single-spa is a JavaScript framework for bringing together multiple micro frontends in a single front-end application. Although we advise against micro frontend anarchy, the use of micro frontends as an excuse to mix and match multiple frameworks, single-spa supports just that. We understand that there are legitimate scenarios such as upgrading to a new revision of a framework across multiple micro frontends where integration across multiple frameworks is necessary. single-spa has been a go-to framework for micro frontend integration for our teams, and they're finding it to work well with SystemJS and managing different versions of a single dependency.
single-spa is a JavaScript metaframework that allows us to build micro frontends using different frameworks that can coexist in a single application. In general, we don't recommend using more than one framework for an application, but there are times when we can't avoid doing so. For instance, single-spa can be quite useful when you're working with a legacy application and you want to experiment by developing a new feature, with either a new version of the existing framework or a completely different one. Given the short life span of many JavaScript frameworks, we see a need for a solution that would allow for future framework changes and localized experimentation, without affecting the entire application. single-spa seems to be a good start in that direction.
