Odoo's user interface, its front end, is built with its own component framework, called OWL. This piece is about building an OWL component in Odoo.
Odoo's front end and OWL
Odoo's user interface, the front end, the part of Odoo the user genuinely sees and interacts with in their browser, is built with a component framework, Odoo's own, called OWL. Front-end functionality in Odoo is built as components in that framework. So a developer who builds front-end functionality, who builds something in the part of Odoo the user interacts with, builds an OWL component.
What an OWL component is
An OWL component is a piece of Odoo's front end built in the OWL framework: a component, in the sense the framework uses, a defined piece of the user interface, with its presentation and its behaviour. Building an OWL component is building such a piece of front-end functionality, defining what it presents to the user and how it behaves, within the OWL framework.
When a developer builds OWL components
A developer builds OWL components when the development genuinely involves the front end, building something in the part of Odoo the user directly interacts with. A great deal of Odoo development is on the back-end side, the models, the business logic, where the front end is handled by views defined in XML and does not need OWL component development. Building an OWL component is for when the development genuinely needs custom front-end functionality, a custom piece of the interface, custom interactive behaviour, that goes beyond what the standard view definitions provide. So OWL component development is the front-end side of Odoo development, used when the front end genuinely needs custom work.
Building OWL components is genuine front-end development
An honest note. Building OWL components is genuine front-end development: it works with Odoo's front-end framework, and it is a genuine technical skill, distinct from the back-end side of Odoo development. A developer building OWL components needs to genuinely work with the OWL framework, the way it builds the front end. It should be done, like all Odoo development, the Odoo way, working with the framework as it is meant to be worked with. Building OWL components well is genuine front-end development done within Odoo's front-end framework.
Use OWL component development where the front end genuinely needs it
The practical guidance is that a developer should build OWL components where the development genuinely needs custom front-end functionality, and should not over-reach into front-end development where it is not needed. A great deal of Odoo functionality is built without custom OWL component development, with the standard views. Custom OWL component development is for the genuine cases where the front end needs custom work, and it should be used for those, working with the OWL framework as Odoo intends.
The takeaway
Building an OWL component in Odoo is front-end development: Odoo's user interface is built with its own component framework, OWL, and front-end functionality is built as OWL components, defined pieces of the interface with their presentation and behaviour. A developer builds OWL components when the development genuinely needs custom front-end functionality, beyond what standard view definitions provide. It is genuine front-end development, done within Odoo's front-end framework, the Odoo way, and used where the front end genuinely needs custom work. For how we approach Odoo, see our ERP practice.