The short version
- Choose DocuSign or Acrobat Sign when you need to send a document to several people, control the signing order, send reminders, verify signers' identities, keep a hosted audit trail, or connect signing to other business software.
- Choose OpenSigner when you are the one signing, you want it done in a minute, and you would rather the document never left your device. There is no account, and signing is free with no document limit.
What DocuSign and Acrobat Sign do that OpenSigner doesn't
Both services route documents between people. DocuSign's feature list describes serial, parallel and mixed routing, bulk send, reminders, several signer-authentication options including ID verification, a complete audit trail, and a certificate of completion for every signed envelope (DocuSign eSignature features). Adobe's help pages describe sequential, parallel and hybrid signing orders, with hybrid routing limited to enterprise-tier accounts (Adobe: set up recipient signing order), and an audit report you can download for each agreement (Adobe: download the audit report). Those hosted audit trails record events across every participant, which a tool that never sees your document cannot do.
What OpenSigner does differently
OpenSigner has no server for documents. Your PDF is opened by the browser, pages are drawn by pdf.js, the signed copy is written by pdf-lib, and a SHA-256 seal is computed with the browser's WebCrypto. You get a signed file with a completion certificate and a QR link to a free verifier. After your first visit it also works with the network switched off. The trade-off is clear: because nothing is uploaded, OpenSigner cannot send the file to anyone, chase signers or verify who they are.
Side by side
| OpenSigner | DocuSign eSignature | Adobe Acrobat Sign | |
|---|---|---|---|
| Where the document is processed | In your browser only | On DocuSign's service | On Adobe's service |
| Account needed to sign your own PDF | No | Yes, to send | Yes, to send |
| Send to several signers, set signing order | No (two people can sign on one device with Pro) | Yes: serial, parallel, mixed | Yes: sequential, parallel; hybrid on enterprise tier |
| Signer identity checks | No | Yes, several methods | Multi-factor options, depending on account set-up |
| Audit trail | Completion certificate in the file; Pro adds a per-file audit-trail PDF (no IP addresses, since none are collected) | Hosted audit trail and certificate of completion | Downloadable audit report |
| Tamper evidence | SHA-256 seal, free verifier | PKI tamper seal | See Adobe's documentation |
| Works offline | Yes, after the first visit | Mobile apps can queue offline (per DocuSign) | See Adobe's documentation |
| Price | Free; optional Pro | See DocuSign pricing and Adobe's e-sign plans | |
Competitor details come from the linked official pages, checked on 26 October 2026; features and plans change, so confirm on their sites. DocuSign is a trademark of Docusign, Inc. Adobe and Acrobat Sign are trademarks of Adobe. OpenSigner is not affiliated with either company.