What is a private API?

Examples of private APIs

Private APIs are a common type of API used by many organizations.

One popular type is a data retrieval API. These APIs automatically collect data from a variety of sources, including databases and internal systems, upon request. There's no need for users to write custom code to individually interact with each source. In addition to automating data collection and retrieval, these APIs also ensure the accuracy of the data being collected. Once the data is retrieved, it becomes accessible for analysis and insights generation. Other applications can also use the data as needed.

User authentication APIs are another example of private APIs. These APIs verify user identities and ensure that only authorized personnel can access or interact with specific enterprise resources. These APIs may support one or more identity protocols, such as OpenID Connect, OAuth 2.0, Financial-grade API and Ssecurity Assertion Markup Language, and often offer user-friendly endpoints that enable users to sign up, log in/log out, and access APIs. Authentication APIs are often served over HTTPS.

A third example of private APIs is a workflow automation API. These APIs enable organizations to automate repetitive tasks, like task scheduling and reports generation, and streamline complex workflows, enabling employees to save time, reduce errors and focus on other more strategic initiatives. Workflow automation APIs also facilitate the seamless integration of applications with existing systems without requiring complex coding.

Organizations can also develop notification and alerting APIs. These private APIs send notifications to users to inform them about specific events or updates. To ensure that notifications are sent in a timely manner, triggers or events must be predefined. When the API detects the trigger, it immediately sends a notification to the user.

Private API use cases

Private APIs are ideal for scenarios where internal data sharing is required and where there is a need to break down data silos. By developing private APIs, different departments in an organization can share data. Similarly, different applications can also share data.

Private APIs support internal application development. These applications may need to access the organization's data and services to function correctly. Private APIs facilitate this access.

Another possible use case for private APIs is the integration of legacy systems with newer systems. With private APIs, organizations can modernize their technology infrastructure without having to completely overhaul it. In doing so, they can speed up modernization, save on modernization costs and retain access to valuable data.

Advantages of private APIs

Since private APIs are intended for internal use, they enable organizations to set it up in a way that best meets their specific requirements. Additionally, they can retain complete control over their data and services.

Private APIs can be set up for a wide range of enterprise use cases in many different departments, including marketing, sales and human resources. These APIs help to break down data silos, facilitating information sharing and easing collaboration among users and departments.

Private APIs are more secure than public APIs and open APIs since they are not exposed to external threats. Moreover, they can be secured by applying appropriate internal security protocols and implementing an extensive governance process. As part of this process, the APIs can be placed in a centralized API library or portal. To access the APIs, users -- e.g., developers -- need to be assigned security credentials. They must also be properly authenticated to prevent API access by unauthorized or malicious users.

Drawbacks of private APIs

One common drawback of private APIs is complexity. Since these APIs are specific to an organization and often require a lot of customization, developing them can be a complex process.

In addition, they may require significant support resources, increasing the maintenance burden and cost for the organization.

Private APIs can also reduce possibilities for collaboration between different organizations. This can curtail innovation and limit the opportunities to develop new products and services.

Private APIs vs. public APIs, composite APIs, partner APIs and open APIs

Public APIs

Private APIs contrast with public APIs, which are services that provide outside access to internal resources. Intended to facilitate broad consumption of certain types of data or services, public APIs are often publicly and freely available to developers and other users. The offering parties rarely place any restrictions on the use of public APIs.

The following are examples of public APIs:

• Social media APIs, such as Facebook Graph API, X API and YouTube Data API. Social media APIs enable developers to programmatically interact with social platforms to perform various actions, such as embed YouTube videos, manage content on Facebook and Instagram, or publish content to multiple social profiles using a single API.
• Weather APIs, such as Weatherstack. These APIs cover global weather data, enabling weather services to instantly retrieve accurate weather data for any worldwide location.
• Foreign exchange APIs, like Fixer API. These APIs source currency data from trusted sources, enabling developers and organizations to access current and historical foreign exchange rates for a wide range of world currencies.
• Stock market APIs, like Marketstack. These are financial market data APIs that deliver worldwide stock market data using a user-friendly representational state transfer (REST) interface in a simple JavaScript Object Notation format.
• Internet Protocol address lookup APIs, like IPstack. These IP geolocation APIs provide IP information to global IP database services, enabling them to strengthen network security and improve customer user experiences.

Composite APIs

Composite APIs combine and integrate multiple APIs to provide access to data or services that a single API alone cannot provide. These APIs also combine multiple API requests to access the required data or service into a single -- or a few -- API call(s), thus increasing app efficiency and saving on data usage. In addition, they can be customized to satisfy an application's specific needs.

Composite APIs are often used in microservices environments where information from several services is needed to perform a task. They are also common in e-commerce. E-commerce platforms use composite APIs to simultaneously and correctly execute various actions performed by a user, such as finding an item, adding it to the cart, going to checkout and making the payment.

Some other popular applications of composite APIs are financial services (to provide access to market data and financial analytics), healthcare (to provide access to patient data and medical research), hospitality (to simplify reservations for rooms and tables) and transportation (to provide access to traffic and weather data).

Partner APIs

Another type of API is a partner API. These APIs are intended for consumption by specific users or groups of users and are not publicly available. To use partner APIs, the users must be authenticated and authorized to use specific protocols.

Many companies provide partner APIs for specific audiences. These include the following:

• Stripe. Numerous businesses use Stripe's partner API to process payments.
• Salesforce. Salesforce's partner API enables Salesforce partners and customers to integrate the Salesforce customer relationship management platform with their other business applications.
• Microsoft. Microsoft's Partner Center REST APIs enable Microsoft partners to manage customers, subscriptions and orders.
• Shopify. Shopify's GraphQL partner API enables the company's partners to access transaction data and use this data to implement useful automations in front-office and back-office operations.
• Airbnb. Airbnb offers a partner API that enables its partners to connect their booking software with the Airbnb platform and integrate Airbnb reviews or content into their website or app.

Open APIs

Apart from these four types of APIs, there is another type: open APIs. Open APIs are commonly used to provide access to data or services. These APIs are open to the public and free to use. That said, some open APIs require users to register and use API keys to authenticate themselves.

Open APIs are usually well documented and user-friendly. Since they are intended for widespread consumption, they foster innovation, experimentation and learning. Developers can use the data and services provided by open APIs to develop new applications.

APIs are essential for modern applications, so companies should ensure API security from the start. Use these guidelines to design, deploy and protect your APIs.