vtiger CRM modules can be classified into following types:

  1. Entity Module
  2. Extension Module
  3. Language Pack
  4. Bundles

Entity Module

Modules in this category will create entity records in vtiger CRM. The module will provide Create
view, Edit view, Detail view and List view. You will be able to create filters etc.

Entity modules are recommended for cases where a new type of data object, e.g. Timesheet,
needs to be added into the system as part of the new module. These new data objects can be
viewed and managed by administrators and users.

Leads, Contacts, Accounts, Payslip etc… are Entity Modules.

Extension Module

Modules in this category need not follow the general behavior of Entity Module. The records
created by Entity module could be used to provide a extended functionality or the records
creation/editing can be handled in its own way.

Extension modules can be used when add-on functionality is needed, without the need for new
kinds of data objects that users view and manage.

Dashboard, Reports, Portal etc… are Extension Modules.

Language Pack

Language Packs for vtiger CRM are also treated as another kind of module by vtlib.

Bundles

Bundles let you install a set of inter dependent vtlib modules in the specified order.