What are the 4 types of API?

The four main types of APIs are categorized based on their intended use and how they are shared and accessed. Here’s a breakdown of each type:

1. Open APIs (Public APIs)

• Description: Open APIs are publicly available to external developers and users. These APIs are designed to be shared freely and allow third-party developers to interact with the services or data of an organization.
• Examples: Google Maps API, Twitter API, Facebook Graph API.
• Use Case: Open APIs are commonly used for external integrations, such as embedding Google Maps in a website or enabling social media logins.

2. Partner APIs

• Description: Partner APIs are shared with specific third parties, usually through a business relationship or contract. These APIs are not open to the public but are provided to strategic partners to enable business-to-business (B2B) interactions.
• Examples: Payment gateways (e.g., PayPal), travel booking platforms that collaborate with airlines or hotels.
• Use Case: Partner APIs are typically used in collaborations between companies, such as enabling secure data exchange or processing transactions.

3. Internal APIs (Private APIs)

• Description: Internal APIs are used within an organization to enable internal systems and teams to interact with each other. These APIs are not exposed to external users and are designed to improve efficiency within the organization.
• Examples: APIs that connect internal HR systems with payroll software or internal tools that manage company data.
• Use Case: Internal APIs help streamline operations, automate processes, and ensure different departments or systems within the same organization can communicate effectively.

4. Composite APIs

• Description: Composite APIs allow developers to bundle multiple API calls into a single request. This type of API is particularly useful when interacting with complex systems that require multiple resources or services to be called at once.
• Examples: A composite API might handle a customer order by retrieving user data, order details, and inventory status in one API call.
• Use Case: Composite APIs are useful when performing complex workflows or data retrieval that involve multiple services.

Each type of API serves a specific purpose, whether it's enabling third-party integrations (open or partner APIs) or streamlining internal processes (internal and composite APIs).

Sources:

• MuleSoft: API Types
• IBM: Understanding APIs