Is the file really not uploaded?

It is not. You can check in your browser's network tab: requests for ads, analytics and fonts do appear, but no file is among them. A tool you have used once keeps working with the network off, so the clearest test is to switch to airplane mode and try it again.

Nothing. Running costs are covered by ads.

How large a file can I use?

It depends on your device's memory. Very large files such as long videos can fail on a phone; when a limit is hit, the tool says so. Try a desktop browser in that case.

Do these work on a phone?

Yes. Tools that handle images or video depend on the device's performance, so large files are more stable on a computer.

Can I ask for a tool to be added?

Yes — use the contact link in the footer. The one requirement is that the processing can run entirely in the browser.

Whatever you need to do,
right here in the browser.

StemStudio is a platform of web tools with nothing to install. Pick a file and start working — it never leaves your device.

Drop a file hereor click to choose one

Nothing to install
Processed in your browser
Works anywhere, any time

Supported formats

Audio: MP3, WAV, FLAC, M4A, AAC, OGG, ...
Images: PNG, JPG, JPEG, WEBP, GIF, HEIC, ...
Video: MP4, MOV, WEBM, MKV, AVI, ...
Documents: PDF, TXT, CSV, JSON, ...

64+ToolsFor a wide range of jobs
Private by designNothing is uploaded
FastRuns instantly in your browser
Any devicePhone, tablet or desktop

Why in-browser processing

Files never leave your device: All processing happens on your device, so files are never sent to or stored on a server. Work documents and files containing personal information are fine to use.
Little waiting: There is no upload or download, so processing starts right away. A tool you have used once stays on your device, so it still opens and works with no network at all.
No account, no usage caps: No sign-up is required, and there is no limit on file counts or daily use.

Questions

Is the file really not uploaded?: It is not. You can check in your browser's network tab: requests for ads, analytics and fonts do appear, but no file is among them. A tool you have used once keeps working with the network off, so the clearest test is to switch to airplane mode and try it again.
What does it cost?: Nothing. Running costs are covered by ads.
How large a file can I use?: It depends on your device's memory. Very large files such as long videos can fail on a phone; when a limit is hit, the tool says so. Try a desktop browser in that case.
Do these work on a phone?: Yes. Tools that handle images or video depend on the device's performance, so large files are more stable on a computer.
Can I ask for a tool to be added?: Yes — use the contact link in the footer. The one requirement is that the processing can run entirely in the browser.

Whatever you need to do,
right here in the browser.

Popular

Find every tool

Supported formats

Why in-browser processing

Questions

Whatever you need to do,right here in the browser.

Drop a file to see what you can do with it

Popular

Find every tool

Supported formats

Why in-browser processing

Questions

Whatever you need to do,
right here in the browser.