Compare · Adobe Acrobat Sign

The Adobe Sign alternative that never uploads your PDF

If you're already inside the Adobe ecosystem — Reader, Acrobat Pro, Creative Cloud — Acrobat Sign feels like the default. It's a good product. It's also a product where every PDF you sign lives in Adobe Document Cloud. For documents you'd rather not deposit with Adobe, FreeSign is a structurally different option: same PAdES-B-T cryptography, zero document upload.

The structural difference

Adobe Acrobat Sign is the e-signature workflow product layered on top of Adobe's Document Cloud. Per Adobe's published security overview, signed documents are stored on Adobe-operated infrastructure with AES-256 encryption at rest and TLS in transit, SOC 2 / ISO 27001 / HIPAA-eligible plans, with retention configurable by the account owner. Adobe's whole point is to be a managed document service: it routes, stores, audits, integrates with Acrobat Reader's sign-in-place flow, and feeds into the broader Document Cloud product line (Liquid Mode, AI Assistant, etc.). The document goes to Adobe; Adobe handles it; you collect the result.

FreeSign is a cryptographic signing primitive with a workflow shell around it. 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, the OTP challenge, the SHA-256 hash, the public half of your browser ceremony key, the audit hash chain, and a standard request fingerprint (connecting IP, any X-Forwarded-For chain, user-agent, Cloudflare colo/ASN/TLS metadata) on every event. We don't see the PDF.

Both products produce a legally valid PAdES-B-T electronic signature. The cryptographic substrate is interchangeable. The difference is what the vendor holds — and what happens when the vendor stops existing or changes its terms.

Side-by-side

Privacy: who can see the PDF?

Adobe Acrobat Sign. Documents you send through Acrobat Sign are uploaded to and stored on Adobe Document Cloud. Per Adobe's published security overview, encryption at rest (AES-256), TLS in transit, SOC 2 Type II, and ISO 27001 / 27017 / 27018 are in scope; Adobe's Document Cloud business products hold FedRAMP authorizations (Moderate / Tailored, depending on offering — check Adobe's compliance list for the current scope per product). The architectural baseline is that Adobe holds the document. Adobe also publishes AI user guidelines describing what document content is and is not used for. The trust model is: you accept that Adobe holds the document, configure retention and AI participation appropriately, and rely on Adobe's compliance posture and policy enforcement.

FreeSign. FreeSign cannot read your PDF because we don't have it. The Worker receives a SHA-256 of the document and a 32-byte digest of the signature ByteRange — that's it. There is no compliance configuration to get wrong, no AI opt-out to remember, no retention policy to set, because there is no document on our side. The MCP discovery contract (documentUpload: false) is enforced by a public-contract test, so the property can't drift accidentally.

If you're in a regulatory regime that requires the vendor to hold the document for inspection or e-discovery purposes, FreeSign is structurally unsuitable. For most confidential-document use cases — NDAs, term sheets, board resolutions, IP assignments — that requirement doesn't apply, and not uploading the PDF is the correct default.

Verification: what tools accept the signature?

Both Acrobat Sign and FreeSign produce PAdES-B-T signatures. The cryptographic substrate is the same. The differences:

• Adobe Reader trust list. Adobe curates AATL. Adobe-issued and AATL-partner signatures show green; everyone else (FreeSign included) shows yellow ⚠️. This is a commercial trust-list property, not a legal one. See the FAQ explainer.
• OpenTimestamps proof. FreeSign adds an independent OpenTimestamps proof. Acrobat Sign does not. After ~1-2 hours that proof can upgrade to a public block-header attestation — an external timestamp that doesn't depend on Adobe.
• Vendor independence. Adobe Sign's signatures verify in openssl today, but the hosted audit URL and Document Cloud retention are Adobe-operated. FreeSign embeds all trust anchors in the file or on a public chain.

Pricing: how does free actually work?

FreeSign is free today, with no account and no card. Cloudflare Workers + WebCrypto + OpenTimestamps calendars + DigiCert's free TSA tier means the per-signature cost is essentially zero. The HSM CA signature on each leaf certificate costs a fraction of a cent (~$0.000003 per asymmetricSign call). A paid Pro tier is on the roadmap but doesn't exist yet; if it ships, the existing free product won't be retroactively gated behind it.

Adobe's published Acrobat Sign plans are user-seat-based. Acrobat Standard with limited Sign features is ~$12.99/user/month; Acrobat Pro is ~$19.99/user/month; Acrobat Sign Solutions (enterprise) is custom-priced. QES (Article 25(2)) requires partner QTSP add-ons. Free trial available.

When Acrobat Sign is the right choice

• You're already paying for Creative Cloud or Acrobat Pro and the marginal cost of Acrobat Sign is near zero.
• You sign documents from inside Reader / Acrobat regularly and want the in-app signing UX.
• Your counterparty is on Acrobat Sign and won't accept other tools.
• You need an AATL green check as a hard requirement.
• You need Creative Cloud, InDesign, or Sharepoint native integration.
• You need QES (Article 25(2)) for one of the narrow EU public-authority use cases.

When FreeSign is the right choice

• The document is confidential and you'd rather Adobe not hold it.
• You don't want a Creative Cloud or Acrobat subscription just to sign a PDF.
• You want independent OpenTimestamps proof in addition to a DigiCert TSA.
• You want verification that doesn't depend on Adobe existing in 10 years.
• You're a developer or automation user who'd rather call a REST or MCP endpoint than drive Acrobat's UI.
• You're cost-sensitive and the in-Reader UX isn't a hard requirement.

How to migrate a one-off NDA flow to 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. The browser captures the ceremony locally, the server witnesses, the seal is assembled, and the OpenTimestamps proof is submitted.
4. Download the signed PDF — the evidence JSON is embedded inside it (in the signature's CMS), so there is one file to keep.
5. Open the signed PDF in Adobe Reader. Reader will show yellow ⚠️ — that's the AATL trust warning, not a verdict on document integrity. Click “Signature Panel”: Document has not been modified, Signed by <your name>, Signature is valid. Note: after the leaf cert's expiry (default 10 years), Reader may show a different message even though the underlying CMS, the DigiCert RFC 3161 timestamp, and the OpenTimestamps proof still attest the original moment cryptographically — the colour Reader paints isn't the cryptographic answer.
6. Optional: verify outside Adobe with openssl cms -verify, pyhanko sign validate, and ots verify.

FAQ for switchers