I am about to start a contract with a remote client and want to start quickly. Rather than sending a signed contract by "snail mail" for them to sign and return, would it be enough to email the contract as a PDF attachment and ask them to reply by email stating their agreement to it? Would it stand up in a court if it had to go that far?

If the answer to the above is no, other than a physical signature on paper, what alternative ways are there to formally agree to a business contract that will stand up in court.

  • 1
    I know that emails can be forged, but so can signatures. An email has proof of sender such as email address (forgeable) and IP address (also forgeable) but surely these two provide more proof than a signature on paper (also forgeable). Dec 9, 2013 at 13:00
  • Does it matter what country you're in as to whether these answers are true or false?
    – jmort253
    Dec 10, 2013 at 0:52
  • @jmort253 I suspect that most western countries have similar laws though I am not sure. I am in the UK so I have a general and vague understanding of what the law requires here which seems to be quite open-minded (if that's an appropriate term) and flexible as to what is a contract. My understanding is that it boils down to being able to prove that someone did agree to do something - the form of the agreement being secondary. Hopefully, that helps to define potential answers... Dec 10, 2013 at 15:13
  • Contracts can be verbal only... contracts can be deemed to have been accepted (etc) The only "proof" required is that terms were agreed.
    – Andrew
    Dec 22, 2013 at 21:09

4 Answers 4


Preface: I am not now, nor have I ever been a lawyer. For legal advice it is always best to ask someone trained in the versatility of the law.

A contract is a written agreement which shows a "meeting of the minds". Email can be just that. It's my understanding that, while not as iron-clad as a physical signature, an email can be used to show intent and agreement. Just the same as a text message. Written evidence that a meeting of the minds was met is better than verbal agreement.

While email content can be faked, server and routing addresses really can't easily. Emails can be traced to every server they touched. And should the need arise, the sending server (the clients) could confirm that an email to [you] was sent on [date].

But again, I'd consult an attorney if this is something which really troubles you. I've never been in a position to file a claim on a client, but I do use email as written agreements.

Regarding PDFs, Adobe's PDF structure allows for digital signatures. This means there's really no need to print, sign, and scan anything. One can digitally sign a pdf, save it and then send it back.

  • Do remember though, that for it to work as well as Adobe advertises, they recommend you have a digital certificate as well; although I've signed many PDFs without one, and they've been fine
    – Canadian Luke
    Dec 9, 2013 at 19:12
  • Yeah, Adobe wants you to pay of course. It's not iron-clad, but it's more than nothing and harder to fake than a real signature in a PDF.
    – Scott
    Dec 9, 2013 at 19:14
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    The best solution, I believe, would be to do the above and post the contract by snail mail for a signature. The agreement by email reply will give me enough confidence to start the work and as I've divided the work and payments into phases, I can still demand the signed paper contract before moving on to the next phase. Dec 10, 2013 at 15:03
  • +1 for email+post. If starting on an email say-so with the promise of an inked signature to follow (rather immediately) isn't comfortable, you probably don't want to work with this client.
    – JRobert
    Nov 7, 2014 at 18:01

I actually cryptographically sign my emails* using an s/mime certificate, and my mail provider uses DKIM + SPF (gmail).

If you want real, unfalsifiable signatures, there is absolutely nothing else except strong cryptography. There never will be (In addition, you can do the same thing to PDFs using the same certificate).

I use the entire document, hashed, and then encrypt it with my private key and append my public key to documents (this ensures that the message was sent by me and has not been tampered with).

But I'm a web developer, systems administrator, and systems penetration tester, so I guess my clients are actually way more likely to even begin to understand what a digital signature even is.

If you want to use email as a signature or contract agreement, I strongly recommend that you cryptographically sign them. If this is not possible, then save the entire email, which will most likely have more headers than actual text. This is possible with almost all email providers.

The email will look a little something like:

To: [email protected]
From: [email protected]
Mailed-By: mail.smtp.google.com
Reply-To: [email protected]
Date: 0000-00-00T00:00:00Z
Content-Type: multipart/mixed; charset=utf-8; boundary=---EMAIL---
DKIM: abcdef1234567890

And so on. This is not perfect, and can still be spoofed, but is far better than a copy-pasted word document of an email (in fact, that is not actually an email1; a screenshot of your email program would do better)

* I have actually signed my housing tenant agreement using a 4096bit RSA key. It was accepted, to my astonishment.
1: I'm not a lawyer.

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    I would have considered cryptographic digital signatures (I use them in other situations) but for the slim-to-none chance of getting any client to do it or even understand it (and it's their signature that is most important to me) . :) Dec 10, 2013 at 14:59
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    @authentictech if it's on the client's end, save the entire email. You can then ask a court (if things come to that) to subpoena their email provider's records and see if they match, but that's about it.
    – Amelia
    Dec 10, 2013 at 17:59
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    See security.stackexchange.com/questions/1786/… regarding digital signatures weaknesses...
    – Pacerier
    Feb 11, 2014 at 16:28

What I do in the majority of contracts that I sign is to sign, date and scan the signature page, email it across as a PDF or even a jpeg and ask the other party to print, countersign and rescan before sending it back to me.

If you are concerned about the legality of this, which I haven't been you could look at using something like Adobe echo sign

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    I can fake anything in a PDF and jpg as well. That's not really a deterrent to someone who wants to be malicious. In fact, it's actually much easier to fake a PDF or jpg than an email.
    – Scott
    Dec 9, 2013 at 18:20
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    What @Scott says. Most email providers provide encrypted emails, and digitally sign outgoing mail to verify it is from you.
    – Amelia
    Dec 9, 2013 at 20:44

As per the E Signature Act 2000, it states that The ESIGN Act is a federal law passed in 2000 that grants legal recognition to electronic signatures and records if all parties to a contract choose to use electronic documents and to sign them electronically. No contract, signature, or record shall be denied legal effect solely because it is in electronic form. In addition, there is also the Uniform Electronic Transactions Act (UETA, 1999) which I haven't looked into personally but assume it's in relation to Esign act.

That being said, you may send them a fillable PDF document that allows them to type in their name and be accepted as a valid Electronic signature. There are many programs, such as adobe that can create a document to include a digital signature that would suffice and be considered as valid. Feel free to google the act further or electronic signatures and programs used to create documents for them.

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