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How to stop calendar invite spam with OnceHub

Even if you’ve spent just 10 minutes on the internet, you’ll know how pervasive spam is. Online appointment scheduling isn’t immune to the security risks and time-wasting that this plague of miracle cures, money-making schemes, and celebrity memes can cause. So, how does OnceHub jettison the junk… curtail the mail… toss the dross?

Calendar invite spam – and how to stop it

There are spammers or automated spam bots out in the wild and wooly web that can flood an online appointment scheduling booking page, slowing down servers and frustrating prospects and customers, who will struggle to find time in your calendar to meet. And there are any number of reasons why spammers might target your calendar.

Most often, they hope to use it against you by leveraging its functionality to repeatedly send out links to material designed to trick you out of money or expose you and your contacts to phishing schemes and malware. More targeted attacks could come from competitors wanting to harm your business.

OnceHub has heard prospective customers’ concerns about the possibility of spam bookings, and it’s all good news.

This all sounds pretty scary, but fear not. OnceHub has heard prospective customers’ concerns about the possibility of spam bookings, and it’s all good news. We have robust measures in place to help detect and stop calendar spam, so you can accept all bookings with confidence.

How OnceHub combats calendar invite spam

Spam bots can compromise booking pages in multiple ways, which is why it’s very important that your online appointment scheduling solution has multiple layers of defense, like we do at OnceHub. 

Here are some of the methods we use to stop calendar spam, ensuring you and your users experience trouble-free scheduling every time.

CAPTCHA challenges

CAPTCHA challenges require users to prove that they are human with a quick action, such as identifying distorted text or identifying parts of an image. We implement an invisible CAPTCHA, so your users won’t see it, but a bot will. A CAPTCHA challenge is difficult for bots to complete, so it helps to deter them from targeting booking forms with calendar invite spam. You can easily set CAPTCHA up in your OnceHub security settings.

Form validation

OnceHub’s online appointment scheduling has built-in form validation techniques to ensure that only valid and properly formatted data can be submitted through OnceHub booking pages. This includes checking the formats of email addresses, phone numbers, and other inputs to filter out spam submissions, as bots can’t always populate fields with relevant information.

IP address filtering

Blocking or restricting access to known spam IP addresses can help reduce spam submissions on booking pages. In the unlikely case that you detect spam bookings on your account, you can combat it by reaching out to our customer success team, who can investigate and block the offending IP address if required.

Rate limiting

OnceHub uses rate-limiting mechanisms to restrict multiple bookings made within a certain time period. This prevents bots from overwhelming the booking system with calendar invite spam. This measure is automatically in place when using OnceHub, so there’s no need to activate it from your end.


OnceHub’s interactive forms and chatbots – never to be confused with nefarious spam bots! – ask questions of visitors one at a time. Built to meet and greet visitors, qualify leads, and route them to the right resources, they can be set to ask very particular questions, all highly relevant to your business and visitors’ previous answers. An automated attack is unlikely to make sense of this rules-based or AI-driven to-and-fro, which will very likely preclude any bot being offered an appointment.


Take me to the bots!

Interested to know more about our chatbots, and how they could help your business better engage visitors to your website, spot and alert you opportunities, and improve the online appointment scheduling journey?
Click here

Top tips and tricks to stop calendar spam

  • Use conversational alternatives to static forms, like chatbots and interactive forms. They set spam bots an Olympic challenge to successfully pass as humans, and you’ll provide the real deal (your customers and prospects) with a more engaging and positive online appointment scheduling experience.
  • Enable CAPTCHA on your booking pages. These add a strong step in securing you against spam bookings by posing challenges designed to unmask and block spam bots.
  • Rely on other OnceHub security measures that can help prevent calendar invite spam, such as submission rate limiting and form validation.

Qualified and routed online appointment scheduling that prevents calendar invite spam

To engage with your audience effectively, you have to understand their unique needs, current priorities, preferred means of communication, and time limitations. You’ll experience better outcomes when you can put every conversation into context.

You’ll experience better outcomes when you can put every conversation into context. And OnceHub is all about context.

And OnceHub is all about context. We provide all the tools to engage visitors, qualify them as genuine, and suggest the most appropriate next steps for them to follow.

Using these tools is a great way to avoid spam bookings, as you can create different routes for your visitors. If they’re valuable, and answer the right questions, they’ll be shown a booking page. If not, you can direct them to an external link, without allowing them access to your schedule.

Stay safe and compliant with us

From the United States’ HIPAA to the European Union’s GDPR, OnceHub can help you meet your privacy and data protection obligations. Talk to us about your enterprise's specific needs

Spam can feel like it’s everywhere online, but, when you use OnceHub for online appointment scheduling, you don’t have to worry about spammers slowing you down or filling up your booking page.

Try OnceHub for more secure online appointment scheduling today!