Directory Structure

Api: Contains the V8 API layer, built on JSON API specification. Includes core framework and versioned API controllers. See V8 API documentation for usage.
cache: Contains cache files used by SuiteCRM including compiled Smarty templates, grouped vardefs, and minified JavaScript. Some modules and custom modules may also store temporary module-specific data here.
custom: Contains user and developer customisations to SuiteCRM. Customisations placed here are preserved across upgrades. See Extensions for the recommended structure.
data: Stores the classes and files used to work with SugarBeans and their relationships.
include: Contains the bulk of non-module, non-data SuiteCRM framework code.
install: Code used by the SuiteCRM installer.
jssource: Contains the unminified source of JavaScript files used within SuiteCRM.
lib: Internal libraries and utilities used by SuiteCRM, including the Robo build/CLI tooling, search integration, PDF handling, and logging utilities. See CLI Tools for available Robo commands.
metadata: Stores relationship metadata for the various stock SuiteCRM modules. Not to be confused with module metadata, which contains view, dashlet and search definitions.
ModuleInstall: Code for the module installer (used by the Module Loader in the admin panel).
modules: Contains the code for all stock SuiteCRM modules. Custom modules are also placed here.
public: Web server document root for file uploads and user-facing assets such as profile photos.
service: Code for the legacy SuiteCRM SOAP and REST v4/v4.1 APIs. For new integrations use the V8 API in Api/.
tests: The test suite. Contains unit, acceptance and API tests run via Robo commands. See CLI Tools.
themes: Code, data and images for the bundled SuiteCRM themes.
upload: Contains documents uploaded to SuiteCRM. File names correspond to the ID of the matching Document Revision or Note record. upload/upgrades also stores upgrade packages and installed module packages.
vendor: Composer-managed third-party dependencies. Do not modify directly.
soap, XTemplate, Zend: Source code for legacy third-party libraries bundled with SuiteCRM. These are deprecated and will be removed in a future version.