Frequently asked questions
Direct answers to the questions people ask most about OmniPDF.
Is OmniPDF really free?
Yes. Every tool on OmniPDF is free with no account, no watermark, no forced upgrade. Advertising on tool pages covers the hosting cost.
Are my files uploaded to a server?
No. All file processing runs in your browser using JavaScript and WebAssembly. Files are never uploaded to OmniPDF servers. When you close the tab, temporary data is discarded.
Do I need to create an account?
No. OmniPDF requires no account. You can use every tool without signing in.
What browsers are supported?
OmniPDF supports current versions of Chrome, Edge, Firefox, Safari and Samsung Internet on desktop and mobile. Older browsers or browsers with JavaScript disabled cannot run the tools because processing is browser-side.
Can I use OmniPDF offline?
Yes for tools you have already visited. OmniPDF is a Progressive Web App; once a tool is cached, it works without a network. First use of any tool requires a connection to download the required library.
Does OmniPDF work on mobile?
Yes. OmniPDF is built mobile-first and runs on modern Android and iOS browsers. Heavy tools like OCR and compression are slower on mobile; the tool warns you before starting a slow job.
Why is OCR slow?
OCR runs in your browser using WebAssembly, which is 5–10× slower than native code. Expect 10–30 seconds per page on desktop and longer on mobile. Use the max-pages limit to test a sample before processing a long document.
Can I recover a forgotten PDF password?
No. Strong encryption is one-way. OmniPDF cannot recover passwords. Always store your PDF passwords in a password manager.
Is a signature from OmniPDF legally binding?
OmniPDF's signature is an electronic signature image, valid for many everyday contracts under ESIGN, eIDAS and similar laws. For high-value or regulated documents, use a qualified digital signature service such as DocuSign, Adobe Sign or your national eID provider.
How many files can I process at once?
It depends on the tool. Merge PDF supports up to 50 files, JPG to PDF up to 100 images, PDF batch converter up to 20 files. Each tool page shows its limit.
Is there a file size limit?
There is no hard-coded server limit because files are processed locally. The practical limit is your device's available memory. Low-memory phones may fail on files over 40–60 MB. The tool warns you when this might happen.
Do you track which tools I use?
We log anonymised events (tool name and success/failure), never file names or content. This helps us understand which tools are useful and which break.
Which tool should I use to compress a PDF to 100KB?
Use Compress PDF to 100KB. It iterates through progressively stronger compression levels until the target is met, and reports the achieved size honestly if the target is unreachable.
Can I merge a password-protected PDF?
Not directly. Unlock each protected file first with Unlock PDF using its password, then merge the unlocked copies.
Does compression preserve selectable text?
No. Compression tools rasterize pages to achieve size reduction, so text becomes non-selectable in the output. If you need selectable text, use Optimize PDF instead.
What if a tool does not work on my file?
Try opening the file first in PDF Previewer to confirm it is a valid PDF. If preview works but the tool fails, the file may have an unusual structure. Report it to bugs@omni-pdf.pages.dev with the tool name and file description (not the file itself).
Can I add new tools to OmniPDF?
OmniPDF is a closed project. If you have a feature suggestion, email hello@omni-pdf.pages.dev. Features that require server processing will not be added because they break the privacy model.
Where can I report a bug?
Email bugs@omni-pdf.pages.dev with the tool name, your browser, operating system, and a description of what happened. Do not send the file itself — we do not receive files and cannot help with content-level issues.