Back up and image your Android phone from Windows
Quasar walks you through every step of a backup over ADB, creates full partition images you can restore, compares compression formats on your own data, and uploads encrypted copies to the cloud.
Get Quasar Try it freeWhat it does
Guided backup
Step-by-step help connecting your phone, enabling USB debugging and approving the backup on-screen.
Full phone images
Partition-level images with checksums and a manifest. Restore from recovery or with root, with a read-back check after every write.
Compression Lab
Compare Zstandard, Gzip, Bzip2, XZ, ZIP and 7-Zip on size and speed, then use the winner for backups and images.
Encrypted cloud upload
Encrypt on your PC before anything leaves it. Upload to S3-compatible storage, a local folder and more.
Your data stays yours
No account and no tracking. Backups go where you tell them to, and only you hold the passphrase.
Made for Windows
A native desktop app that runs without an installer: unzip it and launch.
Pricing
Free
- 6 backups per month
- 2 GB cloud upload per month
- Every format and tool
Payments are handled by Gumroad. After purchase you receive a download and a license key. Open the License page in Quasar, paste the key and click Activate.
Quasar for Android
Back up files and folders on the phone with Zstandard, TAR+Gzip/Bzip2/XZ, ZIP or 7-Zip, optional XChaCha20-Poly1305 encryption, a built-in Compression Lab and the same Free / Supporter / Pro license keys as Windows. Download the APK, allow installs from unknown sources, and open it. The Windows app can also install it over ADB.
Getting started
- Download the zip from your Gumroad receipt and unzip it anywhere.
- Run Quasar.exe and follow the Guided backup page.
- Activate your license on the License page (optional for the Free plan).
Compression formats
| Format | Fast | Balanced | Max | Best for | Backups | Phone images |
|---|---|---|---|---|---|---|
| Zstandard | L3 | L12 | L19 | Best ratio-to-speed; the recommended default | Yes | Yes |
| Zstandard Ultra | - | - | L22 | Smallest Zstandard output; slowest | Yes | Yes |
| TAR + Gzip | L1 | L6 | L9 | Universal compatibility | Yes | Yes |
| TAR + Bzip2 | L1 | L5 | L9 | Good ratio, slow | Yes | Yes |
| TAR + XZ | L1 | L6 | L9 | Very small, very slow | Yes | Yes |
| ZIP (Deflate) | L1 | L6 | L9 | Opens everywhere on Windows | Yes | Yes |
| 7-Zip (LZMA2) | L1 | L5 | L9 | Strong ratio; needs 7-Zip to open | Yes | No |
| No compression | Stored as-is | Fastest, largest | Yes | Yes | ||
Not sure which to pick? The Compression Lab runs the formats you choose on your own data, compares size, compression speed and decompression speed, and a single click applies the winner to your backups and phone images. 7-Zip is not offered for phone images because the format can't be written as a continuous stream from the phone.