Google's Firebase is an entire app development platform that's packed with features.It comes with storage, cloud functions, monitoring and, of course, user authentication. The free tier comes with 50,000 MAUs. Beyond that pricing start at $0.0055/MAU and goes down to as low as $0.0025/MAU as you scale to millions of users. Firebase authentication supports email and password auth, phone auth, magic links, two-factor authentication and social identity providers - mainly Google, Google Play Games, Facebook, Apple, Microsoft, Twitter, GitHub and OAuth access tokens.

Auth0 is an identity and access management (IAM) platform designed to simplify authentication and authorization for applications. It provides a flexible solution that allows developers to implement secure login systems without having to build them from the ground up. Auth0 supports various authentication methods, including username-password credentials, social logins (like Google, Facebook, and GitHub), enterprise identity providers (such as Active Directory and SAML-based systems), and passwordless options. The platform is highly adaptable, offering over 30 software development kits (SDKs) that cater to a wide range of languages and frameworks—JavaScript, Python, .NET, iOS, Android, and more. This makes integration straightforward regardless of the tech stack. Beyond basic authentication, Auth0 offers advanced features like multi-factor authentication (MFA), single sign-on (SSO), and fine-grained authorization. These tools enable organizations to enforce complex access control policies, supporting both role-based (RBAC) and attribute-based (ABAC) models. Auth0 also addresses enterprise needs through features like user provisioning, directory synchronization, and support for B2B, B2C, and B2E use cases. It’s designed with scalability in mind, making it suitable for both startups and large enterprises. The platform’s extensibility allows developers to customize authentication flows, implement rules for conditional access, and integrate third-party services. Since its acquisition by Okta, Auth0 operates as a product unit under the Okta umbrella, complementing Okta’s broader suite of identity solutions while maintaining a developer-first focus. This combination brings together Okta’s enterprise-grade security with Auth0’s developer-centric approach, offering a comprehensive solution for modern identity challenges.

Clerk is a comprehensive user management and authentication platform designed to streamline how developers handle user accounts within web and mobile applications. It offers a suite of embeddable UI components—such as <SignIn/>, <SignUp/>, <UserButton/>, and <UserProfile/>—that integrate seamlessly into your application without redirecting users off-site. These components are fully customizable to match your brand, making the user experience cohesive and frictionless. Under the hood, Clerk provides a robust API and SDKs compatible with modern frameworks like Next.js, Remix, React, and Expo. It handles the entire authentication lifecycle, supporting multifactor authentication (MFA), session management, passwordless sign-in (via magic links or one-time passcodes), and traditional password-based methods with breach detection. The platform also integrates social sign-on (SSO) with over 20 providers, enabling quick user onboarding while adhering to security best practices. Clerk’s security posture includes SOC 2 Type 2 certification and CCPA compliance, with continuous third-party audits and penetration testing. Fraud prevention measures, like disposable email blocking and bot detection powered by machine learning, are built-in to reduce spam and abusive sign-ups. For B2B SaaS applications, Clerk provides advanced multi-tenancy features, enabling organization-based user management with custom roles, permissions, auto-join functionality based on email domains, and invitation systems—all accessible through both code and an admin dashboard. Developers benefit from rapid integration, significantly reducing the time spent on building authentication systems from scratch. Clerk acts as the single source of truth for user data and integrates seamlessly with popular backend services like Supabase, Firebase, and Convex. With free access for up to 10,000 monthly active users, it’s positioned as a scalable solution that grows with your application’s needs.

Supabase is the open-source alternative to Firebase. Like Firebase, it's a complete app development platform with user authentication, cloud functions, APIs, Postgres database, storage, vector embeddings, and other features. Supabase projects come with PostgreSQL's policy engine for fine-grained user access rules. It has social login integrations with Google, Facebook, GitHub, Azure (Microsoft), Gitlab, Twitter, Discord, and many more. They offer a customizable authentication component for React. Phone login and MFA can be added through third-party SMS providers such as Twilio or Bird. The free tier comes with 50,000 monthly active users. The Pro plan, at $25/month, comes with 100,000 MAUs and $0.00325/MAU beyond that.

Stytch provides a suite of tools designed to simplify authentication, authorization, and security for web and mobile applications. If you're developing an app and need a way for users to log in—whether with passwords, passkeys, or entirely passwordless methods—Stytch offers APIs and SDKs that handle these complexities. Their focus is on making authentication seamless for both developers and end-users while ensuring high security standards. For businesses, particularly B2B SaaS companies, Stytch enables advanced features like multi-tenancy, role-based access control (RBAC), and single sign-on (SSO). They provide an embeddable admin portal, allowing enterprise customers to manage their own authentication configurations, organizational settings, and integrations with identity providers—without constant developer involvement. Stytch places a strong emphasis on scalability and flexibility. Their tools are designed to “just work” across a range of use cases, from simple consumer apps to complex enterprise platforms. Developers can choose how much of the authentication flow they want to control—using pre-built UI components for quick implementation or leveraging headless SDKs and backend APIs for a fully customized experience. Security and fraud prevention are also core to Stytch’s offering. They provide real-time bot detection, device-aware multi-factor authentication, and intelligent rate limiting to protect against credential stuffing and other forms of account abuse. Their infrastructure ensures that login codes and authentication requests are delivered reliably, even when SMS or email providers fail. Stytch supports a broad range of programming languages and frameworks, including Python, Node.js, Java, React, and iOS, making integration into existing tech stacks straightforward. Their platform is designed for developers who want to build secure, user-friendly authentication systems without reinventing the wheel.

