# `boolean` > The boolean type matches only two special values: `true` and `false`. Note that values that evaluate to `true` or `false`, such as 1 and 0, are not accepted by the schema. ## Visuals The following schema describes a boolean. ```yaml type: boolean description: True if it is active example: true ``` The following image shows the boolean schema. ![schema boolean](/assets/schema-boolean.c436d3e8de26a35662f038335e6b4438ad46bdde4319d14d65fff3dd1e292486.6f948c6e.png) ## Types - SchemaProperties ```ts const SchemaProperties: NodeType = { properties: {}, additionalProperties: 'Schema', }; ```