Castle

Prevent Fraud. Not Customers.

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Overview

Castle provides a platform to protect online businesses from account takeover, fake account creation, and other forms of abuse. It works by monitoring user behavior across devices and sessions, using device fingerprinting and behavioral analytics to calculate a real-time risk score for each login and action. This allows businesses to challenge high-risk users with MFA while providing a frictionless experience for legitimate customers.

✨ Key Features

  • Device Fingerprinting
  • Behavioral Analytics
  • Risk-based Authentication
  • Account Takeover (ATO) Prevention
  • Bot Detection
  • Customizable Policies
  • Threat Intelligence Feed

🎯 Key Differentiators

  • Developer-friendly API and documentation
  • Focus on adaptive, risk-based authentication rather than just blocking
  • Generous free tier for startups

Unique Value: Enables businesses to secure user accounts from takeover without adding friction for legitimate users, by dynamically adjusting security based on real-time risk.

🎯 Use Cases (5)

Account takeover prevention Credential stuffing protection Fake account registration Risk-based multi-factor authentication (MFA) Bot detection

✅ Best For

  • Securing customer login flows
  • Preventing automated account creation

💡 Check With Vendor

Verify these considerations match your specific requirements:

  • Payment fraud detection (less focus than competitors)

🏆 Alternatives

Sift Auth0 Okta HUMAN Security

Provides a more focused and developer-friendly solution for account security compared to broader fraud platforms, and offers more advanced risk signals than traditional identity providers.

💻 Platforms

Web iOS Android API

🔌 Integrations

Auth0 Okta Segment Twilio SendGrid API Webhooks

🛟 Support Options

  • ✓ Email Support
  • ✓ Live Chat
  • ✓ Dedicated Support (Enterprise tier)

🔒 Compliance & Security

✓ SOC 2 ✓ GDPR ✓ SSO ✓ SOC 2 Type II ✓ GDPR ✓ CCPA

💰 Pricing

Contact for pricing
Free Tier Available

✓ 30-day free trial

Free tier: Up to 10,000 Monthly Active Users (MAU)

Visit Castle Website →