How can I prevent nefarious email signups using rate limiting, reCAPTCHA, and double opt-in?

Email marketer from MarketingProfs recommends using a combination of CAPTCHA, rate limiting, and email verification to prevent fake signups. They emphasize the importance of monitoring signup patterns for suspicious activity.

Email marketer from Quora recommends implementing a challenge question that requires human intelligence to answer. They suggest using questions that are difficult for bots to solve, such as 'What is the second letter of your favorite color?'

Marketer from Email Geeks suggests ReCaptcha is great and will prevent 99% of bots. Also, rate limiting is great either by IP or other fingerprints, and to monitor metrics for spikes.

Email marketer from ZeroBounce suggests using advanced IP address validation to identify signups originating from known bot networks or suspicious locations.

Email marketer from Reddit suggests implementing rate limiting based on IP address and email address to prevent bots from creating multiple accounts within a short period. They advise adjusting the limits based on typical user behavior.

Email marketer from Stack Overflow suggests using a JavaScript challenge on the signup form to ensure that a real browser is submitting the form. They also recommend analyzing the HTTP headers of signup requests to identify suspicious patterns.

Marketer from Email Geeks suggests using both rate limiting and reCAPTCHA, emphasizing behavioural scoring/bot detection. They suggest using reCAPTCHA sparingly due to its intrusive nature.

Email marketer from Neil Patel suggests implementing honeypot traps, which are form fields invisible to users but easily detected by bots. If a bot fills them out, the signup can be blocked, as this indicates non-human activity.

Email marketer from Email Vendor Selection suggests monitoring signup sources and blocking suspicious referrers. They also recommend implementing email verification to confirm that the email address is valid and active.

Email marketer from Email Marketing Forum recommends using a timestamped hidden field. Upon submitting the form, compare the current time with the timestamped time. If the form was submitted too fast, the user is very likely a bot.

Marketer from Email Geeks warns that when using rate limiting, to remember to whitelist the site IP if the sales team is doing events where signing up for the list is part of their contest/offer/whatever. And to remember to tag those signups as promo signups so you can drop them quick when it turns out they only signed up for the promo.

Marketer from Email Geeks explains that reCAPTCHA can be configured to operate silently, presenting challenges only when uncertainty arises.

Email marketer from Bouncer recommends implementing an email verification process as a key step of signup to ensure the email is not a disposable email, or a honeypot.

Marketer from Email Geeks recommends using all methods and suggests also using live email address validation tools.

Expert from Word to the Wise shares that there are initiatives like the rel=webform header. The idea is the form itself would be able to announce to systems that it is a form, where it lives and what the purpose is of the form submission. If the mail stream sees an IP address has sent 1000 different bounces, that says something about the quality of senders coming from that location. With web forms though, an IP address may be sharing a web form used by 100 legitimate users, and 50 malicious users. It would be useful to see a header inserted by the web form to distinguish it from other activity from that IP.

Expert from Spam Resource shares that CAPTCHAs can deter bots. Alternatives like honeypots (hidden fields) or challenge questions can be less intrusive. Rate limiting based on IP address can prevent rapid-fire account creation.

Expert from Email Geeks advises to track subscriptions by email address across all customers. If you see a spike, that's a problem.

Expert from Email Geeks suggests rate limiting, recaptcha and double opt-in are decent approaches. Also Zerocaptcha is better than Recaptcha. Further options are audit trails, hidden form fields with magic words, javascript, checking peer IP reputation via fraud and blogspam blacklists, and talking with your in-house data people about tools or procedures to identify issues and, just as importantly, recover from them.

Expert from Email Geeks notes that live email validation is only useful for catching typos from real users, not for preventing bot signups.

Expert from Spam Resource explains that Email address validation is a critical step. Tools can check the syntax, domain existence, and whether the address is disposable or from a known spam source.

Expert from Email Geeks explains that live validations won’t stop bot signups because the point of those is to slam a real email address with mail

Documentation from Mailjet explains that double opt-in requires users to confirm their subscription by clicking a link in a confirmation email. This ensures that the subscriber is a real person and that they want to receive emails from you, helping to maintain a clean and engaged email list.

Documentation from Microsoft Azure explains how to implement rate limiting in Azure API Management to protect backend services from overload. It describes different rate limiting policies that can be applied to API endpoints.

Documentation from Cloudflare shares that Rate limiting protects infrastructure from denial-of-service (DoS) attacks, brute-force attempts, and application layer attacks. It does this by limiting the number of requests a visitor can make to a website or API within a certain timeframe.

Documentation from Google Developers explains that reCAPTCHA protects websites from fraud and abuse. reCAPTCHA uses advanced risk analysis techniques to tell humans and bots apart. This allows valid users to pass through easily, while blocking automated abuse.

Documentation from OWASP shares that rate limiting is a crucial security control to prevent abuse and protect against denial-of-service attacks. It suggests implementing rate limits at different layers of the application to provide comprehensive protection.