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API. What is an API?

API is the acronym for Application Programming Interfaces. An API is a set of definitions and protocols that allow communication links to be established between two different applications based on a set of predefined rules.

Therefore, an API is nothing more than an intermediate layer used between two sources of information to facilitate the exchange of information between two applications and, based on the features it offers, the exchange of information is accepted or not. To do this, the API owner grants permissions to third-party developers and limits or grants them access to certain areas of their application.

1. Advantages of APIs

Without a doubt, the main benefit of using an API is that it makes developers’ work more comfortable, saving them time in the creation of their applications since it already offers them the possibility of making calls to parts of other applications and retrieving information from it in real time.

For example, the Mailrelay API allows you to integrate any of your systems for sending and retrieving information from your Mailrelay account (without the need to access our web interface and process this information locally). In the same way, when you click to make a payment by credit card or Paypal using the bank API or Paypal API, a query is sent to their platform to confirm whether you have enough money to complete the purchase or the transaction should not be accepted.

2. Types of APIs

The four main types of API are:

– Open APIs.
They are also known as external or public APIs. These are the APIs with the most relaxed security measures and this makes it easy for developers and external users to access the desired data, even without restrictions and their use is free of charge.

– Partner APIs.
Partner APIs are not publicly available and require a license to use them. They are used to give data access to specific business partners using a more secure API and include robust validation protocols.

– Internal APIs.
Internal APIs, also called private APIs, are internal APIs that are hidden from third parties and their raison d’être is to improve communication within an organization (between departments and between different sites). Internal APIs have security measures to ensure access only to employees with the appropriate permissions.

– Integrated or mixed APIs.
A mixed API, as its name suggests, is a combination of different APIs that integrate and combine data for the desired performance. They are the most used in microservices, where several services are required to execute a specific operation.
They are an all-in-one solution to improve performance and data flow.