Security platform that detects bots, account takeover and in-app fraud using device, email, IP and behavioral signals.
Castle is a security platform for product and engineering teams that need to stop bots, account abuse and in-app fraud. It combines device fingerprinting, IP and email intelligence, behavioral analysis and AI scoring to flag account takeover, credential stuffing, fake signups and automated traffic. A rules engine lets teams allow, challenge or deny requests in real time, while analytics, pattern exploration and session monitoring support investigation. It is sold as a hosted service with SDKs and APIs, and the site offers a free start option alongside paid plans.
Free
$200/mo
Customcontact sales
Prices in USD, as shown by castle.io. Source: pricing page. Last checked October 30, 2026.
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I want to decide whether Castle (castle.io) is the right tool and which plan to pick. Below is what the StableMRR pricing directory read from Castle's own pricing page (last checked 2026-10-30). It can be out of date, so treat it as a starting point. Category: Developer tools / Auth and identity What it does: Security platform that detects bots, account takeover and in-app fraud using device, email, IP and behavioral signals. Plans: - Free: Free. Limits: Included API usage $5 / mo, IP lookups 5,000, Risk API calls 1,000, Data retention 3 days, Seats 3, Environments 1. Includes: All core features, Real-time API, Scores and API data, IP Intelligence single and batch lookup, Custom Signals and Metrics - Pro: $200/mo. Limits: Included API usage $200 / mo, IP lookups 200,000, Risk API calls 40,000, Data retention 7 days, Seats 5, Environments 2. Includes: Everything in Free, Higher rate limits, Chat and email support, Custom Signals and Metrics, Policies, lists, webhooks - Enterprise: Contact sales. Limits: Data retention Up to 18 months, Seats Unlimited, Environments Unlimited, API requests per second Unlimited. Includes: Everything in Pro, No rate limits, Dedicated Slack channel and SLA, Querying API, Full IP database downloads Alternatives in the directory: Aserto, Auth0, Locker, 1Password Pricing page: https://castle.io/pricing/ Directory listing: https://stablemrr.com/p/castle-io First ask me three short questions about my team size, budget and what I need it for. Then recommend one plan, tell me what could make it a bad fit, and compare it with the alternatives. Finish with what I should check on the vendor's site before I pay.
No price changes recorded since we started tracking on October 30, 2026.
| Product | Category | Free plan | Paid from | Plans | Checked |
|---|---|---|---|---|---|
| AsertoCloud-native authorization service that adds fine-grained RBAC, ABAC, and ACL controls to applications and APIs. | Auth and identity | Yes | $0.20/mo | 4 | Oct 29, 2026 |
| Auth0Authentication and authorization platform for adding secure login, user management and access control to apps and AI agents. | Auth and identity | Yes | $35/mo | 4 | Oct 29, 2026 |
| LockerPassword and secrets manager that stores, syncs and shares credentials with end-to-end and zero-knowledge encryption. | Auth and identity | Yes | $1.67/mo | 3 | Oct 29, 2026 |
| 1PasswordPassword manager and access management platform for storing credentials, secrets, and controlling access for people and AI agents. | Auth and identity | - | - | - | - |
| 2FA AuthenticatorBrowser extension that generates two-factor authentication codes and keeps secret keys on the user's device. | Auth and identity | - | - | - | - |
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How this page was made. Plans and prices are read automatically from castle.io's public pricing page, checked against the page text, and re-checked about every week. Method. Something wrong? Tell us.
