Free Software for JavaScript
FireCMS
A free and open-source, firestore-based, headless content management system. WIth FireCMS can manage content through an intuetive admin panel that generate CRUD views based on your configuration. FireCMS is built with Typescript, Firebase, React + React Router, Material UI, Formik + Yup and aims to increase productivity for both developers and administrators managing content.
Mura
The Mura CMS platform makes it easier & faster to build and update websites. The content management system was created to free content managers from distraction of multiple tools, the worry of steep learning curves, and a clear need to tell the right story, to the right audience, at the right time. Mura is loved by content managers, content contributors, marketers and developers alike.
Cockpit
Cockpit is a self-hosted headless and api-driven CMS. With Cockpit you can manage any structured content for your website, web app or mobile application. Cockpit's intuitive dashboard allow anyone to manage content without technical skills and is a perfect match for developers and teams looking to improve they content management situation. Cockpit allow you and your team to setup a content management system for static sites and JavaScript-based front-ends in no-time.
TinaCMS
Tina is an open-source site editing toolkit and headless CMS for React-based sites like Gatsby & Next.js
Storyblok
A headless & API-based CMS with an opt-in head and a visual editor. With Storyblok you can manage your content through an intuitive dashboard and access that data though the content delivery API, as nested JSON. Storyblok is an open-source software and can be used as such, but is also provided as a commercially hosted, cloud rendering service. As a front-end developer you can choose to work with any template engine, framework or system of your choice.
DatoCMS
Connect DatoCMS to your favorite site generator, build the perfect backend and deploy anywhere you like.
GDevelop
GDevelop is a 2D cross-platform, free and open-source game engine that takes visual programming to the next level. GDevelop allows you to take read-made behaviours and add them to your game objects or create new once with intuitive and east to use events. With GDevelop, it is easy to make games for PC and Mobile, as well as launch HTML5 games playable right in your web browser.
RxDB
RxDB is short for Reactive Database and is a NoSQL-database for JavaScript Applications like Websites, hybrid Apps, Electron-Apps, Progressive Web Apps and NodeJs. Reactive means that you can not only query the current state, but subscribe to all state changes like the result of a query or even a single field of a document. This is great for UI-based realtime applications in way that makes it easy to develop and also has great performance benefits. To replicate data between your clients and server, RxDB provides modules for realtime replication with any CouchDB compliant endpoint and also with custom GraphQL endpoints.