Web APIs

Web APIs are interfaces that allow web applications to communicate with external services or data sources over the internet.

1.REST API

• REST APIs use standard HTTP methods & are stateless. They
  typically return data in JSON or XML format.

• Used for web services, where resources are accessed via URLs.Commonly used for CRUD operations on data.

• Example: GitHub API, Twitter API.

2.SOAP API

• SOAP is a protocol that uses XML for message format & typically relies on HTTP or SMTP for message negotiation & transmission.

• Enterprise-level applications requiring security, reliability, and
  formal contracts (WSDL).

• Example: Payment gateways, financial services APIs.

1. GraphQL API

• GraphQL allows clients to request exactly the data they
  need, and nothing more. It uses a single endpoint and
  provides more flexibility compared to REST.

• When you need efficient querying of complex datasets, or when working with mobile applications where bandwidth
  is a concern.

• Example: Facebook's GraphQL API, Shopify API.