What makes an e-signature legally binding?

The general rule: e-signatures are usually valid

In the UK, electronic signatures are recognised for most contracts, supported by the Electronic Communications Act 2000 and confirmed by a 2019 Law Commission report. In the EU, the eIDAS Regulation gives electronic signatures legal effect. Many other countries have equivalent laws (for example, the ESIGN Act in the United States).

For everyday commercial work, a proposal, a statement of work, an agency engagement, you generally do not need a wet-ink signature, a witness, or paper. An electronic signature is enough to form a binding agreement. A small number of document types (some property, wills and similar) have stricter formalities, which is one reason to get advice on anything unusual.

The three things that actually matter

Whether a signature holds up rests less on the technology and more on three principles:

• Intent to agree. The signer must be clearly agreeing to the terms, not just opening a

file. A deliberate signing action against the document establishes this.

• Attribution. You must be able to reasonably link the signature to the specific person who

made it. An email address, an access route, a timestamp and an audit trail all support attribution.

• Integrity of what was signed. You need to show what was agreed and that it hasn't

changed since. This is where a preserved, immutable copy of the signed version matters most.

Meet those three and you have an agreement that's both binding and defensible.

Evidence is what wins disputes

A signature is only as useful as the evidence around it. If a client later says "that's not what I agreed to", you want to point to a clear record, not reconstruct a story from emails. A strong evidence trail typically includes:

• Who signed, identified by email or account.
• When they signed, with a reliable timestamp.
• What they signed, an exact, unaltered copy of that version of the document.
• The sequence of events, captured in an audit certificate.

This is the practical difference between "we're pretty sure they agreed" and "here is exactly what they agreed, on this date". The hand-off into delivery also benefits, because the frozen version is the one your team builds against.

Levels of e-signature (briefly)

Under eIDAS, there are three tiers: simple electronic signatures, advanced (AES), and qualified (QES), which carries the highest assurance and legal weight. For most agency proposals, a simple or advanced electronic signature with a good audit trail is entirely appropriate. Qualified signatures involve identity verification via a trust service provider and are usually reserved for higher-stakes or regulated contexts. Match the level to the risk.

How ScopeDeck approaches this

ScopeDeck's native e-signature is designed around those principles: it's legally binding, supports multiple signers and a signing order, records an audit certificate of the sign-off, and captures an immutable accepted snapshot of the exact version agreed. If the scope changes afterwards, that's a tracked amendment with its own record, not a silent edit to a signed document. In other words, it's built to give you intent, attribution and integrity for standard commercial proposals.

For whether it's worth using at all, see do agencies need e-signatures; for speed, see get proposals signed faster.

Again: general information, not legal advice, take professional advice for anything high-value or unusual.