What are some alternatives?
When comparing Strapi and Sanity.io, you can also consider the following products
Contentful - You don't need another CMS. You need a better way to manage content — unified, structured, and ready to deploy to any digital channel.
WordPress - WordPress is web software you can use to create a beautiful website or blog. We like to say that WordPress is both free and priceless at the same time.
Prismic - prismic.io is a web software you can use to manage content in any kind of website or app. API-driven.
GraphCMS - The GraphQL Headless CMS
Butter CMS - API-first CMS + blog platform built for developers & marketers.
Storyblok - API-based content management system for multi-device online publishing