Invisible CAPTCHA for WordPress
Protect your WordPress forms against spam – invisibly, without image puzzles, with the official plugin. Which form plugins we have tested is shown below.
1,000 requests/month for 1 domain · No credit card required
Widget submissions and server-side checks each count as a request.
SilentShield is an invisible CAPTCHA alternative for WordPress. The official plugin is tested for Contact Form 7, Fluent Forms, WordPress comments, WordPress login, WordPress registration, WooCommerce checkout (classic), WPForms, WooCommerce checkout (block checkout), Elementor Forms, and Avada Forms (checked on October 7, 2026 with plugin 2.15.14 and WordPress 7.1.2). It recognises Gravity Forms and Ninja Forms, but they are not fully tested. It sets no cookies for the bot check and does not track visitors across websites; the check runs on servers in Germany by default.
Form plugins at a glance
Setup in 4 steps
Create a free account
Register with your email address and confirm it with the link in the confirmation email. No credit card required.
Set up your website and get the key
In the dashboard, open “API keys” and create a new API key for your domain. The key is bound to that domain; copy it.
Install and activate the plugin
In WordPress, open Plugins → Add New, search for “SilentShield”, install and activate it. Then open “SilentShield → API / SilentShield”, paste the key, click “Validate”, switch on “Activate API” and save.
Enable your forms and check the result
Under “SilentShield → Forms”, switch protection on for the form plugins that are tested. Then submit one of your forms by hand: the submission appears in the dashboard with its verdict. The site must run over https.
Why Not reCAPTCHA for WordPress?
| Feature | SilentShield | reCAPTCHA (WordPress) |
|---|---|---|
| Visibility to visitors | Invisible by default | Image challenges possible in all tiers |
| Cookies | None | _GRECAPTCHA (necessary cookie) |
| Transferred size (gzip) | 48.9 KB | v2: 423 KB · v3: 459 KB |
reCAPTCHA details from Google’s official documentation (cloud.google.com/recaptcha), checked on Oct 4, 2026. Transferred size: our own measurement of Sep 4, 2026 (SilentShield: Sep 23, 2026). Method and individual values
How SilentShield works on WordPress
SilentShield replaces reCAPTCHA with an invisible check that runs in the background while a visitor fills out a form. The WordPress plugin adds the client script to your pages and verifies each submission through a single API key. There are no image puzzles, no cookies and no tracking scripts, so your pages stay fast and privacy-friendly.
Which form plugins are tested
After activation, you choose under “SilentShield → Forms” which form plugins are protected; the overview above shows which ones we tested. The plugin recognises Gravity Forms and Ninja Forms, but we have not tested them fully, so switch protection on there only after you have tested it yourself. Your forms and design stay as they are; only when a result is unclear does a visitor see a short calculation task.
Setup with the plugin
Install the plugin from the WordPress plugin directory and activate it. Open “SilentShield → API / SilentShield”, paste your key, click “Validate”, switch on “Activate API” and save. Under “SilentShield → Forms” you choose the forms. From then on every submission of these forms is verified on the server.
Privacy and accessibility by default
SilentShield stores no cookies and uses no cross-site tracking; the IP address is used only for the check and is not stored in plain text. This lets you protect your forms in a GDPR-compliant way. Data is processed on our servers in Germany by default. Because there are no visual or audio puzzles, the protection meets WCAG 2.1 AA and remains usable for keyboard and screen-reader users.
Protect WordPress Now
Install the plugin, enter your key, done. Start for free.
Frequently asked questions
How do I add a CAPTCHA to WordPress?
Install the SilentShield WordPress plugin, paste your API key, and switch on protection under “SilentShield → Forms” for the form plugins you use. The plugin is tested for Contact Form 7, Fluent Forms, WordPress comments, WordPress login, WordPress registration, WooCommerce checkout (classic), WPForms, WooCommerce checkout (block checkout), Elementor Forms, and Avada Forms (checked on October 7, 2026 with plugin 2.15.14 and WordPress 7.1.2). There are no image puzzles or checkboxes — visitors are checked in the background through behavioral signals.
Which WordPress form plugins does SilentShield support?
The plugin was tested with Contact Form 7, Fluent Forms, WordPress comments, WordPress login, WordPress registration, WooCommerce checkout (classic), WPForms, WooCommerce checkout (block checkout), Elementor Forms, and Avada Forms (checked on October 7, 2026 with plugin 2.15.14 and WordPress 7.1.2). Other form plugins are recognised by the plugin, but not fully tested — switch protection on there only after you have tested it yourself. You install the plugin once, add your API key and switch on the forms under “SilentShield → Forms”; there is no visible CAPTCHA widget.
Is the SilentShield WordPress plugin GDPR-compliant?
Yes. Like every SilentShield plan, the protection keeps data on our servers in Germany, sets no cookies, does no cross-site tracking and stores the IP address only as a hash. Whether you need consent depends on the mode: in Zero-PII mode the widget does without fingerprint characteristics (canvas, WebGL, audio). reCAPTCHA, by contrast, loads scripts from Google.
Does the WordPress CAPTCHA slow down my site?
Hardly. The plugin loads a client script of about 49 KB (gzip, measured on 23 Sep 2026) with no image assets. Verification happens through behavioural signals and a proof-of-work nonce with no third-party tracking calls.
Do WordPress users have to solve a puzzle?
Not in the default mode. The plugin embeds the SilentShield widget, which verifies real users in the background through behavioural signals and a proof-of-work nonce; only when the result is unclear is there a short arithmetic task. The widget is tested against WCAG 2.1 AA.
How much does the WordPress CAPTCHA cost?
SilentShield has a free tier and paid tiers, and the WordPress plugin works on every plan with a single API key. The free tier includes invisible protection, servers in Germany, no cookies and the IP address only as a hash; paid tiers are for higher request volumes.