Given the raise of CI/CD, I really think these kind of tools (CLI tests on HTTP requests), based on a simple format, will be really important. We've build Hurl (https://github.com/Orange-OpenSource/hurl), that shares a lot of similarities with Step CI (plain text instead of yaml, captures, jsonpath, xpath etc...). I will shamelessly take inspiration for some new features (like GraphQL for instance)!
Our Matcher functionality was actually inspired by Hurl (you call them predicates!)! We would take your inspiration from us as a huge compliment :)
The main difference between Hurl and Step CI is from our persepective an ideological one. What do you think?
Hurl is a CLI tool, while Step CI is a library. This means that you can include our Test Runner (https://github.com/stepci/runner) and use it with other tools. For example, you can combine it with testing frameworks like Mocha, Jest, and Ava (https://github.com/stepci/stepci/blob/main/docs/using-test-t...) or build your own platform on top of it.
That's what's so nice about open source.