Practical Strategies for Blocking Fake User Signups and Bot Accounts

Dealing with automated bots creating fake user accounts is a common challenge for SaaS owners and web application developers. These bots can skew metrics, waste resources, and create security vulnerabilities. Fortunately, a combination of network-level and application-level strategies can significantly reduce spam registrations.

First Line of Defense: Network-Level Blocking

A powerful first step is to block malicious traffic before it even reaches your application. Using a service like Cloudflare allows you to implement robust security rules with minimal effort. Key features include:

Geo-blocking: If you notice that the vast majority of fake signups originate from specific countries, you can block traffic from those regions entirely.
Bot Blocking: Cloudflare's bot detection can identify and challenge or block automated traffic based on its behavior and signature, effectively filtering out a large percentage of spam bots.

Application-Level Anti-Bot Techniques

For bots that make it past the network-level defenses, you can implement clever checks directly in your signup form.

Honeypot Fields: This classic technique involves adding an extra input field to your form that is hidden from human users via CSS. Since many bots simply fill out every field they find, you can instantly reject any submission where this hidden "honeypot" field has a value.
Simple Human Verification: Instead of forcing users to solve a complex and often frustrating CAPTCHA, a simpler human test can be just as effective. One highly-recommended technique is to add a text input field with a placeholder like "I am human" and instruct the user to type that exact phrase to proceed. Simple bots often fail this test, which requires parsing instructions and interacting with the form in a human-like way.
Domain and TLD Blocklists: If you consistently see fake accounts from specific email domains (e.g., @mail.ru, @bk.ru), you can add them to a blocklist within your application's logic. While effective, this requires ongoing maintenance as spammers switch domains. For a more aggressive, short-term solution, you could block an entire top-level domain (TLD), such as .ru. This is a blunt instrument that may block legitimate users, but it can be a useful temporary measure to stop a massive spam wave.