For most small firms the engagement letter is the first document a new client signs, and the one that matters most later if there is a fee dispute or a question about scope. Sending it through a separate e-signature service means another subscription, another login, and a signed PDF someone has to download and file by hand. You often cannot tell whether the client has even opened it.
What the law says about electronic signatures
The federal ESIGN Act provides that, for a transaction in or affecting interstate or foreign commerce, a signature, contract or other record may not be denied legal effect, validity or enforceability solely because it is in electronic form. It does not reach everything. Section 7003 excludes, among others, wills, codicils and testamentary trusts, state family law matters such as adoption and divorce, and court orders, notices and official court documents. Where a law requires information to be given to a consumer in writing, ESIGN adds consent and disclosure steps before an electronic record can take its place.
Your state’s own electronic transactions law applies as well and can draw its own lines. A document that has to be notarized, or that your state requires to be signed in ink, still needs paper. None of this is legal advice about a particular document; it is the frame the software works within.
How signing works in Coil
- Click to sign in the browser. The signer types their name and ticks an affirmative checkbox.
- A certificate of who, when, where and what. Each signature records the signer’s name, IP address, browser user agent and timestamp, with a hash of the document and a hash of the signature, so any later change to the document would not match the record.
- Immutable once signed. A signed document cannot be edited afterwards.
- Decline with a reason. A signer who will not sign can say why, and the reason is on the record.
- Signed copy to both sides. The signed PDF goes to the client and to the firm, and stays on the matter.
- Open tracking on engagement letters. You can see when the client opened the letter, before they sign it.
- Part of intake and the portal. When a lead is converted, the engagement letter goes out in the same step that opens the matter, and clients can sign from the portal. Client-facing pages are in English or Spanish.
- Any document. Engagement letters are the usual case, but any document on a matter can go out for signature.
What Coil does not do
Coil does not notarize. It does not check a government ID or ask identity questions before someone signs; it uses the click-to-sign model most e-signature products use. It does not decide whether a particular document may be signed electronically in your state, which is your call. And it is not a separate product with its own price: e-signature is one of the tools every Coil firm gets.
A routine that works
Send the engagement letter from the matter, or from the intake conversion for a new client. Check whether it has been opened before you follow up, since an unopened letter needs a different nudge from one that has been read and left. If the client declines, the reason they gave tells you what to change before you send it again. Once it is signed, there is nothing to download or file, because the signed copy and its certificate are already on the matter.
Why it belongs in the practice system
When the signature lives on the matter, the record of what the client agreed to sits beside the work and the bills that follow from it. Nobody has to remember to file the signed copy, and the certificate is there if the scope of the engagement is ever questioned. Coil is free during the beta, and beta firms keep founding pricing when paid plans start.
Questions
Is an electronic signature on an engagement letter valid?
Under the federal ESIGN Act, a signature or contract in a transaction affecting interstate commerce cannot be denied legal effect solely because it is electronic. Coil's click-to-sign, with a typed name, an affirmative checkbox and an audit record of signer, IP address, user agent, timestamp and document hash, is the same model most e-signature products use. It is not notarization, some documents are excluded from ESIGN, and your state's own law applies, so use paper where your state requires it.
Can I see whether the client opened the engagement letter?
Yes. Coil tracks when an engagement letter is opened, so you know whether the client has seen it before you chase a signature.
What does the signing certificate record?
The signer's name, IP address, browser user agent and the time of signing, with a hash of the document and a hash of the signature. The document cannot be changed once it is signed.
Can I send documents other than engagement letters?
Yes. Any document on a matter can go out for signature, and the signer can decline with a reason instead of signing.
Sources
Last checked October 28, 2026.