Technical overview

The core tech

In brief, the main technologies behind Apostrophe are:

• Node.js: Popular server-side JavaScript runtime. We originally chose Node.js to achieve a fully-JavaScript development experience for developers. It has continued to improve over time, delivering high performance and powerful features we can use.
• Express: Un-opinionated Node.js web framework. Express is the most widely used web framework for Node.js. Because it is simple, un-opinionated, and well-known, it was straightforward to extend it to suit Apostrophe's needs.
• MongoDB: Document-based database engine. The db-connect layer provides a fluent JavaScript-based API across all three supported databases, so choose MongoDB primarily if you need MongoDB-specific query features beyond what db-connect covers. PostgreSQL is just as capable at scale and a great choice for a fully open-source stack, while SQLite is ideal for evaluating Apostrophe or running smaller sites with zero setup. See Choosing a Database for more detail.
• JSX: Recommended template language for page, widget, and component templates. JSX is real JavaScript with inline markup, so it brings modern editor support, real control flow, and accurate error reporting — with no separate front-end project required. Existing projects can convert to it incrementally, template by template, since a JSX template can extend or include a Nunjucks one. Nunjucks — a richly featured template language with a syntax nearly identical to Twig, Jinja, and other Django-inspired templating languages — remains fully supported for projects that use it.

Directory structure

There are a few directories and top-level files that are especially important in Apostrophe projects. Here is a rough overview of these files and folders you will see in the official boilerplate, starter-kit-essentials.

Folder/File	What is it?
app.js	The heart of the application. This is where you tell Apostrophe what modules are in your project and set a few top-level parameters.
/modules	All project-level modules and configuration for installed modules.
/public	Public, static files (not managed through the CMS). Apostrophe will generate specific directories inside, but you can also use it as needed.
/views	Template files that do not belong to any one module. Apostrophe looks for site wrapper templates here, including layout.jsx (or layout.html in a Nunjucks project).

TIP

Core module configuration is all done in a subdirectory of modules: modules/@apostrophecms. This keeps core modules organized together and out of the way, following the npm scoping pattern.