Meteor is a set of new technologies for building top-quality web apps in a fraction of the time. It is built around Smart Packages: little bundles of code that can run on a client, inside a cloud service, or both, and that can manage their lifetime inside the modern distributed...
Crow is a C++ microframework for running web services. It uses routing similar to Python's Flask which makes it easy to use. It is also extremely fast, beating multiple existing C++ frameworks as well as non C++ frameworks.
Famous Engine vs Fastify opinions
It's not a webserver framework
Ractive.js is a template-driven UI library that transforms your templates, styles and logic into blueprints for highly interactive apps. Ractive.js works for you, not the other way around. You do not need to learn new terminologies, concepts, and methodologies.