Introduction to API

Introduction to API

What is an API?

• API stands for Application Programming Interface
• Set of definitions and protocols to build and integrate application software
• Helps in interaction between multiple software intermediaries
• Provides flexibility, simplify design, administration and use
• Open up access to your resources while maintaining security and control

Different Types of API:

1. Web APIs: APIs which can be accessed over internet using HTTP protocol. The API defines endpoints, and valid request and response types.

2. Open APIs: These APIs are available to developers with minimum restrictions. They may require registration, use of an API key or OAuth, or may be completely open.

3. Partner APIs: These APIs are not available publicly and need specific entitlements to access them. There is an on-boarding process with a specific validation workflow to get access to partner APIs.

4. Internal APIs: These APIs are hidden from external users and only exposed by internal systems.

5. Composite APIs: They combine multiple data or service APIs. Composite APIs are useful for example in a micro-services architecture pattern where you need information from several services to perform a single task.

What is Web Services ?

• It is a service through which different systems can communicate with each other via the internet.
• In web service, HTTP is used to transfer machine-readable file formats such as XML and JSON
• Every web service is an API but every API is not a web service
• Two types of web service – REST and SOAP