Compare · OpenSign

Free OpenSign alternative — no upload, no account.

OpenSign is an open-source document-signing platform with a free hosted plan: its pricing page (checked 21 October 2026) lists OpenSign Free as “Free for life” with unlimited e-signatures, and paid plans for advanced features. The difference is architectural: with OpenSign you upload the document to its app (or to your own server, if you self-host) and request signatures there. FreeSign is a browser ceremony that outputs a PAdES-B-T seal with zero document upload and no account.

The structural difference

OpenSign is a full signing platform. Per its FAQ, you upload documents (PDF, DOCX, JPG or PNG), sign them yourself or request signatures from others, and every finalized document gets a completion certificate with access logs; documents are digitally sealed with a P12 certificate. The hosted app at app.opensignlabs.com asks you to log in or create an account, and the source code is on GitHub under the AGPL-3 License so you can self-host it. Because you upload documents to it to sign and route them, the hosted service (or your own server) receives the file.

FreeSign is a cryptographic signing primitive with a thin ceremony shell. The PDF is hashed locally in your browser. A per-user X.509 leaf certificate is issued for that one ceremony from an HSM-backed CA. The CMS PKCS#7 seal is appended to the PDF as an incremental update, and the signed-region hash receives an independent OpenTimestamps proof. FreeSign’s Worker sees the OTP-verified email, your typed name, the OTP challenge, the SHA-256 hash, the public half of your browser ceremony key, the audit hash chain, and a standard request fingerprint — not the PDF.

Side-by-side

Privacy: who can see the PDF?

OpenSign. On the hosted app you upload the document so it can be signed and organized in OpenSign Drive, which means OpenSign processes the file. The trust model is: you accept that OpenSign holds the file and rely on its security and retention controls — or you self-host and take on running the server yourself.

FreeSign. FreeSign cannot read your PDF because we don’t have it. The Worker receives a SHA-256 of the document and a digest of the signature ByteRange. The MCP discovery contract (documentUpload: false) is enforced by a public-contract test. After you download the sealed PDF you can store it wherever you already trust.

Pricing: what “free” means on each side

FreeSign is free for unlimited ceremonies, with no account and no card. Enterprise options (AATL green check, SSO, SMS/KBA verification) are available on request — see pricing; the free product will not be retroactively gated. OpenSign’s pricing page (checked 21 October 2026) lists a free hosted plan with unlimited e-signatures, and its FAQ says you pay only for advanced features such as API access, public links, embedding and advanced validations. Both are genuinely free for basic use. Always re-check before relying on either.

When OpenSign is the right choice

• You want a hosted flow that requests signatures from other people, with signing order, templates and email notifications.
• You want open-source software you can audit and self-host on your own infrastructure.
• You want a document vault (OpenSign Drive) and a completion certificate for every signed document.
• You are comfortable with the hosted service, or your own server, holding the uploaded document.

When FreeSign is the right choice

• The document is confidential and you do not want OpenSign (or any e-sign vendor) to hold it, and you do not want to run a server.
• You want to sign without creating an account.
• You want signing inside your web app (iframe embed) while keeping PDF bytes off FreeSign servers.
• You want an independent OpenTimestamps proof on top of an RFC 3161 timestamp.
• You are fine preparing the PDF elsewhere and only need a verifiable seal.

How to sign a one-off NDA with FreeSign

1. Open the NDA PDF on your machine. Drop it into free-sign.com. The SHA-256 is computed in your browser.
2. Enter your email and full legal name, tick consent. Receive a 6-digit OTP. Type it in.
3. Download the signed PDF — evidence JSON is embedded in the signature’s CMS, so there is one file to keep.
4. Open the signed PDF in Adobe Reader. A yellow ⚠️ trust warning is normally expected (AATL membership), not a sign of a broken signature. Open the Signature Panel and confirm: document not modified, signed by your name.
5. Optional: verify outside Adobe with openssl cms -verify, pyhanko sign validate, and ots verify.

FAQ for switchers