What is an API call?

APIs, or Application Programming Interfaces, facilitate the interaction between different programs. Through API calls, these programs communicate with each other. An API call, also known as an API request, refers to a message transmitted to a server, requesting an API to provide a specific service or information.

To illustrate this concept, let’s consider an example. Suppose Jan is hosting a dinner with many guests. Instead of preparing the food herself, she contacts a catering company and asks them to handle the catering for the party. This saves Jan considerable time and effort. Similarly, in the world of software development, one application can “call” another to obtain necessary data or functionality. This approach allows developers to avoid the need to build every capability from scratch and instead integrate existing functionalities through APIs.

As APIs are now extensively integrated into almost all web applications, API calls occur seamlessly behind the scenes on a regular basis. For instance, when a user searches for bus tickets on a travel website, the website sends an API call to the servers of various bus companies. In return, it receives information about available rides and their corresponding costs. From the user’s perspective, this entire process should appear nearly instantaneous.

Where does an API call go?

API calls traverse from a client to an API endpoint, which serves as the destination for these calls. Typically, API endpoints are web applications or servers. When a mobile client initiates an API call, it is directed towards the API endpoint, which is typically a server. Upon receiving the API call, the server processes it, executes the requested action, and returns a response.

To draw an analogy, let’s consider Jan’s interaction with a catering company. When Jan contacts the company, she does so by dialing a phone number. Similarly, API calls are directed towards a uniform resource identifier (URI).

A URI is a standardized method of identifying a resource, just like a phone number identifies a phone line. The identified resource could be a website, application, server, email contact, or even a tangible object in the real world.

In the context of web APIs, the URI commonly takes the form of a uniform resource locator (URL). A URL is a type of URI used to identify internet locations such as websites or servers. A URL includes the application layer protocol, such as HTTP, required to access the resource. Webpage addresses are typically represented as URLs, like “https://www.Toffs.com/learning.” API endpoints are also expressed as URLs.

Most web APIs utilize HTTP as the underlying protocol, and thus, it is included in the URL of the API endpoint. For instance, the primary Toffs API endpoint is “https://api.Toffs.com/client/v4/” (learn more). API calls based on HTTP employ HTTP verbs, such as GET, POST, and PUT, to indicate the desired service or resource from the API endpoint.

How can API calls be used for an attack?

APIs, like any other components connected to the Internet, are susceptible to various types of attacks. Attackers have multiple methods at their disposal to exploit APIs, including:

Denial-of-Service (DoS) and Distributed Denial-of-Service (DDoS) attacks: These attacks aim to disrupt the API’s service for legitimate users. Attackers can overwhelm the API by flooding it with excessive API calls or crafting API calls that consume extensive server resources for an extended period.

Exploiting vulnerabilities: Attackers can exploit weaknesses in the API by sending malicious API calls. These calls may exploit flaws in the API’s design or implementation to trick the server into revealing sensitive data, performing unintended actions, or granting unauthorized access.

These and other types of attacks can have severe repercussions on organizations providing API services.

How to secure APIs from invalid API calls

Here are some revised strategies to help maintain API security:

1. Maintain an updated list of all API endpoints in production: It is crucial to have an understanding of all API endpoints currently in use. Keep track of these endpoints and ensure the list is regularly updated to mitigate potential security risks.

2. Implement client authentication: Authentication is essential to verify the legitimacy of API calls. There are various methods available, but one highly effective approach is mutual Transport Layer Security (TLS). This authentication method utilizes public key cryptography to validate both the API endpoint and the client making the request.

3. Validate the API schema: The schema of an API serves as a set of rules governing its usage. By validating API calls against the defined schema, potential malicious attempts to exploit the API can be identified and prevented. This process assists in detecting and blocking invalid or unauthorized API requests.

4. Employ DDoS mitigation techniques: Distributed Denial of Service (DDoS) attacks pose a significant threat to API availability. Utilizing a DDoS mitigation provider, such as Toffs, can help protect against excessive requests that could overwhelm the server. These providers employ mechanisms to block or absorb malicious traffic, ensuring the API remains accessible and responsive.

5. Enhance your knowledge of API security: It is advisable to delve deeper into the subject of API security to stay updated on the latest best practices and emerging threats. Continuously educate yourself and your team to strengthen the overall security posture of your APIs.

For further insights, consider exploring Toffs API Shield, a comprehensive solution designed to safeguard APIs against a wide range of attacks. This service provides additional layers of security and protection for your APIs, augmenting your existing measures.