How to sideload ebooks to Kindle, Kobo, Boox, and reMarkable

Every modern e-reader will accept files you didn't buy from its store. The path is different for each one. This guide walks through all four major brands plus the Kindle Scribe specifically, including which format each device actually likes.

Published 2026-05-26 · All guides

What "sideloading" means

Sideloading is just putting files on the device through means other than its built-in store. A USB cable, a wireless transfer service, or a manufacturer's desktop app. The files can be your own writing, a public-domain Project Gutenberg classic, a DRM-free purchase from Standard Ebooks or Tor, a PDF you've been emailed, or an EPUB a friend made. Sideloading is fully supported on every device covered here. None of this involves jailbreaking, sketchy firmware, or anything that voids a warranty.

The one universal rule: pick the right format before you transfer. EPUB is the open standard and works almost everywhere. PDF works everywhere but reads badly on small e-ink screens because the text can't reflow. Amazon's older proprietary formats (MOBI, AZW3) are now phased out — Amazon's own Send to Kindle service prefers EPUB as of 2022.

Kindle (Paperwhite, Oasis, Basic, Colorsoft)

Amazon supports two reliable methods. The first is "Send to Kindle," a free service that converts and delivers files wirelessly. You can use it from a browser at send-to-kindle.amazon.com, from a dedicated desktop app for Windows and macOS, or by emailing the file to your personalized Kindle email address (find it under Manage Your Content and Devices → Preferences → Personal Document Settings).

Send to Kindle accepts EPUB, PDF, DOC, DOCX, RTF, HTML, TXT, and several image formats. EPUBs are converted server-side to Amazon's KF8 format on the way to your device. PDFs are delivered as-is, which is rarely what you want on a small screen — convert PDFs to EPUB before sending using PDF to EPUB.

The second method is a USB cable. Plug the Kindle into a computer, mount it as a drive, and copy files into the documents folder. The device picks them up after you eject and disconnect. USB is the only method that doesn't go through Amazon's servers, which matters if the document is sensitive.

Kindle Scribe

The Scribe is a Kindle with a 10.2-inch screen and a pen. Sideloading works the same way as on a standard Kindle — Send to Kindle or USB. What's different is the screen real estate and that you'll want to annotate. Two specific tips:

Convert PDFs to EPUB whenever possible before sending. PDFs sent to the Scribe display as fixed pages with no reflow, which makes long-form reading worse than on a tablet, and the annotation tools work better on EPUB. The PDF for Kindle Scribe converter handles this with margins sized for the device.
For your own handwritten notes, the Scribe exports back to PDF over Send to Kindle, which sends them to your linked email. The notebooks aren't sideloadable back to other devices in any other format.

Kobo (Clara, Libra, Sage, Elipsa, Forma)

Kobo is the easiest device to sideload to. The OS reads EPUB natively, so there's no conversion step. There are three ways in:

USB cable. Plug into a computer, mount the device as a drive, and drop EPUB or PDF files into the root of the drive or any folder inside. Kobo scans on disconnect and adds new files to your library automatically.
Dropbox or Google Drive sync. Newer Kobos (Sage, Libra Colour, Elipsa, Clara BW) have built-in cloud sync. Drop a file into the linked folder on your computer and it appears on the device when it next syncs.
Pocket and OverDrive. Strictly speaking not sideloading — these are read-it-later and library services baked into the OS — but they cover most of what people use sideloading for in practice.

Kobo handles EPUB 3 features (footnotes, images, CSS) better than Kindle, so prefer EPUB over PDF where you have the choice. The PDF for Kobo converter is the one to use when you have a PDF you want to read.

Boox (Note Air, Tab Ultra, Palma, Go)

Boox runs Android under the hood, which means it's the most flexible e-reader for sideloading and the most fiddly. The official reader is called NeoReader, but you can also install KOReader, Moon+ Reader, Google Play Books, or the Kindle Android app side-by-side. Sideload methods:

USB cable. Mount as a drive; drop files into Books or anywhere on internal storage.
BooxDrop. Boox's built-in feature lets you drop files via a web browser on the same Wi-Fi network. Open the address shown on the device and drag files in.
OneDrive, Dropbox, or any cloud app from Google Play. Install the app, log in, and download files like you would on a phone.

EPUB and PDF both work well thanks to the screen size. For long-form text, EPUB is still better. The PDF for Boox converter sizes pages for the Air, Tab Ultra, and Palma specifically.

reMarkable (rM2 and Paper Pro)

reMarkable is the most locked-down of the four major brands. Sideloading goes through three channels:

The desktop and mobile apps. Install the reMarkable app, drag files into the "My files" pane, and they sync to the tablet when it next connects to Wi-Fi.
The web upload at my.remarkable.com. Browser-based, same effect as the desktop app.
USB web interface. Plug in via USB, enable USB Web Interface in the device settings (Storage section), and open http://10.11.99.1 in any browser on the same computer. Drag files into the page that loads. This is the only method that doesn't touch reMarkable's servers.

reMarkable accepts EPUB and PDF. Annotations work on both, but PDF gets the better pen behavior. The PDF for reMarkable converter sizes pages with extra margin space for handwritten notes.

Picking a format before you transfer

Three quick rules:

If the source is a reflowable text (a novel, an article, a long blog post), use EPUB. Every device handles it, and the text resizes to the device.
If the source has a layout that matters (a textbook, a sheet music page, a magazine, an academic paper), keep it as PDF. EPUB can't preserve fixed layouts well.
If the source is a PDF that you'd rather read as text (a novel scanned into a PDF, a manuscript), convert it to EPUB first.

What to do about DRM

Sideloading does not bypass DRM, and stripping DRM from purchased ebooks is a copyright violation in most countries even when the file is for personal use. The safe rule: only sideload files you own (your own writing, public-domain books, DRM-free purchases). Sources for legitimate DRM-free EPUBs include Standard Ebooks (free, public-domain classics with modern typography), Project Gutenberg (free, the original public-domain archive), Tor.com, Smashwords, the Humble Bundle ebook bundles, and direct publisher sites for many science and tech books.

Where to go from here

If you have a specific file you're trying to get onto a specific reader, the device-targeted converters do the format conversion and sizing in one step:

For the underlying format work, see EPUB to PDF and PDF to EPUB, or the explainer What is an EPUB? for background.