There's also Sanity, which supports self-hosting of the app itself and is mostly open source: https://www.sanity.io https://www.sanity.io (Disclosure: I'm inv

There's also Sanity, which supports self-hosting of the app itself and is mostly open source: https://www.sanity.io https://www.sanity.io (Disclosure: I'm involved in the company, but not in a major way.)