Basecamp's Home Page Gave Me Two Valid Phone Numbers. Both Were Calendar Day Numbers
I run a visa agency in Bali. The other half of my week goes into Apify Actors, and one of them does something that sounds trivial until you try it: you give it a list of websites, it gives you back one row per website with the company's e-mail addresses, phone numbers, socials, contact page and postal address, each contact carrying the page it was found on. Fetching the pages is the easy part: a…
In a recent incident, a visa agency operating in Bali encountered a peculiar issue with Basecamp's home page. The agency's Apify Actors were designed to extract contact information from websites, including emails, phone numbers, and social media profiles. While the process of fetching pages was relatively straightforward, the extraction of accurate contact data often proved challenging due to the prevalence of fake contact information on marketing pages.
During a particular run on October 13-14, 2026, the Apify Actors encountered three instances of what appeared to be valid phone numbers on Basecamp's home page. The first number was +1 301 516 1718, and the second was +1 301 213 1415. These numbers were extracted from the page text and not from the structured data present on the page.
Upon closer inspection, it was discovered that these numbers were actually part of a calendar view displayed on Basecamp's home page. Upon removing the HTML tags, the numbers formed a sequence of ten-digit day numbers: 3015161718 and 3012131415.
The issue arose because the phone number validation tool used, libphonenumber-js, correctly identified the numbers as valid according to the North American numbering plan. However, these numbers were not assigned to any specific individual, making them invalid for business purposes. The agency had implemented a length floor rule to filter out numbers that were too short, as well as a numbering-plan validator to ensure the numbers were valid.
However, these measures were ineffective in distinguishing valid contact numbers from fabricated calendar day numbers.
In contrast, Basecamp's actual contact information on the same page was easily identifiable through its rank and schema.org markup. The agency's contact email, jason@basecamp.com, was clearly marked as a valid email address with a rank of 4. This information was not present on the fabricated numbers, highlighting the distinction between legitimate and fabricated contact data.
The incident also revealed the presence of placeholder email addresses on Basecamp's home page. These addresses were present in the i18n bundle for the mock checkout graphic on the page and were not actual contact information. The agency's placeholder filter successfully caught most of these addresses, with one exception – jane.diaz@stripe.com. This address was flagged as a potential fake due to the domain (stripe.com) not matching the expected domain for the mock checkout graphic (basecamp.com).
Despite the agency's attempts to filter out fake contact information, the issue persisted. The deliverability add-on did not provide any additional value in this case, as the fake email address passed the deliverability check. This underscores the challenges faced in accurately identifying valid contact information in today's digital landscape, where the line between legitimate and fabricated data is often blurred.
Written by urgent.news from Dev.to's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
