A sequential signing order sends a document to each signer one after another, so signer two cannot sign until signer one has finished, while parallel signing sends it to everyone at once and lets them sign in any order. Sequential signing suits documents where order genuinely matters, for example where a manager must approve before a director countersigns, or where later signers want to see that earlier parties have committed. Parallel signing is faster and suits documents where every signer is equal and order is irrelevant, such as a mutual NDA between two companies. Most delays in getting a contract signed come from choosing the wrong flow, not from lazy signers. This guide explains the difference, when each one wins, and how 99 Data Rooms lets you pick. It is general information, not legal advice.
The choice sounds trivial, but it quietly shapes how fast your document gets signed and how well it holds up afterwards. Get it right and signing feels effortless. Get it wrong and you spend a week chasing people who were waiting on each other.
What sequential signing actually means
Sequential signing enforces an order. The document goes to the first signer, and only once they have signed does it move to the second, then the third, and so on. Nobody further down the chain even sees the request until it is their turn.
The strength of sequential signing is control over sequence. There are documents where the order is not just a preference, it is part of how the document works. A board paper that a company secretary prepares, a chair approves, and directors then countersign has a natural order baked in. An offer of employment that a hiring manager signs before it goes to the candidate has an order for a reason: you do not want the candidate signing something the company has not yet committed to. In these cases, sequence carries meaning, and enforcing it prevents awkward situations like a junior party committing before their own side has approved.
The weakness is speed. A sequential flow is only as fast as its slowest link, in order. If signer two is on holiday, signers three and four are stuck behind them even if they were ready to sign on day one. This is why sequential flows need active chasing: when the whole chain waits on one person, you need to know who that person is and nudge them specifically. Our guide on how to chase a signature without starting over covers reminding and extending the deadline for exactly this situation, without re-issuing the document.
What parallel signing actually means
Parallel signing sends the document to everyone at the same time. Each signer can sign whenever they like, in any order, and the request completes when the last person signs.
The strength is obvious: speed. Nobody waits for anybody. If all four signers happen to be at their desks, the document can be fully executed in minutes rather than days. For any document where the signers are peers and order carries no meaning, parallel is almost always the better choice. A mutual NDA between two businesses is the classic example: both sides are equal, both are disclosing, and there is no logical reason one must sign before the other. Our mutual NDA template guide walks through that document, and it is a textbook case for parallel signing.
The weakness of parallel signing is that it gives up the very control that sequential provides. If it genuinely matters that the company signs before the candidate, or that approval precedes execution, parallel signing cannot enforce that. It also means a later signer cannot rely on seeing that earlier parties have already committed, because there may be no "earlier".
How to choose: a simple test
The decision comes down to one question: does the order in which people sign carry any meaning?
If the answer is no, use parallel. Equal parties, no approval hierarchy, no "this side must commit first" logic, then let everyone sign at once and get the document done faster. Mutual NDAs, simple two-party service agreements between equals, and most documents where both names are peers fall here.
If the answer is yes, use sequential. Approval chains, offer letters, board documents where a chair or secretary signs before directors, or any case where a later signer should only be asked once earlier parties have committed, these need order, and sequential enforces it.
A useful middle consideration is the number of signers. With two equal parties, parallel is nearly always right. As the number of signers grows, the cost of a wrong order grows too, and so does the value of per-signer tracking, because you need to know exactly where a document is stuck. Whichever flow you choose, being able to see who has signed and who has not is what turns a stalled document into a single, specific chase rather than a group email.
Whatever you pick, the flow does not change the legal weight of the signatures. Electronic signatures are admissible for most commercial documents in England and Wales whether they are collected one at a time or all at once, with the usual narrow exceptions such as deeds and land transfers that carry extra formality (see our guide on whether electronic signatures are legal in England and Wales). Order is about workflow, not enforceability.
Why the audit trail matters either way
Regardless of which flow you use, what you want at the end is a clean record of who signed, in what order, and when. This is where the e-signature audit trail earns its keep. A good audit trail records each signature with a timestamp, an IP address, the signer's intent to sign and a fingerprint of the document, so the sequence is captured as fact rather than assumption.
For sequential signing this is doubly useful, because the order itself may be legally or commercially relevant, and the trail proves it. For parallel signing it still matters: even when order is irrelevant, you want an unambiguous record that every named party signed the same version of the same document. Either way, the audit certificate is the difference between "we think everyone signed" and "here is exactly who signed, when, and from where".
How 99 Data Rooms handles signing order
In 99 Data Rooms, e-signature is available from the Pro tier upward, and you choose the signing flow when you send a document out. You can set a sequential order, so each signer is invited only once the previous one has signed, or send it to everyone in parallel for speed. Either way you get a live, per-signer status view: not opened, opened, or signed. That tracking is what makes both flows manageable, because you always know who the request is waiting on.
If a signer stalls, you remind that specific person and, if needed, extend the deadline rather than cancelling and re-issuing, which keeps the audit trail intact. When the last signature lands, the executed PDF comes back with an audit certificate capturing who signed, when, their IP, their intent and a SHA-256 fingerprint. Because the document sits inside a tracked, revocable room rather than an inbox, you also keep control the whole way through, and can revoke access in one click if a deal falls over. Better still, you can draft the document from vetted England and Wales clauses first, then send it straight to signature in the browser without leaving the platform. If getting signed paperwork back from clients is your main pain, our roundup of the best ways to collect signed documents from clients puts the whole loop in context.
Pick the right flow, for free
You can draft, gate, send for signature and choose sequential or parallel signing, all inside 99 Data Rooms. The free tier gives you three rooms and twenty-five active links forever, with no card required, and e-signature unlocks from Pro. Start for free, or see the full e-signature feature to understand how signing order, reminders and audit certificates fit together. The wider platform is in beta and improving fast, but the signing loop already works end to end.
Sources
- Electronic signatures, admissibility and the formalities for deeds and land transfers in England and Wales: Law Commission, Electronic execution of documents (2019), https://lawcom.gov.uk/project/electronic-execution-of-documents/ ; HM Land Registry Practice Guide 82, https://www.gov.uk/government/publications/electronic-signatures-accepted-by-hm-land-registry-pg82
Is sequential or parallel signing more legally valid?
Neither is "more valid". The signing flow is a workflow choice and does not change enforceability. Electronic signatures are admissible for most commercial documents in England and Wales in either flow, with narrow exceptions such as deeds and land transfers (see Sources). This is general information, not legal advice.
When should I definitely use sequential signing?
Use sequential when order carries meaning: approval chains, offer letters where the company signs before the candidate, or board documents where a chair or secretary signs before directors. If a later signer should only be asked once earlier parties have committed, sequential enforces that.
When is parallel signing the better choice?
Use parallel when signers are equal and order is irrelevant, such as a mutual NDA between two businesses. It is faster because nobody waits for anybody, and the request completes as soon as the last person signs.
Does the signing order show up in the audit trail?
Yes. The audit trail timestamps each signature, so the order is captured as fact. This is particularly useful for sequential flows where the order itself may matter.
What happens if one signer in a sequential flow goes quiet?
Everyone behind them waits, so you chase that specific person. In 99 Data Rooms you can send them a reminder and extend the deadline without re-issuing, as covered in our guide on chasing a signature without starting over.
Can I change the flow after sending?
It is cleaner to choose the right flow before sending. If you picked the wrong one, you would generally cancel and resend, which is why the choose-first test in this guide is worth the thirty seconds it takes.