Ory is an API-first identity manager. They offer authentication, analytics, access control, machine-to-machine authentication and more. They have SDKs for the major languages: - Dart - .NET - Elixir - Go - Java - JavaScript - PHP - Python - Ruby - Rust Unfortunately, they don't offer a free tier. Pricing starts at $29/month and includes 1,000 daily active users. Then it's $30 / 1,000 additional DAUs.

Appwrite is an open-source platform for building scalable applications. It comes with authentication, databases, storage, and functions. It's basically a complete development platform. They have an extremely generous free plan with 75,000 MAUs free of charge and their Pro plan is only $15/month. Appwrite offers email and password login, phone auth, magic links, email OTP, anonymous login, JWT login, SSR login, custom tokens, and two-factor authentication.

GoPasswordless is an authentication service and SDK that focuses on enabling passwordless authentication flows in web apps.

AISaver is an AI-powered platform offering a range of tools for video and image processing. It integrates features such as video face swap, image face swap, image enhance, video enhance, and text-to-speech conversion. Key Features of AISaver: 1. Video downloader online tool, easily download any video from any platform. 2. Face swap tool, easily swap faces in videos by using our AI Face Swap with a few clicks. Upload videos, then upload photos and then generate an interesting face swap video. 3. All in one video downloading and enhancing software, enhance your videos with powerful AI tools. AISaver is a free online face-swapping tool offering one-click video swaps with realistic effects. Enjoy safe, privacy-protected processing as the AI seamlessly integrates your chosen face into any video for an authentic result without storing personal data. With AI-driven technology, it delivers realistic results and is easy to use, making it an essential site for media processing.

Decopy AI offers a comprehensive platform for detecting AI-generated content in both text and images, as well as verifying the origins of visuals. Key Features 1. AI Content Detector: Identifies whether text is written by AI or humans. 2. AI Image Detector: Detects AI-manipulated images. 3. Reverse Image Search: Finds the original source of an image across the web. Benefits - All of Decopy AI’s powerful detection tools are completely free to use. No subscriptions, no hidden fees—everyone can access and benefit from our AI Content Detector, AI Image Detector, and other tools at zero cost. - AI Detector tools are built on advanced algorithms that provide exceptional accuracy in identifying AI-generated content and images. Whether you’re analyzing text or visuals, Decopy AI delivers reliable results that you can trust. Use Case - Educators verify student submissions for AI-generated work. - Businesses check content authenticity for marketing. - Researchers trace image origins for verification. - Content creators prevent unauthorized use of their visuals.

Lisapet.ai is the next-level AI product development platform that empowers teams to prototype, test, and ship robust AI features 10x faster. Key Features - Best-in-class AI Playground: Swiftly test and iterate your prompts. Reduce the hassle of prompt prototyping. Our best-in-class AI playground makes the workflow faster, saving you time and effort in designing prompts. - Test-driven prompt engineering: Evalute and measure quality across large data sets. Build a collection of test cases to find the best prompt/model combination across different scenarios Benefits - Save Time: Cut down manual testing and free up your team to focus on shipping features. - Increase Confidence: Automate your testing to ensure reliable AI behavior before deployment. - Optimize Performance: Easily identify the best-performing prompts through side-by-side testing and real-time analytics. - Collaborate Seamlessly: Share progress with stakeholders and incorporate feedback directly within the platform. - Reduce Costs: Monitor token usage and optimize spending with detailed cost breakdowns. Use Case - Rapid Development of AI-Powered Features: Equip your product teams with tools to build, test, and launch AI-powered features without bottlenecks. - Scalable Prompt Engineering: Automate testing and validation to save time and reduce errors in prompt design. - Collaborative Testing: Enable cross-team collaboration by sharing reports and integrating feedback seamlessly.

VideoFaceSwap is a cutting-edge tool that leverages advanced technology to enable seamless face-swapping in videos and images, making creative multimedia processing easy and accessible. Key Features - Face swap: High-quality face-swapping for videos and images, including multi-face and batch processing. - Image tools collection: Additional tools like video enhancement, noise reduction, image enhancement, and background removal for comprehensive multimedia editing. Benefits 1. Simplified Editing: Offers an easy-to-use solution for precise, realistic face-swapping without requiring advanced editing skills. 2. Comprehensive Tools: Combines multiple multimedia processing features into one platform, saving time and effort for users. Use Case 1. Content Creation: Enhance social media videos with creative face-swapping effects to boost engagement. 2. Entertainment and Production: Create customized videos for role-playing, movie edits, or promotional campaigns.