Trilium natively supports the following formats for both import and export.

- HTML:
  - This is the main format used by Trilium, where standard tags are used to represent basic formatting and layout (e.g. `<strong>`, `<table>`, `<pre>`).
  - Note that HTML is not a standardized format so some more specific features such as admonitions or Internal (reference) links might not be supported by other applications.
- Markdown
  - Most of the formatting is preserved, see Supported syntax.
- OPML (Outliner Interchange Format)
  - Supports both OPML v1.0 for plain text and v2.0 with HTML support.

To import from other applications, see the dedicated pages:

- Evernote
- OneNote