json

The json widget takes the value of a json field and prints it as formatted text. The whole component is a few lines long: it reads this.props.record.data[this.props.name], passes it through the shared formatJson formatter, and renders the result.

There is no input element. The user can read the value and copy it, and that is all. If you need an editable JSON blob, this is the wrong widget.

It declares supportedTypes: ["json"] and no supportedOptions key at all. That is not an oversight in our reading: the descriptor object in the source has exactly three keys, component, displayName and supportedTypes.

If your team can see a raw JSON blob on a form, something technical is being surfaced deliberately: a stored API response, a computed structure, a debugging aid. The useful thing to know is that nobody can break it by typing in the wrong place, because there is nothing to type into.

The flip side is that a json field is not a reporting field. It does not group, it does not filter usefully, and it does not export in a shape a spreadsheet will like. If people are reading data out of a JSON blob by eye, that data wants to become real fields.

You rarely need to write this at all. A json field with no widget attribute already renders through this widget:

<field name="payload"/>  <!-- a json field: the json widget is applied automatically -->

Writing it explicitly changes nothing, but is harmless and self-documenting:

<field name="payload" widget="json"/>

We counted every widget="json" attribute in Odoo 19 Community and Enterprise. The answer is zero. That looks like a dead widget until you read how Odoo picks a component.

In addons/web/static/src/views/fields/field.js, getFieldFromRegistry ends with this line:

return findInRegistry(fieldType) || { component: DefaultField };

When a field carries no widget attribute, Odoo looks up the fields registry using the field type name as the key. The json widget is registered under the key json, and the field type is also called json, so every json field in every view resolves to this widget without anyone writing it down.

The same function holds a second detail worth knowing on any widget page. When you do pass a widget whose supportedTypes does not include the field's type, Odoo does not raise an error. It logs a console warning and renders the widget anyway:

console.warn(`The widget: ${widget} don't support the type ${fieldType}`);

So a mismatched widget fails quietly in the browser console rather than loudly on screen. If a field looks wrong and the server logs are clean, open the browser console before anything else.

Nothing changes. We diffed the 20.0 branch against 19.0 and the json registration is identical: same component, same supportedTypes, still no options.

That is worth stating plainly because a lot of the Odoo 20 widget release is not stable. Roughly 48 widgets changed options or types between the two branches. This one did not.