Best Practices for REST API Security

REST APIs

REST APIs allow you to perform CRUD (create, read, update, and delete) operations between a client and a server. It is the most common type of API, and almost 80% of all public APIs are REST. Many people even confuse the term API with the REST API. Therefore, it is crucial to ensure that REST APIs follow the security standards to avoid vulnerabilities.

Best Practices for REST API Security

Here are some good practices to ensure a robust and secure REST API implementation.

Implement Authentication

You should always be aware of who is calling your APIs. Validating the clients of an API to identify if they are who they claim to be is called API authentication. OAuth 2.0 (Open Authorization) is a standard developed to allow a user access to resources from a third-party application. It is an authorization protocol designed only to grant access to resources, and it works by using access tokens.

The access token is information that provides authorization to access resources on behalf of the user. Usually, we can use the JSON Web Token (JWT) format for the access token. Implementing an Auth standard like OAuth 2.0 ensures proper authentication because the user's identity is validated, unlike API keys, where only the application's identity is validated.

Use TLS (HTTPS)

API keys and authentication parameters may be compromised during server-client communication. Therefore, it is critical to use Transport layer Security(TLS) which protects the information by encrypting it. A quick way to check TLS availability is to see if the URL starts with HTTPS. If it does, then it means that TLS is enabled. SSL, the predecessor of TLS, can also be used for the same purpose.

Validate API Parameters

REST APIs use path, query, request body, and header parameters to pass information from the client to the server. These parameters must be validated to ensure that they don't comprise security. We can do it by establishing a schema for incoming parameters and validating the parameters against the schema.

Rate Limiting

A large number of requests within a short time are computationally expensive and may render your API unresponsive. Luckily, we can limit the number of requests a client can make to the API in a specific time window. This process is called rate limiting. Rate limits are crucial to prevent excessive use and brute force attacks like DDoS.

Implement Content Types

Implement content-type checking by defining the allowed content types in your REST API using the Content-Type and Accept headers. The Content-Type header specifies the type of data sent to the server. The Accept header specifies the type of data the client expects to receive from the server. As a result, all requests that do not correct types will be rejected to prevent potential attacks.

Restrict Access to Resources

Restrict non-permitted HTTP methods to avoid unauthorized access to resources. We can do this by specifying the allowed HTTP methods like GET, POST, etc., and restricting any request that uses other HTTP methods.

Use Pagination

If the API returns large amounts of data, it is always good to use pagination. It allows the client to limit the number of resources they can access in a single request. We can also establish pagination limits to define the maximum number of resources a client can access in a single request. If we don't use pagination, a request for all the resources in an extensive collection may slow down or crash the server.

Final Note

That's pretty much it. We hope that this guide will help you keep your REST API secure and performant.