--- title: "book:release_date · Meta Tag · zhead" canonical_url: "https://zhead.dev/meta/book-release-date" last_updated: "2026-08-10T16:29:03.041Z" meta: description: "Records when a book was released. Open Graph defines the value as an ISO 8601 datetime." "og:description": "Records when a book was released. Open Graph defines the value as an ISO 8601 datetime." "og:title": "book:release_date · Meta Tag · zhead" --- Open Graph metadata # book:release\_date Records when a book was released. Open Graph defines the value as an ISO 8601 datetime. ## Code examples Good example ``` ``` An ISO 8601 calendar date when no exact release time is needed. Good example ``` ``` A release datetime with an explicit UTC offset. Avoid this example ``` ``` Readable to people, but outside the ISO 8601 syntax Open Graph specifies. Avoid this example ``` ``` The day and month order is ambiguous. ## Recommendations - 01 Use ISO 8601 Format Use a complete ISO 8601 value that matches the known precision of the release. - 02 Include Timezone When you include a time, add a UTC marker or offset so the instant is unambiguous. ## Related documentation - [Open Graph protocol](https://ogp.me/) ## Related meta tags ### [book:author](https://zhead.dev/meta/book-author) property Links a book to an author profile. The value is a URL, and you can repeat the property for multiple authors. ``` ``` Points to the author’s profile page. ### [book:isbn](https://zhead.dev/meta/book-isbn) property Provides the book’s International Standard Book Number as a string. ``` ``` A valid ISBN-13 written without display separators. ### [book:release\_date](https://zhead.dev/meta/book-release-date) property Records when a book was released. Open Graph defines the value as an ISO 8601 datetime. ``` ``` An ISO 8601 calendar date when no exact release time is needed. ### [book:tag](https://zhead.dev/meta/book-tag) property Adds a tag word or phrase associated with a book. Repeat the property to provide more than one tag. ``` ``` A clear genre for the book.