Discover why FreeConversion is the best free and private alternative to PDFfiller for merging your PDFs.
Select multiple files to join them into one.
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🔒 100% Secure • Local Processing
Last updated : May 14, 2026
Specialized in forms and signatures (eSign)
Elaborate enterprise workflows
Salesforce and CRM integrations
$20/month for Basic — pricey for merging
Airslate (Boston, USA)
Account required from upload step
Form-centric — merge is secondary
Merge is our direct service, not a side feature
No $20/month subscription
No upload, no account
PDFfiller (https://www.pdffiller.com) is a popular tool, but it has significant limitations. The main difference with FreeConversion is privacy: unlike PDFfiller which sends your files to remote servers, FreeConversion processes everything locally in your browser using WebAssembly technology.
This means your sensitive documents (contracts, resumes, bank statements) never leave your computer. Additionally, FreeConversion is 100% free with no file limits, no registration, and no ads.
Absolutely! FreeConversion is perfect for professional documents. Since all processing happens locally in your browser, your confidential documents remain 100% private.
FreeConversion handles large files directly in your browser. The limit depends mainly on your device's memory, but files up to 100MB are processed without issues.
The free and private alternative to PDFfiller. No limits, no registration.
Compress my PDFs for free →