Your defense against traffic spikes

Private Captcha automatically adjusts challenge difficulty and, as request volume rises, naturally distributes traffic over time.

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server load

Direct traffic

With Private Captcha

time

How automatic difficulty scaling works

Challenges with higher difficulty require exponentially more resources to complete, quickly exhausting bots' capabilities.

Starts with Easy

Difficulty of every challenge is determined based on usage patterns either by bots or by real users.

Goes to Hard (and beyond)

Frequently Asked Questions

How does Private Captcha technology work?

Instead of asking users to solve complex puzzles or track their behavior, Private Captcha solves an invisible cryptographic task in the background. The system automatically adjusts the task difficulty, ensuring smooth access for real users while making it too costly for bots to attempt. Cryptographic task provides equal security regardless of bot's intelligence level, making it effective even as AI technology improves. Which is hard to say about image/sound recognition tasks of other captchas.

How does Private Captcha tell bots and users apart?

On scale, bots exhibit different usage patterns and fingerprints statistics than real users. Detection of those patterns is part of the Private Captcha solution.

How Private Captcha is different from other Proof-of-Work solutions?

Unlike other solutions, that only have client-side code open, Private Captcha's backend code is also publicly available, making it easy to verify how user data is handled. Additionally, you can host Private Captcha on premises inside your own organization.

How do I add Private Captcha on my website?

Private Captcha comes with many pre-built integrations for popular online platforms, such as WordPress, and packages for many popular programming languages (Javascript, Python, etc.). Additionally, our documentation provides detailed setup and migration guides and integration examples.

Can I customize how the Private Captcha widget looks like?

The Private Captcha widget offers two color themes (light and dark) and also allows to do lower-level customization, using CSS, ensuring seamless integration with your website. Additionally, you can hide the captcha widget altogether and make your custom UI integration, all while keeping security benefits.

Integrate in minutes

Ready integrations

Works with most popular platforms and frameworks

Copy the code

Plug-and-play, customizable widget code

<form>
  <div class="private-captcha" data-sitekey="xyz"
    data-started-callback="your-callback"
    data-finished-callback="your-callback"
  </div>
</form>

Extensive documentation for developers

Popular use-cases, copy-paste examples and detailed API specifications

Real human support

We strive to address all support requests within 24 business hours. No AI chatbots.

Compare with others

User-friendly
Humans don’t need to prove they’re human
GDPR-compliant
Self-hosting
Difficulty scaling
The more bots try, the harder it gets
EU-only endpoints
Real Human support
No AI chatbots ever

Google reCAPTCHA

Grey area (at best)

Private Captcha

CloudFlare Turnstile

Quite likely
Enterprise tier only

Protect your forms and APIs from abuse

Independent, privacy-first, self-hostable CAPTCHA service made in EU