Faith & Code | Reflections by Errong

Making Mutual SSL (mTLS) API Requests in Node.js Mutual TLS (mTLS) is a common security requirement in enterprise environments. Unlike regular HTTPS (where only the server is authenticated), mTLS requires both the client and the server to authenticate each other using certificates. This guide focuses on using Node.js as a client to call an API protected by mutual TLS. It also covers a very common real-world problem: Your Ops or Security team gives you a .jks file JKS is designed for Java / Spring Boot Node.js needs .key , .crt , and .pem files instead We’ll walk through converting the JKS file and using it in Node.js step by step. What Files Does Node.js Need for Mutual TLS? To make an mTLS request from Node.js, you typically need: client.key – your private key client.crt – your client certificate ca.pem – the Certificate Authority (CA) chain to trust the server These are passed to Node’s HTTPS agent. Step 1: Convert JKS to PKCS12 (...