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Core Concepts

Captcha

Protect the public subscribe form from automated abuse with a CAPTCHA provider

Kener can require a CAPTCHA challenge before sending subscribe verification emails. Go to Manage → Captcha Providers to configure any of the supported providers.

How it works

When a provider is enabled, Kener renders its widget on the public subscribe form and verifies the solved token server-side before sending the OTP email. Only one provider can be active at a time — enabling one disables the others. With no provider enabled, the subscribe form works as before.

Supported providers

Provider Key
hCaptcha captcha.hcaptcha
Google reCAPTCHA captcha.recaptcha
Cloudflare Turnstile captcha.turnstile

hCaptcha

Field Required Example
Site Key Yes 10000000-ffff-ffff-ffff-000000000001
Secret Key Yes 0x0000000000000000000000000000000000000

Create a site at hCaptcha to get your Site Key and Secret Key.


Google reCAPTCHA

Field Required Example
Site Key Yes 6Lc...
Secret Key Yes 6Lc...

Register a site at the reCAPTCHA admin console using the reCAPTCHA v2 "I'm not a robot" Checkbox type to get your Site Key and Secret Key.


Cloudflare Turnstile

Field Required Example
Site Key Yes 0x4AAAAAAA...
Secret Key Yes 0x4AAAAAAA...

Add a widget in the Cloudflare dashboard under Turnstile to get your Site Key and Secret Key.


Enable a provider

  1. Go to Manage → Captcha Providers.
  2. Select the provider from the left panel.
  3. Fill in the Site Key and Secret Key.
  4. Set Status to Enable.
  5. Click Save Changes.

A green dot next to the provider name indicates it is active on the public site.

Note

Changes take effect immediately — no restart required.