I’ve recently been investing a lot of time developing new features for Lynk and our most requested feature has been request capture and playback. This means being able to see the individual HTTP requests and responses going through the Lynk Tunnel (more information available here) but also being able to replay them as you change your code without having to go through the web browser each time.

This feature is especially useful when developing REST APIs since it allows you to quickly see how your application responds to various iterations of your code. Ngrok, the existing alternative to Lynk already offers this feature (including request playback) so it made sense to develop this for the upcoming beta release.

However, we didn’t want to keep this feature limited to Lynk. Having the ability to capture and replay requests through both a backend API and frontend UI makes sense for many applications — regardless of if they’re hosted through Lynk.

This is why it made sense to develop Parasite — a standalone proxy server which allows you to intercept, record, and replay incoming HTTP traffic. It’s also completely Open Sourced on our Github.

Parasite is also available as an NPM package and today I’ll walk you through embedding it in an ExpressJS API.