As a maintainer of Hurl, I've been really curious about this product (while not affiliated at all)! It has been an interesting journey because I've seen how you can build something like this: first you start with a solid first simple iteration (just an editor of web script files), then slowly you add features around it and expand: a very good documentation, "chron" scripts, email alerts etc...

I'm using Skybear.net at work today to do web sites monitoring (SSL certificates and health check), simple but very effective... impressive for a one man work! I can see a future where (a lot of) other file format are supported (à la Postman, Bruno etc...), but I'm happy that Hurl has been chosen for starting.