Mutual TLS Security Scheme in OpenAPI

Mutual TLS (mTLS) is a security protocol that enhances the security of API communication by requiring both the client and server to authenticate each other using digital certificates. This two-way authentication ensures that only trusted parties can establish a connection, providing an additional layer of security.

OpenAPI lets you define a Mutual TLS security scheme using the mutualTLS type.

Defining a Mutual TLS Security Scheme

To define a Mutual TLS security scheme in OpenAPI, you can use the following structure:

There are no additional fields required for the mutualTLS type, it is purely there to indicate that the API requires mutual TLS authentication. The description field can be used to provide additional information about who to talk to for a certificate, or what the process is for obtaining a certificate.

Learn more about Mutual TLS in the OpenAPI Specification , or on Cloudflare’s What is Mutual TLS .