OpenSign review

OpenSign is open-source software for signing PDF documents electronically. Its homepage advertises a free plan with unlimited e-signatures, collaboration, completion certificates and document storage in OpenSign Drive. The free plan also includes unlimited guest signers, according to the pricing page; seat limits are not published.

The basic pitch is straightforward: send a document for signatures, invite other people to sign, and keep the completed document and its certificate in the Drive vault. OpenSign says certificates include access logs. The published product information does not specify storage limits, document-retention rules or the technical details of how signatures are verified, so those are worth checking before using it for sensitive or regulated workflows.

OpenSign has paid plans for premium sending features. The pricing page lists OpenSign Professional at $29.99 per month with monthly billing, or $9.99 per month when billed annually. Teams is $39.99 per user per month monthly, or $19.99 per user per month annually. Those paid tiers have credit caps; the free plan’s headline benefit is unlimited basic signing.

The main advantage is unusually clear: the OpenSign Free plan is listed as free for life, with unlimited e-signatures and unlimited guest signers. That makes it a plausible fit for individuals who need basic signing without paying per signature. OpenSign also advertises collaboration, completion certificates with access logs, and document storage in its Drive vault, so the offer is more than a bare signing form.

The pricing page separates basic signing from premium sending rather than charging for every signature. For people who need the latter, the Professional plan costs $29.99 monthly or $9.99 per month on annual billing. It includes 100 premium credits per month with monthly billing, or up to 240 credits per year on annual billing; annual bulk sending is capped at 240 documents. The pricing page says one credit covers listed premium sending methods for up to 10 signers.

Teams includes 100 credits or API signatures monthly, or up to 500 per year on annual billing. Its bulk-send allowance is up to 100 documents monthly or 500 annually. Those published caps give buyers a basis for comparing likely usage before switching.

Unlimited signatures do not mean unlimited premium sending. Professional’s annual billing includes up to 240 credits per year and up to 240 bulk-sent documents annually; monthly billing includes 100 premium credits each month. Teams is capped at 100 credits or API signatures per month on monthly billing, or up to 500 per year annually. Teams also charges per user, and the pricing page does not publish seat caps. Free-plan seat limits are also not published, while Enterprise pricing and usage limits are not published.

The open-source model raises a separate question about product continuity and trust. One Reddit thread discussed a fork removing paid-plan restrictions, and commenters debated the project’s AGPLv3 licensing and the rights that come with it. That discussion is not proof that OpenSign is insecure or unsupported, but it does show a dispute around how the project funds development.

Another Reddit thread raised a concern common to self-hosted signing tools: whether a service operator with access to the server can alter signed documents or signature data. The published material does not provide enough technical detail to settle that concern. Buyers who need independent verification should ask OpenSign how its certificates and document integrity are protected.

OpenSign Free costs $0 for life and lists unlimited e-signatures and unlimited guest signers. Seat limits are not published. The lowest paid price is Professional at $9.99 per month when billed annually; monthly billing is $29.99. That annual price is a billing equivalent, not the month-to-month rate.

Professional includes 100 premium credits per month on monthly billing, or up to 240 credits per year on annual billing. Annual bulk sending is capped at 240 documents. One credit covers the listed premium sending methods for up to 10 signers.

Teams costs $39.99 per user per month on monthly billing or $19.99 per user per month billed annually. Its allowance is 100 credits/API signatures monthly or up to 500 annually, with bulk sending capped at 100 documents monthly or 500 annually. Seat caps are not published, so costs can grow with users. Enterprise pricing is custom, with usage limits unpublished. No add-ons are listed. Free signing is unlimited; premium sending is capped, so check your billing term and expected volume before switching.

OpenSign is described as open source, but that alone does not confirm how easily you can move documents in or out. The published product details name the OpenSign Drive vault and completion certificates with access logs, but do not publish bulk-export tools, import options, or migration support. Before switching, ask whether you can export PDFs, certificates, access logs, signer history, and stored files in bulk, and whether your current documents can be imported with their audit records intact.

We were not given Reddit posts or comments for this review, so we can't credibly report why Reddit users leave. The documented reasons to check fit are clearer: premium sending has credit and bulk-send caps, seat limits are unpublished, and the provided verdict flags workflows needing independent signature verification as a poor fit. Test your exit path and confirm those limits with OpenSign before moving sensitive or high-volume work.