Skip to main content

Documentation Index

Fetch the complete documentation index at: https://mintlify.com/tfonteyn/NeverTooManyBooks/llms.txt

Use this file to discover all available pages before exploring further.

NeverTooManyBooks stores everything — your books, bookshelves, cover images, reading styles, and app preferences — in a single, portable ZIP archive (.ntmb or .zip). Creating regular backups protects against data loss from accidental deletion, app reinstalls, or device changes, and the same backup file can be used to migrate your entire collection to a new phone.

​
Backup formats

The primary backup format is a ZIP-based archive that can contain any combination of the following record types:

Books & Bookshelves

All book records stored as JSON, including authors, series, publishers, and bookshelf assignments.

Cover Images

Full-resolution cover art for every book in your collection. Can be large for big libraries.

Preferences

All app settings, custom identifiers, tag definitions, and Calibre custom field definitions.

Styles

Your custom book-list display styles and sort configurations.

Certificates

Named SSL/TLS certificates used for connections to self-hosted Calibre servers or other services.
A backup file is a standard ZIP archive. You can rename it with a .zip extension and inspect its contents with any ZIP tool. Files can be copied freely between Android devices — the format is not device-specific.

​
Creating a backup

1

Open the Backup & Export screen

Tap the navigation menu (hamburger icon) and choose Backup & Export. The screen shows all available export options.
2

Select the archive format

Choose ZIP (backup) from the format dropdown. This is the default and the only format that supports the full set of record types including cover images.
3

Choose what to include

Toggle the checkboxes to select the content you want in the backup:
  • Books — your entire book database (always recommended)
  • Covers — cover image files (can add significant file size for large collections)
  • Preferences — app settings, custom tags, identifiers, and Calibre custom field definitions
  • Styles — your personalised list display styles
  • Certificates — named SSL/TLS certificates for self-hosted server connections
Books, Covers, Preferences, Styles, and Certificates are all included by default when the ZIP format is selected.
4

Choose the export scope

Select one of the two radio buttons:
  • All books — exports every book regardless of when it was last changed
  • New and updated books only — exports only books modified since the last full backup (incremental export)
5

Pick a save location

Tap the upload button (floating action button). Android’s file picker opens. Navigate to your preferred folder and confirm the filename. The app proposes a filename in the format ntmb-YYYY-MM-DD with the appropriate extension.
6

Wait for completion

A progress dialog shows export status. When finished, a summary dialog reports how many books, images, bookshelves, styles, and preferences were written. Files smaller than 5 MB also offer an option to share the backup directly via email.
Save backups to a cloud storage folder (Google Drive, Dropbox, OneDrive, or similar) so they are automatically off-device. This means your collection survives phone loss or factory resets without any extra steps.

​
Restoring from a backup

1

Open the Import screen

Tap the navigation menu and choose Import. The file picker opens immediately so you can select a backup file.
2

Select the backup file

Pick your .ntmb or .zip backup file. The app reads the archive metadata and displays a summary of its contents — creation date, number of books, and number of images — so you can confirm you have the right file before proceeding.
3

Choose what to restore

Depending on what the archive contains, you can selectively enable or disable:
  • Books — restores all book records and related data (authors, series, bookshelves)
  • Covers — restores cover image files
  • Preferences — restores app settings, custom tags, and identifiers
  • Styles — restores your custom display styles
  • Certificates — restores named SSL/TLS certificates for server connections
4

Set the conflict handling strategy

Choose how the app resolves conflicts when a book in the backup already exists in your current database:
OptionBehaviour
New only (Skip)Keeps the existing record; the backup version is ignored
New and updatedReplaces the existing record only if the backup version is newer
All (Overwrite)Always replaces the existing record with the backup version
New and updated is the default and is appropriate for most restore scenarios.
5

Start the restore

Tap the download button (floating action button). A progress dialog tracks the import. When complete, a summary reports books added, books updated, bookshelves created, styles imported, and any rows that could not be parsed.
Restoring cover images for a large collection can be a slow process — each image file is extracted and written individually. Avoid locking your screen or switching away from the app while a cover restore is running, especially over thousands of books.

​
Automatic backup prompts

NeverTooManyBooks tracks how many times the app has been opened since the last full backup. By default the app prompts you to create a backup every 5 app launches after the last recorded full backup date. This prompt appears at startup and is a reminder only — you are not required to back up immediately. Completing a full (non-incremental) ZIP export resets the countdown. Incremental exports do not reset it, since they do not capture the full collection state.

​
Tips for reliable backups

Use cloud storage

Point the file picker at a Google Drive or Dropbox folder. Your backup is immediately synced off-device without any manual transfer step.

Keep multiple backups

Android’s file picker lets you save with a date-stamped filename. Keep at least two or three recent backups so you can roll back further if needed.

Exclude covers for speed

If you back up frequently, uncheck Covers for day-to-day incremental backups and only include them for monthly full backups.

Share across devices

Transfer the .ntmb file to a new device (via cloud storage, email, or USB) and import it to clone your collection exactly, including bookshelves and styles.

Build docs developers (and LLMs) love

Get started for freeTalk to us