How do I check a customer properly before opening a credit line for them?

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A bad credit account doesn't usually announce itself upfront, it shows up weeks or months later as a past-due invoice that never gets paid, sometimes from a business that never really intended to pay on time, sometimes from one that was simply in worse financial shape than their paperwork suggested. The signing step matters, but it's the smallest part of actually protecting yourself here, and treating it as the main safeguard is a common, costly mistake.

It's worth naming the specific instinct that leads suppliers astray here: a signed application, especially one that went through a secure link with a fancy audit trail and a phone verification code, feels thorough. It feels like due diligence happened. But all of that machinery is checking one narrow thing, that the right person clicked and typed, not whether that person's business can actually pay its bills on the schedule you're extending. Confusing a secure signature with a creditworthiness check is how businesses end up surprised by a loss they thought their process had already guarded against.

The no-tool way: paper, email or a phone call

A paper credit application, filled out and signed in person, works fine as a document, but it carries exactly the same limitation as a digital one: it's a signed statement of intent, not a verification of financial standing. Calling a few of the trade references listed on the application is still one of the most useful, genuinely free steps available, and it's one plenty of suppliers skip simply because it takes more effort than clicking "approve."

A quick, honest note on why that call gets skipped so often in practice: it's genuinely tedious, and most of the time nothing's wrong, so it starts to feel like a formality that's safe to drop. The problem is you only find out it mattered on the one application where something actually was wrong, and by then the account is already open. Building the reference call in as a fixed, non-optional step, rather than a judgment call made fresh each time, is what keeps it from quietly disappearing under time pressure.

The software options, from simple to most capable

DocuSeal

DocuSeal, an open-source e-signature tool available self-hosted for free or as a paid cloud product, offers SMS and OTP verification on its Pro cloud plan at $20 a user a month, with 20 verifications included monthly and $0.20 each after that.

Zoho Sign

Zoho Sign, the e-signature product inside Zoho's wider business software suite, includes SMS delivery and verification on its Standard, Professional and Enterprise tiers, not on its free plan. Zoho's pricing page didn't show dollar figures for those paid tiers when I checked, only a note about a 20% annual billing discount, so confirm an actual quote directly.

QuickSigner

QuickSigner is an electronic signature tool: upload a document, place signature fields, and send a secure link that works from any device, no account required for the signer. On its Professional plan, $15 a user a month (20% cheaper billed annually), it adds a one-time phone code before signing can complete. This confirms the signer has access to the phone number on file, not that the business behind the application is actually creditworthy, which is a separate step entirely. Confirm current pricing on QuickSigner's own site.

Step by step: opening a credit line properly

1. Get the signed application, with full legal business name, owner or officer details, and trade references, through whichever signing tool you use.
2. Add a phone code check if your tool offers it, as a standing step for new credit applicants specifically, since this is exactly the kind of higher-stakes signature worth the extra friction.
3. Run actual credit and bank checks outside the signing tool entirely, a business credit report, a bank reference, calls to the trade references listed. None of this happens inside an e-signature platform, it's a separate process you run before approving anything.
4. Set a conservative starting limit, raising it only after the customer has built a real payment history with you. This single habit prevents more bad-debt losses than any amount of upfront verification, since it caps your exposure while you're still learning how reliably they actually pay.

What a phone code is and isn't

It's worth being precise here because it's easy to feel more protected than you actually are. A one-time code sent to a phone confirms the signer has access to that specific number, which is a real, useful check against someone else impersonating the applicant using a compromised email. It tells you nothing about the applicant's actual financial health, payment history, or even whether the business itself is legitimate rather than a shell set up specifically to run up unpaid credit. Those are different risks, addressed by different tools: a credit check addresses financial risk, a phone code addresses identity-at-signing risk. Treating either one as covering the other is how credit losses happen.

A business credit report, pulled through a standard commercial credit bureau, looks at payment history with other suppliers, public filings, and sometimes the age and size of the business, none of which an e-signature tool has any visibility into at all. That report, together with a couple of direct calls to the trade references listed on the application, gives you the actual financial picture. The signing tool's job is narrower and more mechanical: making sure the right person agreed to the terms, not telling you whether those terms are a safe bet.

How I'd approach this

I'd tell a supplier extending credit to new customers that the signing tool and its verification features are the smallest lever they have here, not the main one. The biggest lever, by a wide margin, is starting conservative. A new account getting a $2,000 limit instead of the $15,000 they asked for isn't an insult, it's standard, sensible practice, and a customer who's genuinely a good long-term relationship won't mind proving it over the first few invoices.

Here's the math that makes this worth insisting on even when a new customer pushes back. If a supplier opens new accounts at the requested limit roughly twenty times a year, and even one in twenty turns into a full default at an average $15,000 exposure, that's a $15,000 loss against whatever margin was earned on the other nineteen accounts combined, often wiping out the profit from all of them. Capping new accounts at $2,000 until a payment history builds caps that same bad-case loss at a fraction of the amount, while barely slowing down the nineteen good customers who'll happily pay on time and earn a higher limit within a few invoices anyway. I've seen suppliers skip this step because a bigger limit feels like better customer service upfront, only to eat a five-figure loss from one account that turned out to be exactly the risk a conservative starting limit was built to contain. If you're setting up a credit application and onboarding process and want the verification, the credit check, and the limit escalation rules all built into one consistent workflow instead of handled ad hoc, that's worth doing properly.