DEVONthink stores a large number of metadata fields internally when importing documents from the file system, e.g., from PDF, RTF, MP3, EXIF/IPTC, HTML, and email messages as well as from all files that deliver metadata through the Spotlight metadata importer. Here's a partial list of theoretically supported fields:

## File Metadata

General Metadata:

- Title
- Headline
- Subject
- Creator
- Producer
- Editor
- Contributor

PDF Metadata:

- Author
- Title
- Subject
- URL
- Keywords

RTF Metadata:

- Author
- Title
- Comment
- Subject
- URL
- Keywords
- Organization
- Copyright

Email Metadata:

- Authors
- Author email addresses
- Recipients
- Recipient email addresses
- Email addresses

Media and Publication Metadata:

- Album
- Composer
- Contributors
- Publishers
- Editors
- Organizations

HTML Metadata:

- title
- description
- author
- comment
- subject
- organization
- keywords
- publisher
- email
- copyright
- generator
- dc.title
- dc.creator
- dc.subject
- dc.description
- dc.rights
- dc.contributor
- dc.keywords
- dc.publisher
- og:title
- og:description
- geo.position

Pro

## Custom Metadata

Another powerful feature of DEVONthink is custom metadata fields. Specified in the Settings > Data, you can define fields that are meaningful to you, your company, your research group, or even your family!

When you create a custom metadata field, you give it a name. DEVONthink uses this name to create an identifier for use in automated processes. This identifier is created automatically and cannot be changed.

Data Types: When you define a custom field, you choose a data type for it. So what's a "data type"? It's simply a type of value; like "a" is a character and "42" is a (the!) number. The following data types are supported, including any interface items associated with them, e.g., checkboxes or dropdown menus:

- Boolean: This is a true or false value. Displayed as a checkbox.
- Countries: A dropdown menu providing a list of country names. Supports an Undefined state
- Languages: A dropdown menu providing a list of languages. Supports an Undefined state
- Integer: A whole number, e.g., with no fractional part, like 17.
- Decimal Number: A fractional number, represented with a decimal point.
- Date: Can be specified as Date & Time or Date.
- Identifier: Any alphanumeric value, specified as needed, e.g., a customer or patient number.
- Single-line Text: A dropdown providing a list of terms you defined for the field in the Data preferences. You can also type in a new value.
- Multi-line Text: Enter a small paragraph of text. Line breaks can be typed by pressing Option-Return.
- Rich Text: Same as Multi-line text but supports basic formatting, e.g., bold or italic text.
- Set: Similar to the Single-line text, this shows a dropdown with values pre-defined for the field in the Data preferences. However, new values can't be entered outside the preferences. Supports an Undefined state.
- URL: Accepts any valid URL, including filesystem URLs.
- Link: A special dropdown that allows you to choose an item in your databases. a link for the chosen item is used.

Note there are metadata attributes that support an Undefined option: Countries, Languages, and Sets. This can be used anywhere custom metadata is displayed, e.g., in an item list column or the Data inspector. You can search for this by leaving the term empty, e.g., `mdcountry=` is equal to "The Country attribute is Undefined."

Note: The Countries and Languages lists are lengthy, but not necessarily exhaustive. For Multi-line Text and Rich Text, only one line will be displayed in its column in the item list.

Predefined Custom Metadata: In Settings > Data, we have provided some custom metadata fields to get you started. These are ready to use and explore and serve as great examples of the data types discussed above:

- Date
- Company
- Author
- Abstract
- Status
- Serial Number
- ISSN/ISBN
- Digital Object Identifier (DOI)
- PubMed ID
- PMC ID
- Barcode
- Format
- Category
- Subcategory
- Genre
- Country
- Language
- Price
- Tax
- Tip
- Decimal