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Fraud Detection Software · Rank #10 of 10

Castle review and pricing

Developer-friendly security + fraud APIs for product engineering teams.

By Castle.io, Inc. · Founded 2014 · San Francisco, CA · private

Castle is the developer-friendly security and fraud platform, founded 2014. The product covers device fingerprinting, behavioral biometrics, account takeover detection, registration fraud, and risk-based authentication via clean APIs and SDKs. Strengths: clean developer experience (API-first, well-documented SDKs), affordable pricing relative to Sift / Sardine for early-stage and mid-market, dual security + fraud positioning (works for product security teams as well as risk-ops), and fast time-to-value for engineering-led adoption. Best fit for product engineering teams at SaaS, fintech, and consumer companies (25-1,000 employees) who want fraud detection without a heavy enterprise sales motion. Trade-offs: smaller installed base than Sift / Sardine, e-commerce coverage shallower than Forter / Signifyd / Riskified, no chargeback guarantee model, and AML coverage absent.

Visit Castle Vendor pricing Compare to Arkose Labs
Best for

Product engineering teams at SaaS, fintech, and consumer companies (25-1,000 employees) who want developer-friendly fraud detection without a heavy enterprise sales motion.

Worst for

Enterprise e-commerce wanting chargeback guarantee (Forter / Signifyd / Riskified better), AML-primary fintech (ComplyAdvantage / Sardine better), or buyers who want one-vendor coverage across all surfaces (Sift better).

Vendor Trust Score

Is Castle a trustworthy vendor?

7.8/10
Mixed
Pricing transparency
Published rates; no hidden fees
7.5
Contract fairness
Reasonable terms; no auto-renew traps
8.0
Incident response
How they handle outages and breaches
7.5
Post-acquisition behavior
Customer treatment after M&A or PE
8.0
Executive stability
Leadership churn over 24 months
8.0
Roadmap honesty
Public commitments held
8.0
Trust signal log
  • 2024-09-22
    Founder-led; developer-experience positioning maintained
Vendor Trust is scored independently of product quality. A great product from an unfair vendor still earns a low trust score.
Review Intelligence

What 180 reviews actually say

Synthesized from G2, Capterra, Reddit, Trustpilot. Patterns >15% prevalence shown.

Last synthesized
2026-04-29

Praise patterns

  • Clean developer experience (API-first)
    87% →
  • Affordable pricing relative to Sift
    78% →
  • Dual security + fraud positioning
    64% →

Complaint patterns

  • Smaller installed base
    47% →
  • E-commerce coverage shallower than Forter
    41% →
  • AML coverage absent
    31% →
Sentiment trend (6 months)
83/100 +1 pts
12
01
02
03
04
05
Patterns are extracted from review corpus and human-verified. We surface trends, not anecdotes.
Verified Pricing

What buyers actually pay

124 anonymized deal disclosures · last updated 2026-05-01

Contribute your deal price
Company size Median annual
25-200 employees $14,400
200-1,000 employees $54,000
Verified pricing is crowdsourced from buyers under anonymity guarantees. Vendor-listed prices are validated against actual deals quarterly.
Compliance & Security

Auto-verified certifications

Verified 2026-05-01
SOC 2 Type II
ISO 27001
HIPAA
GDPR
CCPA
PCI DSS
FedRAMP

Editorial: Strengths

  • Clean developer experience (API-first)
  • Affordable pricing relative to Sift / Sardine
  • Dual security + fraud positioning
  • Fast time-to-value for engineering-led adoption
  • Founder-led culture
  • Well-documented SDKs

Editorial: Weaknesses

  • Smaller installed base than Sift / Sardine
  • E-commerce coverage shallower than Forter / Signifyd
  • No chargeback guarantee model
  • AML coverage absent
  • Enterprise sales motion thinner than larger vendors

Key features & integrations

  • +Device fingerprinting
  • +Behavioral biometrics
  • +Account takeover detection
  • +Registration fraud detection
  • +Risk-based authentication
  • +API-first developer experience
  • +50+ integrations
50+ integrations
Auth0OktaClerkStripeSegmentCloudflare
Geography supported
Global; strongest in US, EU
Best fit
25–1,000 employees · Product engineering teams at SaaS, fintech, consumer companies
Editorial deep-dive

Read our full ranking of Fraud Detection Software

Castle ranks #10 in our editorial review of 10 fraud detection software platforms. The deep-dive covers methodology, comparison tables, decision matrix, migration scoring, and FAQs.

Read the full ranking

Closest alternatives in Fraud Detection Software

#9
Arkose Labs
Bot management plus account fraud differentiator.
★ 4.6 opaque
#8
Kount
Legacy fraud platform inside Equifax; broad footprint, slowing innovation.
★ 4.1 opaque
#7
Signifyd
E-commerce fraud with chargeback guarantee for mid-market retailers.
★ 4.5 opaque
Help the next buyer

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