Firmalo lets you sign PDF documents online for free, without creating an account and without adding a watermark. The key difference is privacy: files are processed locally in the browser, so the PDF never leaves your device. It works on desktop and mobile, supports Spanish and Portuguese, and is built for fast everyday PDF signing rather than complex contract workflows.

I built Firmalo because signing a simple PDF online is still weirdly annoying: many tools ask for registration, add watermarks, push paid plans, or upload your document to a server. The goal was to make the fastest possible PDF signing flow for everyday use: - open the site - upload a PDF - add your signature - download the signed file No signup, no watermark, and the file stays in your browser instead of being uploaded. I started with Spanish and Portuguese because PDF signing is a common task across LATAM and Brazil, and many existing tools either feel too heavy or are not localized well enough. Firmalo is not trying to replace full e-signature platforms like DocuSign for certified signatures or legal workflows. It is for the simple case: “I just need to sign this PDF now.”

How does signing actually work in the browser without the PDF being uploaded somewhere, and is the signature still legally binding for things like contracts or tax forms?

Firmalo

Sign PDFs online free, no signup or watermark

Sign PDFs online free, no signup or watermark