The Definitive Guide to REST API Security: Best Practices

Rosie Brooks
by Rosie Brooks on May 10, 2023 8 min read

In the contemporary digital landscape, APIs have gained an unprecedented level of significance, with the emergence of integrated web and mobile-based offerings necessitating extensive data sharing across products. As reliance on APIs surges, so does the risk of associated security challenges, including faulty authentication, authorization, and inadvertent disclosure or compromise of data.

In light of the 2022 API Security Trends Report, 41% of organizations surveyed suffered an API security incident over the past year, with 63% of those cases culminating in data breaches or losses. This article will provide you with REST API security practices to safeguard you from threats.

What is a REST API?

In technical parlance, the Representational State Transfer Application Programming Interface, or REST API, is a protocol used for accessing web services by employing HTTP requests to retrieve, modify, and delete data. It is based on the REST architectural style, characterized by its ability to transfer representations of resources between systems without retaining any context on the server between requests. In other words, each request contains all the necessary information to complete the task. Consequently, REST API serves as a crucial component of modern web architecture, facilitating the exchange of data between web applications and mobile devices.

In simpler terms, REST API is a set of rules for building web applications that can interact with each other. It allows developers to create applications that can communicate with other applications regardless of the programming languages or platforms used to create them. For instance, REST API can enable an e-commerce application to retrieve product information from a separate database application and display it to users. In essence, REST API is like a translator that helps different software programs talk to each other and exchange information without compatibility issues.

Why REST API Security is so Important

As APIs are used to expose sensitive data and business logic to third-party applications and services, security is a crucial aspect that should not be overlooked. REST API security is essential to ensure the confidentiality, integrity, and availability of data exchanged between different systems.

A compromised API can lead to a range of security threats, including data theft, unauthorized access, and denial-of-service attacks. Hackers can exploit vulnerabilities in poorly secured APIs to gain access to sensitive information, manipulate data, or inject malicious code into the target system.

The consequences of a successful API attack can be significant, ranging from financial loss to reputational damage. Moreover, regulatory compliance requirements, such as HIPAA, GDPR, and PCI DSS, mandate secure API practices to safeguard sensitive data.

Therefore, it is crucial to implement robust security measures to protect REST APIs from potential threats. Security mechanisms such as authentication, authorization, encryption, and input validation can help mitigate the risks of API attacks and ensure the secure exchange of data between systems.

What are REST API Security Best Practices?

When designing and implementing REST APIs, security should be a top priority to ensure that sensitive data is protected from potential attacks. Here are six best practices for REST API security:


Using HTTPS is a fundamental best practice for REST API security. It is the standard protocol for secure communication over the internet and employs SSL or TLS to encrypt data transmitted between the client and server. This means that any sensitive data exchanged between systems is protected from eavesdropping, tampering, and data theft. To achieve HTTPS, you need to get an SSL certificate and configure it for your server. Once configured, all API requests and responses will be encrypted, ensuring that your API is secure.

In addition to encrypting data, HTTPS also provides authentication and integrity checks. The SSL/TLS protocol verifies that the server is who it claims to be, also preventing man-in-the-middle attacks. It also ensures that the data has not been tampered with during transit, providing integrity protection. By using HTTPS, you can establish a secure communication channel between the client and server, thus providing a strong foundation for your REST API security.

Implement Authentication and Authorization

Authentication and authorization are critical components of REST API security. Authentication verifies the identity of the client requesting access to the API, while authorization determines whether the client has permission to perform a particular action. By implementing these security mechanisms, you can ensure that only authorized users have access to your API resources.

OAuth 2.0 and JSON Web Tokens (JWT) are two popular authentication and authorization protocols that you can use to secure your API. OAuth 2.0 is an open standard for authorization that allows users to grant third-party applications access to their resources without sharing their credentials. JWT, on the other hand, is a compact, self-contained format for securely transmitting information between parties as a JSON object. It provides a secure and efficient way to exchange information, including authentication and authorization data, between the client and server.

