REST can use the SOAP protocol.

Open APIs

Open APIs (also called “public APIs”) are the least strict types of APIs because anyone can use them. They’re the API response to open-source software. They don’t cost anything for people to use, and anyone can benefit from them. Google Maps is a good example of an open API. Anyone can go to Google Maps, enter an address, and find the location. The information you submit and the location you receive both pass through an open API.

Why would a company use open API? These types of APIs can offer several benefits. In a previous post, we went into the details of how open APIs can help organizations:

  • Generate leads
  • Develop a community of users (and improve brand awareness)
  • Improve transparency
  • Demonstrate goodwill that attracts potential collaborators

Are you interested in creating and managing open REST APIs without learning a lot of code? DreamFactory lets you manage low-code APIs from an intuitive, user-friendly dashboard. Start your free trial now.

Private APIs

Private APIs are internal APIs that only people within your organization can use. Users will need an API key for account authentication before they can access information guarded behind these types of APIs.

Private APIs have several advantages for organizations that do not want to share data or microservices with the public. You don’t even need to make endpoints visible on the internet. Instead, you can store your private APIs on internal systems.

The obvious disadvantage of this approach is that it becomes more difficult to share information and web services when you want to.

Partner APIs

Partner APIs let you share information and microservices with business partners without compromising security. With these types of APIs, business partners need authentication keys that give them access. Other than this feature, they largely offer the same functionality as private APIs.

Hybrid API Use Cases

Organizations often utilize a combination of different API types to optimize their applications’ functionality and user experience. This hybrid API approach leverages the unique strengths of each API type, facilitating a more dynamic and responsive service architecture. Below are some practical scenarios where different types of APIs are used together within the same ecosystem:

Real-Time Data and Standard Web Services

A common hybrid API scenario involves using REST APIs in conjunction with WebSocket APIs. REST APIs are perfect for standard client-server communications where the client requests data and the server responds. However, for real-time functionality, where the server needs to push updates to the client actively without the client having to request it each time, WebSocket APIs are invaluable.

For example, in a financial trading platform, REST APIs can handle transactions and retrieve user account details, which do not require real-time interaction. Simultaneously, WebSocket APIs can be used to provide real-time market data feed and notifications about market changes. This setup ensures that the platform delivers timely information crucial for trading decisions, enhancing the user experience by providing immediate data without needing to refresh the connection.

E-commerce Applications

In e-commerce, combining REST APIs and SOAP APIs can optimize the platform’s operations. REST APIs can manage user interactions like browsing items, adding to cart, and checking out, which benefit from REST’s stateless and scalable nature. On the other hand, SOAP APIs, known for their high security and reliability, can handle payment processing and transactions where data integrity and security are paramount.

This hybrid approach allows the e-commerce platform to be both user-friendly and secure, ensuring that customer interactions are smooth and their sensitive data is protected during transactions.

Healthcare Systems

Healthcare systems often integrate RESTful APIs and FHIR (Fast Healthcare Interoperability Resources) APIs to manage patient data effectively. REST APIs facilitate general data retrieval and patient management tasks, providing a flexible and easy-to-use interface for accessing electronic health records. FHIR APIs, designed specifically for healthcare information exchange, handle real-time data sharing among different healthcare providers, enabling seamless interoperability and access to critical medical information.

By employing both REST and FHIR APIs, healthcare applications can enhance the functionality and interoperability of their systems, leading to better patient outcomes through more coordinated care and efficient data management.

This hybrid API strategy enables a unified platform where users can interact seamlessly with a diverse array of devices, enhancing automation and user control in smart home environments.

By utilizing hybrid API strategies, companies can leverage the specific advantages of different API architectures, resulting in enhanced functionality, efficiency, and user satisfaction across various applications.

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How DreamFactory Can Help

DreamFactory makes it easy for you to create and manage REST APIs. If you have different types of APIs, DreamFactory can convert SOAP to REST. DreamFactory also helps solve the problems that you might encounter with REST and other types of APIs. For example, you can set API limits to prevent endpoints from getting too crowded and slowing down.

Experience the benefits of DreamFactory for yourself by starting a free trial.

Frequently Asked Questions (FAQ)

What are REST APIs?

REST APIs (Representational State Transfer APIs) are web APIs that use a stateless communication protocol, typically HTTP, to interact with applications. They are designed to handle data requests and responses using a standardized format like JSON or XML, making it easy for systems to communicate over the web.

How do REST APIs differ from SOAP APIs?

REST APIs are known for their simplicity and flexibility, using standard HTTP methods like GET, POST, PUT, and DELETE for operations. SOAP (Simple Object Access Protocol) APIs, on the other hand, are more rigid and secure, built with strict standards and capable of handling transactions that require a high level of security and reliability.

What are Open APIs?

Open APIs, or public APIs, are interfaces that are publicly available for any developer to use. They encourage external developers to create applications that can interact with the original platform, enhancing services and expanding functionality. A common example is the Google Maps API.

What is the purpose of Private APIs?

Private APIs are used internally within an organization to integrate different internal systems or to connect with trusted external partners. They are not available to the general public, which helps maintain control over the functionality and security of the system.

Can REST and SOAP APIs be used together?

Yes, REST and SOAP APIs can be integrated within the same application environment to leverage the benefits of both. This is common in complex systems where both flexibility and high-level security are required. For example, REST can be used for general user interactions while SOAP handles secure transactions.

What are the benefits of using Open APIs?

Open APIs help businesses expand their reach by allowing external developers to build on their platforms. This can lead to increased innovation, more robust community engagement, faster growth through third-party apps, and enhanced brand visibility.

When should a company choose to use Private APIs?

A company should opt for Private APIs when it needs to secure sensitive data or when the interactions are intended only for internal use. Private APIs help maintain control over the API’s usage and ensure that only authorized systems and partners can access critical functions.

Read More:

A Concise Introduction to REST API