# Notes

| environment variable                    | default | example                         | description                                                                                                                                                                                       |
|-----------------------------------------|---------|---------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| `HD_NOTE_FORBIDDEN_ALIASES`             | -       | `notAllowed, alsoNotAllowed`    | A list of note ids (separated by `,`), that are not allowed to be created or requested by anyone. All aliases in this list are converted to lowercase, so you don't need to repeat yourself here. |
| `HD_NOTE_MAX_LENGTH`                    | 100000  |                                 | The maximum length of any one document. Changes to this will impact performance for your users.                                                                                                   |
| `HD_NOTE_PERMISSIONS_MAX_GUEST_LEVEL`   | `write` | `deny`, `read`, `write`, `full` | Defines the maximum access level for guest users to the instance. This value needs to be at least as "high" as `HD_NOTE_PERMISSIONS_DEFAULT_EVERYONE`.                                            |
| `HD_NOTE_PERMISSIONS_DEFAULT_LOGGED_IN` | `write` | `none`, `read`, `write`         | The default permission for the "logged-in" group that is set on new notes.                                                                                                                        |
| `HD_NOTE_PERMISSIONS_DEFAULT_EVERYONE`  | `read`  | `none`, `read`, `write`         | The default permission for the "everyone" group (logged-in & guest users), that is set on new notes created by logged-in users. Notes created by guests always set this to "write".               |
| `HD_NOTE_PERSIST_INTERVAL`              | 10      | `0`, `5`, `10`, `20`            | The time interval in **minutes** for the periodic note revision creation during realtime editing. `0` deactivates the periodic note revision creation.                                            |
| `HD_NOTE_REVISION_RETENTION_DAYS`       | 0       |                                 | The number of days a revision should be kept. If the config option is not set or set to 0, all revisions will be kept forever.                                                                    |
