What is an e-signature audit trail? The Certificate of Completion, explained
The audit trail is what makes an e-signed document defensible: who signed, when, from where — sealed against tampering. Here's what a Certificate of Completion contains.
When people compare e-signature tools they look at price, templates, and how the signing screen feels. The feature that actually earns its keep is the one nobody looks at until years later: the audit trail. It's the difference between "here's a PDF with a squiggle on it" and "here's evidence of exactly who agreed to what, when, from where." Here's what an audit trail is, what a Certificate of Completion contains, and what to check in whatever tool you use.
What the audit trail records
From the moment you hit send, the tool logs every event in the document's life:
- Sent — when the request went out, and to which email address.
- Viewed — when each signer opened the document, with timestamp and IP address.
- Signed — the moment each signer completed their fields, again with time and IP.
- Completed — when the final signer finished and the document was sealed.
Each entry is tied to a specific signer — the email the link was sent to, the device that opened it. On Signed this log builds automatically on every document; you watch the same events as live statuses on your dashboard (the flow is in Sending & signing).
The Certificate of Completion
When the last signature lands, the audit trail is compiled into a Certificate of Completion — a summary document attached to the final PDF listing every signer's name and email, every event with its timestamp, the originating IP addresses, and a fingerprint of the document itself. Tamper-evident is the key property: the certificate is bound to the exact contents of the signed document, so if the PDF is altered after completion — a number nudged, a page swapped — the mismatch is detectable. What's in Signed's certificate is documented in Audit trail & certificate.
Why it matters legally
US law (the ESIGN Act and UETA) makes electronic signatures valid, but validity and *provability* are different things. In a dispute, the questions are: who signed, did they intend to, and has the document changed since? The audit trail is the ready-made answer to all three — attribution (the email and IP), intent (the logged signing action), and integrity (the tamper-evident seal). The legal groundwork is laid out in are electronic signatures legally binding?. Without an audit trail, an e-signed document isn't worthless — but you'd be assembling that evidence by hand, after the fact, from email threads.
What to check in any e-signature tool
- The certificate captures signer email, timestamps, and IP for every event — not just the final signature.
- It's attached to or delivered with the completed PDF, not locked behind the vendor's dashboard.
- It's tamper-evident — bound to the document's contents, not just stapled alongside.
- It's included on every plan, not reserved for an enterprise tier.
That last point is the quiet one: the audit trail is the legal substance of the product, and it shouldn't be an upsell. Signed includes the full audit trail and Certificate of Completion on its only plan — $20 per seat per month, unlimited documents (pricing). If you're weighing tools, the differences are price and scope, covered in the DocuSign alternative post.