┌─ FILE ANALYSIS ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── ┐
│ DEVELOPER : Mobipocket SA (Amazon)
│ CATEGORY : Document
│ MIME TYPE : application/x-mobipocket-ebook
│ MAGIC BYTES : 424F4F4B4D4F4249
└ ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── ┘
What is a MOBI file?
MOBI is an eBook format originally created by Mobipocket SA, later acquired by Amazon. Based on the Open eBook standard, MOBI files support DRM, bookmarks, annotations, and JavaScript. While Amazon has transitioned to KFX and AZW3 formats for newer Kindles, MOBI remains widely used for sideloading eBooks.
How to open MOBI files
- Kindle (devices and apps) — Native support
- Calibre (Windows, macOS, Linux) — Free, can convert
- FBReader (Windows, Linux, Android) — Free
- Sumatra PDF (Windows) — Lightweight reader
Technical specifications
| Property | Value |
|---|---|
| Base Format | Open eBook (OEB) |
| Compression | PalmDOC or HUFF/CDIC |
| DRM | Mobipocket DRM |
| Image Support | JPEG, GIF |
| Successor | AZW3 / KFX (Kindle Format) |
Common use cases
- Kindle sideloading: Manually adding books to Kindle devices.
- Legacy eBooks: Older digital book collections.
- Self-publishing: Distribution to Kindle readers.
- Format conversion: Source format for Calibre conversions.