OTG Reader

Review by eFreeware

OTG Reader does one job that Android handles inconsistently: it lets a phone or tablet work with files on a USB flash drive or card reader plugged in through an OTG cable or adapter, including USB Type C connections. The app was updated in August 2026, well after its May 2019 release.

That narrow purpose is the point. If you regularly carry files on a thumb drive and want to open, copy or reorganize them without a computer, this is built for exactly that. If your phone never sees removable storage, there is little here for you.

It is free to install and carries ads, with no in-app purchases offered. Over 100,000 installs and a 4.0 average from 1,560 ratings put it in reasonable standing for a utility of this size, though the ratings alone say nothing about how it behaves on any particular phone and drive.

Built for people who carry files on a stick

The clearest fit is anyone whose work or hobbies leave files on removable media: a photographer pulling shots off a card reader, someone handed a USB drive of documents at a meeting, or a household moving video between a phone and a TV's storage. For those tasks, an app that treats a plugged-in drive as ordinary storage is more useful than a general file manager that may or may not recognize the format.

It also suits people whose drives came from Windows machines. NTFS and exFAT are common on external storage, and support for both is the reason many users look beyond what Android offers by default. The free version's 30MB cap on a single file's line size is the main thing to weigh before you commit to it for large media files.

This is not a tool for tidying up the phone's internal storage. Its focus is external drives attached over OTG, and the file browser exists to work with what is on those drives.

File system support beyond the basics

The headline capability is format coverage. The app reads and writes NTFS volumes, opens exFAT volumes including large ones, and handles FAT32 disks. That matters because a drive formatted on a desktop often arrives in a format Android will not touch on its own, and the developer pitches this compatibility as going further than the platform's built-in support.

There is also a UTF-8 mode you can switch on for file name compatibility, which is the kind of setting that helps when drives contain names in non-Latin scripts or unusual characters. It is a small option, but it addresses a real annoyance for anyone who has seen a folder of garbled names.

The app also loads modules it says are needed for device-specific compatibility. Between that and the format support, the design assumes that phones and drives vary enough that a single fixed approach will not cover everyone.

Connecting, mounting and getting to your files

Connection handling is the other half of the app. Plug in a drive and it is detected and mounted automatically, so you are not hunting through settings to bring it online. A notification tells you when a drive has been mounted, and the app can start itself when a device is connected, which shortens the path from plugging in to seeing files.

The developer also describes an auto-open behavior that takes you straight to the mounted drive, so the file list is in front of you rather than a home screen. When you are finished, a single click unmounts the drive, which is the safe way to disconnect removable storage.

Once a drive is mounted, the file browser shows everything on it, and you can open files with whichever viewer or editor you already use on the phone. A media scanner is triggered on mount so that photos, video and audio on the drive show up in the phone's media library without a separate step. The combination is meant to make an external drive feel like part of the device rather than a separate errand.

What the free download costs you

OTG Reader is free and supported by ads. There are no in-app purchases; anyone who needs more is pointed to a separate full version of the app. That is a straightforward arrangement.

The limit to know about is on file size. In the free version, a single file's line size is capped at 30MB, and the developer advises considering the full version if you need to open anything larger. For text documents, small images and modest audio files, that ceiling is unlikely to come up. For long video recordings or large raw files, it will.

The developer describes this as a limitation of the free version rather than a flaw in the format support, which is a fair way to frame it. You can judge from your own files whether 30MB is generous or restrictive.

Alternatives you might weigh against it

The obvious comparison is whatever file manager already came with your phone. Many handle basic browsing of internal storage perfectly well. What they tend to lack is reliable write access to NTFS and exFAT.

A second option is a desktop or laptop, which remains the most capable way to move large files between a drive and a phone. If your transfers are occasional and you are usually near a computer, the cable-and-computer route costs nothing and avoids the 30MB ceiling entirely.

A third is a cloud service. Sync tools solve the same problem of getting files from one place to another, but they are a poor fit for large video or for drives handed to you by someone else. The appeal of an OTG app is that it works directly with the hardware in your hand.

A practical pick for external drives

OTG Reader is worth installing if your phone is your main computer and USB drives are part of how you move files. The automatic mounting, the mount notification, the auto-open behavior and one-click unmounting all point to an app designed around repeated, quick use rather than occasional fiddling.

The format support is the strongest argument for it. NTFS read and write, exFAT volumes and FAT32 disks cover the drives most people actually own, and the UTF-8 option handles the naming problems that come with them. Add the media scanner on mount and the result is a tool that treats an external drive as ordinary storage.

The free version's 30MB single-file line cap is the one thing to check against your own habits before you rely on it. If your files sit under that size, the free download does the job and the ads are the price of admission. If you routinely open large video or raw captures from a drive, the full version is the route to take.

For everyone else, this is a focused utility rather than a general file manager, and it is best judged on that basis. It exists to make removable storage work on Android, and by the developer's account of its features, that is what it does.