How do I get notified the moment a contract is signed?

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Webhooks, in plain words

A webhook is just an automatic message a service sends to a URL you provide, the moment something specific happens on its end. There's no polling, no checking back every few minutes, the esign tool's server reaches out to tell you the instant a document is fully signed, with details like which document, who signed it, and when. The alternative, checking a dashboard or inbox manually, is exactly the habit a webhook is built to replace. The same idea works for form enquiries, as in routing website leads to where you follow up.

QuickSigner, an e-signature platform for signing PDFs and Word documents from any device with AATL-certified, legally binding signatures, confirms webhook support for completion notifications as part of its eSignature API, available on its Professional plan at $15 a month per user (or $144 a year with its 20 percent annual discount), which includes 50 free API sign requests before its $0.30-per-request rate applies. That webhook is the actual mechanism this whole alert setup depends on.

Options for non-developers

You genuinely don't need to write code to turn a webhook into a Slack message or an email. Three realistic paths, in order of how much setup they take:

• Zapier's "Webhooks by Zapier" trigger, paired with a Slack or Gmail action. This is the most beginner-friendly of the three, with the most polished point-and-click interface for mapping webhook fields into your alert message.
• Make's HTTP or Webhooks module, paired with its Slack or Email action. Make's visual flow view makes it easier to see exactly what data arrived in the webhook before deciding what to do with it, which helps if you're not sure yet what fields you'll actually need in the alert.
• n8n's native Webhook node, paired with its Slack or Email node. This is the most flexible of the three and free to self-host indefinitely, but it assumes slightly more comfort with technical setup than Zapier or Make, since you're running your own instance rather than using a fully hosted service.

Any of the three works. Zapier and Make are faster to get started with if this is your first automation; n8n is cheaper at real volume and more flexible once you're comfortable with it. The underlying mechanics are identical regardless of which one you pick: catch the webhook, read the fields you care about out of it, and fire a message. The platform choice mostly comes down to which one you already have an account on, or which pricing model fits your volume best. For the sending side of these tools, see adding a signing step to Zapier, Make or n8n.

Setup guide

1. Get your webhook URL. Create a new Zap, Scenario or Workflow in whichever tool you're using, starting with its Webhooks trigger, which generates a unique URL for you to use in the next step.
2. Register that URL with QuickSigner. Point QuickSigner's webhook configuration (through its API settings) at the URL generated in step one, so it knows where to send the completion notification.
3. Send a real test document through to completion. Sign a test document yourself end to end so a real webhook actually fires, rather than guessing at what the payload will look like.
4. Map the fields you want in your alert. Pull the document name, signer name and completion time out of the webhook's payload and drop them into your Slack message or email template.
5. Add the Slack or email action. Point it at the right channel or address, write a short, clear message template ("[Document name] was just signed by [signer name]"), and save it.
6. Test it again with a second real document before trusting it for anything client-facing, since the first test often reveals a field name or formatting issue the second one catches cleanly.

Common mistakes with signature alerts

• Alerting on the wrong event. Some esign tools fire a webhook on every status change, document sent, viewed, partially signed, not just fully completed. Filter the automation to trigger only on the specific "completed" or "fully signed" status, or you'll end up with a flood of alerts for every intermediate step instead of the one that actually matters.
• No message context. An alert that just says "a document was signed" with no client name or document type attached forces whoever reads it to go look it up anyway, which defeats the purpose. Always map in the actual document name and signer details from the webhook payload.
• One single point of failure for something important. If the entire business depends on knowing the moment a high-value contract is signed, a Slack alert alone, with no email backup and no manual fallback check, is a risky amount of trust to place in one notification channel.
• Forgetting to test with a real multi-signer document. If your documents often need more than one signature, test what the webhook sends when the first signer finishes versus when the last one does, since "signed" and "fully completed" aren't always the same event.
• Letting the alert message go stale. If you later add a new document type or change what field matters most to you, update the message template too, rather than leaving it describing a workflow that's since changed.

Cost at different volumes

At light volume, a handful of contracts a month, Zapier's free 100-task tier or Make's free 1,000 operations a month both comfortably cover a simple webhook-to-Slack alert, since this kind of automation is usually just two steps per document. Past roughly 40 to 50 documents a month on Zapier specifically, you'll likely need its Professional plan, confirmed at $19.99 a month billed annually, for the webhook trigger and any filtering logic. Make's free tier tends to stretch further at similar volumes since it counts by individual operation rather than by whole Zap. n8n, free to self-host or starting at €20 a month on its Cloud Starter plan for 2,500 workflow executions, is worth considering if you're already running other automations on it, since adding one more simple alert workflow costs nothing extra beyond your existing plan. Some tools also connect straight to Gmail, Google Drive and Sheets without any webhook.

A worked example

Say you run a small real estate brokerage closing roughly 20 signed agreements a month and want your whole team to see in Slack the moment each one lands, rather than one person checking email and relaying it verbally. A Zapier flow using QuickSigner's completion webhook as the trigger and a Slack "send channel message" action as the only step covers this in two tasks per document, comfortably inside Zapier's free 100-task monthly tier at that volume, meaning the entire alert system costs nothing beyond the QuickSigner subscription itself. The detail worth getting right the first time: deciding whether the alert should go to a shared channel everyone sees, or a direct message to just the agent on that deal, since routing it to the wrong place defeats the purpose just as much as no alert at all. The signed file itself can also be filed for you, as in saving signed contracts to Drive or Dropbox automatically.

How I'd approach this

The part people skip, and the part that actually matters most, is deciding what should happen after the alert fires, not just that it fires. A Slack message nobody acts on is barely better than no notification at all. When I set this up for a client, I ask what the very next action should be once a contract's signed, kick off onboarding, trigger an invoice, start a project, and build the alert to point directly at that next step, not just as a passive notice. If you're setting up QuickSigner's webhook for the first time and want it wired into something more than a notification, a real next action in your actual workflow, that's worth a proper conversation rather than another isolated Zap. Get in touch if that's where you're headed.