{"id":72233,"date":"2023-07-27T14:56:58","date_gmt":"2023-07-27T14:56:58","guid":{"rendered":"https:\/\/mailrelay.com\/glossary\/api\/"},"modified":"2026-09-28T12:58:24","modified_gmt":"2026-09-28T12:58:24","slug":"api","status":"publish","type":"glossary","link":"https:\/\/mailrelay.com\/en\/glossary\/api\/","title":{"rendered":"API"},"content":{"rendered":"\n

API is the acronym for Application Programming Interfaces<\/em>. 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.<\/p>\n\n

Therefore, an API is simply an intermediate layer placed between two sources of information to make it easier for two applications to exchange information, and whether that exchange takes place depends on the features the API offers. To do this, the API owner grants permissions to third-party developers and limits or grants them access to certain areas of the application.<\/p>\n\n

1. Benefits of APIs<\/h2>\n\n

Without a doubt, the main benefit of using an API is that it makes developers’ work easier, saving them time when building their applications, since it lets them call parts of other applications and retrieve information from them in real time.<\/p>\n\n

For example, the Mailrelay<\/a> API makes it easy to integrate any of your developments to send and retrieve information from your Mailrelay account (without needing to access your account’s web interface and process that information locally). In the same way, when you are about to make a payment by card or Paypal using the bank’s API or Paypal’s API, a query is made to check whether you have enough money to complete the purchase.<\/p>\n\n

2. Types of APIs<\/h2>\n\n

The four main types of API are:<\/p>\n\n

– Open APIs<\/strong>.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.<\/p>\n\n

– Partner APIs<\/strong>.Partner APIs are not publicly available and require a license to use them. They are used to give specific business partners access to data in a more secure way and include robust validation protocols.<\/p>\n\n

– Internal APIs<\/strong>.Internal APIs, also called private APIs, are internal APIs that are hidden from third parties and their purpose 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.<\/p>\n\n

– Composite APIs<\/strong>.A composite API, as its name suggests, is a combination of different APIs that integrate and combine data for the desired performance. They are most commonly used in microservices, where several services are needed to perform a specific operation.They are an all-in-one solution to improve performance and data flow.<\/p>\n\n

Related entries<\/h2>\n\n