https://yegorov.github.io/tags/otp/ Recent content in OTP on Artem Yegorov Hugo en Thu, 22 Oct 2026 07:25:04 +0000 https://yegorov.github.io/notes/generating-random-numeric-code-in-ruby/ Thu, 22 Oct 2026 07:25:04 +0000 https://yegorov.github.io/notes/generating-random-numeric-code-in-ruby/ <p>If you work in web development, you&rsquo;ve almost certainly had to generate random numeric codes like OTPs for logins or transaction verifications sent via SMS or email. It seems like a straightforward task, and your first instinct might be to reach for <a href="https://docs.ruby-lang.org/en/master/Kernel.html#method-i-rand" class="external-link" target="_blank" rel="noopener"><code>Kernel#rand</code></a>. But that method isn&rsquo;t designed for cryptographically secure random numbers, so the <a href="https://docs.ruby-lang.org/en/master/Random.html" class="external-link" target="_blank" rel="noopener">documentation advises</a> switching to a safer alternative: <a href="https://docs.ruby-lang.org/en/master/SecureRandom.html" class="external-link" target="_blank" rel="noopener"><code>SecureRandom#rand</code></a>. Next comes requirements that can vary depending on the use case: do all ten digits need to be included in the code, do you need to exclude certain numbers, or do you need to mix in alphanumeric characters.</p>