Castle vs. EventSend 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 a browser-layer security platform that gives you visibility for every visitor, human or agentic. Security, fraud prevention, privacy and compliance, all from a single script. Unlike traditional WAFs and server-side security tools, cside operates directly in the browser environment, monitoring every third-party script loaded on your pages in real time. This means threats that bypass your backend defences are caught at the point of execution. What cside does: Script Monitoring and Control: cside inventories, monitors, and enforces policy on every third-party JavaScript tag running on your site. 100% session coverage, no sampling. Every script. Every page load. Detect supply chain attacks, shadow scripts, and unauthorised tag injections before they reach your customers. PCI DSS 4.0.1 Compliance: cside is the fastest path to meeting PCI DSS 4.0.1 requirements 6.4.3 and 11.6.1. Automated script authorisation, tamper detection, and continuous monitoring satisfy QSA requirements without manual effort. Validated by VikingCloud. Device Intelligence: Persistent, privacy-safe device intelligence using 102+ signals and 40+ hashed attributes. 99.7% fingerprint accuracy enables fraud prevention, bot detection, and session continuity across logins, checkouts, and account actions. AI Agent and Bot Detection: Identify and classify AI crawlers, headless browsers, and automated agents interacting with your site. Protect pricing data, inventory, and content from scraping and abuse. Chargeback Evidence: Capture cryptographically verifiable session evidence at checkout to dispute fraudulent chargebacks. Reduce dispute losses without adding friction to genuine customers. Who uses cside: E-commerce retailers, payment service providers, digital agencies, travel and hospitality platforms, iGaming and betting operators, financial services firms, and SaaS companies managing PCI compliance, fraud risk, and client-side attack surface across high-traffic web environments. Deployment: One-line script tag. No proxy. No latency impact. Up and running in under 5 minutes. SOC 2 Type II certified. PCI SAQ-D validated.

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.

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.

Sumsub is the world's first AI-powered trust infrastructure platform for compliance operations at scale. By bringing together identity and business verification, fraud prevention, ongoing monitoring, and risk management in a single platform, Sumsub helps businesses simplify compliance, adapt to evolving regulations, expand into new markets, and grow with confidence. As trust becomes a continuous process, organizations need every verification, risk signal, workflow, and decision to work together. Sumsub replaces fragmented compliance tools with unified monitoring and decisioning, helping businesses strengthen security, improve efficiency, and scale operations without increasing complexity or headcount. Powered by Summy AI, AI-driven decisioning, and MCP connectivity, the platform enables teams to automate compliance workflows, accelerate investigations, reduce manual work, and respond faster to regulatory and business changes. Built for digital businesses and highly regulated industries, Sumsub serves organizations across financial services, banking, fintech, crypto, mobility, trading, marketplaces, education, and iGaming. Operating in more than 220 countries and territories, the platform helps companies localize onboarding, meet regional compliance requirements, and adapt workflows for different customer segments, jurisdictions, and risk profiles without extensive redevelopment. Trusted by more than 4,000 organizations worldwide, Sumsub's customers include Bybit, Bitpanda, Wirex, Avis, Vodafone, Duolingo, Kaizen Gaming, and Bancaribe. The company has been recognized as a Leader by Gartner, Forrester, IDC, Liminal, and KuppingerCole for its innovation in digital trust and compliance. Sumsub also contributes to the global fight against fraud and financial crime by collaborating with organizations including the UN, Statista, and INTERPOL. Its original research, including the Global Fraud Index and Fraud Report, provides insights into emerging fraud and AML trends for businesses, regulators, and financial institutions. Since 2026, Sumsub has been a member of the World Economic Forum's Unicorn Community and its Centre for Financial and Monetary Systems.

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.

EventsAir is a comprehensive, all-in-one event management platform. With over 30 years of expertise, EventsAir has powered 350,000+ successful, complex events, earning the trust of the industry's best to deliver seamless, standout experiences. Our feature-packed, cloud-based platform provides all the tools and technology event planners need to execute engaging in-person, virtual, and hybrid events from start to finish.  Flexibility is at the heart of EventsAir's design, ensuring it scales and transforms effortlessly to cater to the diverse needs of events, delivering an experience that's tailor-made for everyone involved. From built-in budgeting and accounting tools to breathtaking on-brand event sites, seamless registration experiences, and even mobile event apps that can be published in minutes, EventsAir truly makes event planning a breath of fresh...air.   At EventsAir, we stand as a dedicated technology partner.