Legally binding e-signatures. Free to start — no card, no envelope games. Sign the sample on the right to see exactly what your recipients get.
Drag in a PDF. We keep the layout pixel-perfect — no reflow, no surprises.
Drop signature and date fields. Every signer gets their own colour, start to finish.
Each party signs. We PAdES-seal the final PDF so it verifies anywhere — forever.
No badge walls, no logo strips. The audit trail and the sealed certificate are the product — so here they are.
"Our clients used to ask if the signature was 'really legal.' Now they just see the seal and the trail. The question stopped."
"The free tier actually says what you get. Three docs a month, printed on the card. After DocuSign's envelope math, that felt radical."
"I dropped a sealed PDF into Adobe Reader and it verified clean. That's the whole pitch — it holds up outside their walls."
MostlySign isn’t open yet — sign-in and sign-up are closed while we finish building it. Leave your email and we’ll let you know the moment it’s ready.
Notify me at launch