Castle vs. Zenlogin Comparison Chart

Auth0 takes a modern approach to Identity, providing secure access to any application, for any user. Safeguarding billions of login transactions each month, Auth0 delivers convenience, privacy, and security so customers can focus on innovation. Auth0 is part of Okta, The World’s Identity Company™. Auth0 lets you quickly integrate authentication and authorization for web, mobile, and legacy applications, with new Fine Grained Authorization (FGA) that goes beyond role-based access control. Authenticate users across all applications with a customized, secure, and standards-based single login. Universal Login connects users to a central authorization server. Credentials aren’t transferred across sources, which boosts security and protects against phishing and credential stuffing attacks. OAuth 2.0 recommends that only external user agents (like the browser) be used by native applications for authentication flows. Auth0’s Universal Login achieves this while enabling SSO.

FusionAuth is a modern, developer-focused identity and access management platform built to give you full control over your authentication stack. Whether you’re building a startup app or managing enterprise-scale infrastructure, FusionAuth delivers all the must-have features — from login and SSO to advanced protocols like OAuth2, OIDC, SAML, and WebAuthn — in a self-hostable or cloud-native package. Designed with developers in mind, FusionAuth integrates seamlessly with any language, framework, or architecture. Every capability is API-first and built for extensibility, so you can tailor authentication workflows without getting locked into rigid, inflexible systems. FusionAuth supports all the key use cases — user registration, multi-factor authentication (MFA), passwordless login, role-based access control, and more — while helping you stay compliant with GDPR, HIPAA, PCI, and other regulatory standards.

cside is the leading client-side intelligence platform. Protecting organizations from advanced client-side threats such as script injection, data skimming, and browser-based attacks, risks often overlooked by traditional security measures. Leveraging client-side intelligence to provide evidence to fight chargeback fraud cases. It also addresses the growing challenge of web supply chain risk, ensuring real-time visibility and control over third-party scripts running in user environments. cside provides proactive protection that helps organizations meet compliance requirements like PCI DSS 4.0.1, safeguard sensitive data, and uphold user privacy, all without compromising performance.

Uniqkey: Protect every login. Access with confidence. Uniqkey is Europe’s trusted password and access management platform - purpose-built for companies that demand security, simplicity, and control. Engineered by European cybersecurity experts, our platform combines military-grade encryption with an effortless user experience. We remove complexity from everyday workflows, helping employees stay secure without slowing them down. From auto-filling 2FA codes to streamlining access across your cloud environment, Uniqkey keeps security frictionless and productivity high. With real-time visibility across your entire infrastructure, IT teams gain complete control over access rights, employee activity, and security scores - empowering them to defend against threats and drive compliance with confidence proactively. Seamlessly integrated with Microsoft and other core systems, Uniqkey makes provisioning and offboarding fast, automated, and secure.

Cloudflare is the foundation for your infrastructure, applications, and teams. Cloudflare secures and ensures the reliability of your external-facing resources such as websites, APIs, and applications. It protects your internal resources such as behind-the-firewall applications, teams, and devices. And it is your platform for developing globally scalable applications. Your website, APIs, and applications are your key channels for doing business with your customers and suppliers. As more and more shift online, ensuring these resources are secure, performant and reliable is a business imperative. Cloudflare for Infrastructure is a complete solution to enable this for anything connected to the Internet. Behind-the-firewall applications and devices are foundational to the work of your internal teams. The recent surge in remote work is testing the limits of many organizations’ VPN and other hardware solutions.

Sumsub is a full-cycle verification platform that secures every step of the user journey. With Sumsub’s customizable KYC, KYB, AML, Transaction Monitoring and Fraud Prevention solutions, you can orchestrate your verification process, welcome more customers worldwide, meet compliance requirements, reduce costs and protect your business. Sumsub achieves the highest conversion rates in the industry—91.64% in the US, 95.86% in the UK, and 97.89% in Hong Kong—while verifying users in less than 50 seconds on average. Sumsub’s methodology follows FATF recommendations, the international standard for AML/CTF rules and local regulatory requirements (FINMA, FCA, CySEC, MAS, BaFin). Sumsub has over 2,000 clients across the fintech, crypto, transportation, trading, e-commerce and gaming industries including Bitpanda, Wirex, Avis, Bybit, Huobi, Kaizen Gaming, and TransferGo.

Fraudnet's AI-driven platform empowers enterprises to prevent threats, streamline compliance, and manage risk in real-time. Our sophisticated machine learning models continuously learn from billions of transactions to identify anomalies and predict fraud attacks. Our unified solutions: comprehensive screening for smoother onboarding & improved compliance, continuous monitoring to proactively identify new threats, & precision fraud detection across channels and payment types. With dozens of data integrations and advanced analytics, you'll dramatically reduce false positives while gaining unmatched visibility. And, with no-code/low-code integration, our solution scales effortlessly as you grow. The results speak volumes: Leading payments companies, financial institutions, innovative fintechs, and commerce brands trust us worldwide—and they're seeing dramatic results: 80% reduction in fraud losses and 97% fewer false positives. Request your demo today and discover Fraudnet.

Trumba is an event calendar and registration platform for your website or intranet. Manage all your event data in one place and publish custom calendars for your end users. Trumba currently powers the event calendars for large organizations and small businesses worldwide. Features include: • Customizable and unlimited calendars to cater to multiple audiences or business units. • Integration with 3rd party calendars to manage and publish all events in one place. • Flexible event management with custom templates and role-based editor access. • Event registration with custom forms and payment gateway support. • Attendee management including automated wait listing. • HIPAA-compliant solution for hospitals and healthcare organizations. • SSO support for user and visitor management. • Automated reminders and follow-ups, calendar syncing and personalized event lists. • Integration services and ongoing support included. • And so much more.... Get a demo or free trial today.

Greenhouse is more than an ATS – they’re a true hiring partner that gives companies of all sizes everything they’ll ever need to get measurably better at hiring. With Greenhouse, organizations can cut recruiting costs and ensure every hire is the right hire. Their industry-leading, AI-powered software supports every stage of the hiring process, from sourcing to onboarding, empowering companies to hire top talent quickly, consistently and fairly – today and as their business grows. With a structured hiring approach at its core, Greenhouse makes it easy to define the role, requirements and attributes of a successful candidate before a job is posted, enabling internal alignment and more confident, data-driven decisions. Greenhouse Real Talent™ enhances this process by helping teams identify and prioritize real, qualified candidates while detecting fraud, spam and impersonation attempts.

Regpack is an online registration and payment platform built for programs, not subscriptions. It centralizes enrollment, data collection, and payments in a single system, so you can manage participants, streamline operations, and eliminate manual processes. Used by camps, courses, afterschool programs, and multi-program organizations, Regpack connects registration forms, payment workflows, and reporting in a way subscription billing tools can't. Instead of forcing your process into recurring billing logic, Regpack is designed to reflect how programs actually operate, from first sign-up through final payment. With features like customizable registration flows, flexible payment plans, automated invoicing and reminders, and real-time reporting, Regpack gives you full visibility into your enrollment and revenue. Whether you are running a single program or managing multiple sessions and locations, everything stays connected in one place.