Password Policy as a Best Security Practice

Passwords are the first line of defense against unauthorized access to API endpoints. To ensure that passwords are secure, they should be complex, unique, and stored in a secure manner. Password policies such as password expiration and complexity requirements can help enforce these best practices.

Validate User Input

Input validation is essential to prevent injection attacks such as SQL injection and cross-site scripting (XSS). By validating user input, you can ensure that API requests contain only expected data types and values, preventing malicious input from executing unauthorized code or accessing sensitive data.

Limit Rate and Access

Limiting the rate and access of API requests can help prevent denial-of-service (DoS) attacks and protect against unauthorized access. By implementing rate-limiting and throttling, you can ensure that API resources are used efficiently and effectively.

Regularly Update and Patch Your System

Software vulnerabilities are constantly being discovered and exploited by attackers. To mitigate these risks, it is crucial to regularly update and patch your system, including APIs and underlying infrastructure. By keeping your system up-to-date, you can prevent known vulnerabilities from being exploited by attackers.

What are Advanced REST API Security Best Practices?

While the above best practices are essential for securing REST APIs, there are additional measures that can be taken to enhance security. Here are three advanced REST API security best practices:

Implement two-factor authentication

Two-factor authentication (2FA) is an advanced security measure that adds an extra layer of protection to your REST API. It requires the user to provide a second form of identification, such as a code sent to their mobile phone or a biometric identifier, in addition to their username and password. By implementing 2FA, you can ensure that only authorized users are granted access to your sensitive API resources.

2FA significantly reduces the risk of account compromise by making it much harder for attackers to gain access to your API. Even if an attacker manages to steal a user’s password, they will still need to provide the second factor of authentication to access your API. This makes it much more difficult for attackers to gain unauthorized access to your API resources, even if they have stolen a user’s password.

Use API gateways

API gateways are another advanced security measure that can help enhance the security of your REST API. An API gateway acts as a mediator between the client and API endpoints, allowing you to enforce security policies and apply additional security measures such as rate-limiting, caching, and monitoring. By using an API gateway, you can centralize API security management and reduce the risk of unauthorized access.

API gateways provide several benefits for REST API security. They allow you to implement security policies such as authentication and authorization at a single location, simplifying the management of your API security. They also provide additional security features such as rate-limiting and caching, which can help prevent attacks such as DDoS and improve API performance.

By using an API gateway, you can also implement monitoring and logging, providing valuable insights into how your API is being used and identifying potential security threats. Overall, API gateways are a powerful tool for enhancing the security of your REST API, allowing you to implement security policies and apply additional security measures in a centralized manner.

Implement threat modeling

Threat modeling is an advanced security practice that involves systematically analyzing the attack surface of your REST API and identifying potential security threats. By proactively identifying and mitigating potential threats, you can significantly enhance the security of your API.

The first step in threat modeling is to identify the assets that are most valuable to your API, such as sensitive data or critical functionality. Once you have identified your assets, you can then identify potential threats and vulnerabilities that could be used to compromise them. This could include attacks such as SQL injection, cross-site scripting, or API enumeration attacks.

Once you have identified potential threats, you can then prioritize mitigation measures to address them. This could include implementing additional security measures such as authentication and authorization, input validation, and rate-limiting. By proactively identifying and mitigating potential threats, you can significantly enhance the security of your REST API and reduce the risk of successful attacks.


In conclusion, securing REST APIs is essential to ensure the confidentiality, integrity, and availability of data exchanged between different systems. To mitigate the risks of API attacks, it is crucial to implement robust security measures such as HTTPS, authentication, authorization, input validation, and rate limiting. Moreover, advanced security measures such as two-factor authentication, API gateways, and threat modeling can enhance the security of REST APIs. By following these best practices, organizations can safeguard their APIs against potential threats and ensure a seamless user experience while complying with regulatory requirements.

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