The short answer: Adobe Acrobat Sign is powerful but bundled with paid Acrobat subscriptions. OpenSign™ is a free Adobe Acrobat Sign alternative that signs PDFs online, supports templates and an audit trail, and is open source and self-hostable — no Adobe subscription required.
Why switch from Adobe Acrobat Sign?
- Cost — Acrobat Sign rides on paid Adobe plans.
- Simplicity — you only need to sign PDFs, not a full Acrobat suite.
- Data control — self-hosting keeps documents in-house.
OpenSign vs Adobe Acrobat Sign
| Capability | OpenSign™ | Acrobat Sign |
|---|---|---|
| Free plan | Yes (unlimited self-signing) | Trial / bundled paid |
| Open source | Yes | No |
| Self-hosting | Yes | No |
| PDF signing | Yes | Yes |
| Templates & API | Yes (free) | Paid tiers |
How to sign a PDF without Adobe
- Open OpenSign and upload your PDF.
- Choose Sign Yourself and drag a signature field.
- Draw, type or upload your signature.
- Download the signed PDF and certificate of completion.
For more, see our guide on how to sign a PDF online for free.
Ready to try it? Create a free OpenSign account and start signing documents in minutes — no credit card required. Prefer to run it yourself? OpenSign is 100% open source on GitHub.