为了更好地控制您应用的登录体验，您可以实现自己的身份验证流程，并使用 Firebase SDK 来处理 Firebase 的身份验证服务。例如，您可以构建自己的电子邮件地址和密码流程或 Google 登录流程，并将用户的电子邮件地址和密码或 Google ID 令牌传递给 Firebase，以对用户进行身份验证。
[[["易于理解","easyToUnderstand","thumb-up"],["解决了我的问题","solvedMyProblem","thumb-up"],["其他","otherUp","thumb-up"]],[["没有我需要的信息","missingTheInformationINeed","thumb-down"],["太复杂/步骤太多","tooComplicatedTooManySteps","thumb-down"],["内容需要更新","outOfDate","thumb-down"],["翻译问题","translationIssue","thumb-down"],["示例/代码问题","samplesCodeIssue","thumb-down"],["其他","otherDown","thumb-down"]],["最后更新时间 (UTC)：2025-09-04。"],[],[],null,["I already have an authentication system\n\nIf your app already has a sign-in implementation and you want to use it to\nauthenticate with Firebase backend services, use **Custom Authentication**. This\nincludes apps that use any of the following:\n\n- Custom-built solutions, such as custom password-based systems.\n- Third-party identity management services, such as Auth0 or Okta.\n- Existing integrations with federated identity providers, such as Google, Facebook, or Apple. (And if you don't yet support federated identity, but you want to, see the next section.)\n\nWith custom authentication, you sign users in with the system of your choice,\ncreate a Firebase token for the user on your backend, and then use the token\nfrom the client to authenticate with Firebase.\n\nSee the docs for\n[iOS+](/docs/auth/ios/custom-auth),\n[Android](/docs/auth/android/custom-auth),\n[Web](/docs/auth/web/custom-auth),\n[Flutter](/docs/auth/flutter/custom-auth),\n[Unity](/docs/auth/unity/custom-auth), or\n[C++](/docs/auth/cpp/custom-auth).\n\nI want to build my authentication system with Firebase\n\nIf you're building a new app or adding sign-in to an existing app, Firebase has\nlibraries and services that can help you implement secure authentication without\nhaving to build the authentication backend yourself. Firebase Authentication is a\ncomplete backend solution for signing in with passwords, federated identity\nproviders, email links, and text messages.\n\nI want a drop-in solution that's easy to use\n\nThe fastest and easiest way to add authentication to an app is to use\n**FirebaseUI Auth** , a drop-in UI library. FirebaseUI implements complete user\nflows for all of Firebase Authentication's supported sign-in methods.\n\nBecause FirebaseUI Auth is a drop-in solution, it has a specific UX that might\nnot meet your needs. If you want to change the UX, you can fork the library,\nwhich is open source, and use your own version. However, for substantially\ndifferent sign-in flows, you might prefer to implement your own flows with the\nFirebase SDK as discussed in the next section.\n\nSee the FirebaseUI Auth docs for\n[iOS](/docs/auth/ios/firebaseui),\n[Android](/docs/auth/android/firebaseui), or\n[Web](/docs/auth/web/firebaseui).\n\nI want full control over the sign-in experience\n\nFor more control over your app's sign-in experience, you can implement your own\nauthentication flows and use the Firebase SDK to work with Firebase's\nauthentication services. For example, build your own email address and password\nflow or Google Sign-in flow, and pass the user's email address and password or\nGoogle ID token to Firebase to authenticate the user.\n\nSee the Firebase Authentication SDK docs:\n\n| Firebase services ||\n|----------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|\n| **Email address and password sign-in** | [iOS+](/docs/auth/ios/password-auth) \\| [Android](/docs/auth/android/password-auth) \\| [Web](/docs/auth/web/password-auth) \\| [Flutter](/docs/auth/flutter/password-auth) \\| [Unity](/docs/auth/unity/password-auth) \\| [C++](/docs/auth/cpp/password-auth) |\n| **Phone number sign-in** | [iOS+](/docs/auth/ios/phone-auth) \\| [Android](/docs/auth/android/phone-auth) \\| [Web](/docs/auth/web/phone-auth) \\| [Flutter](/docs/auth/flutter/phone-auth) \\| [Unity](/docs/auth/unity/phone-auth) \\| [C++](/docs/auth/cpp/phone-auth) |\n| **Email link sign-in** | [iOS+](/docs/auth/ios/email-link-auth) \\| [Android](/docs/auth/android/email-link-auth) \\| [Web](/docs/auth/web/email-link-auth) \\| [Flutter](/docs/auth/flutter/email-link-auth) \\| [Unity](/docs/auth/unity/email-link-auth) \\| [C++](/docs/auth/cpp/email-link-auth) |\n| **Google** | [iOS+](/docs/auth/ios/google-signin) \\| [Android](/docs/auth/android/google-signin) \\| [Web](/docs/auth/web/google-signin) \\| [Flutter](/docs/auth/flutter/federated-auth#google) \\| [Unity](/docs/auth/unity/google-signin) \\| [C++](/docs/auth/cpp/google-signin) |\n| **Facebook** | [iOS+](/docs/auth/ios/facebook-login) \\| [Android](/docs/auth/android/facebook-login) \\| [Web](/docs/auth/web/facebook-login) \\| [Flutter](/docs/auth/flutter/federated-auth#facebook) \\| [Unity](/docs/auth/unity/facebook-login) \\| [C++](/docs/auth/cpp/facebook-login) |\n| **Apple** | [iOS+](/docs/auth/ios/apple) \\| [Android](/docs/auth/android/apple) \\| [Web](/docs/auth/web/apple) \\| [Flutter](/docs/auth/flutter/federated-auth#apple) \\| [Unity](/docs/auth/unity/apple) \\| [C++](/docs/auth/cpp/apple) |\n| **Play Games** | [Android](/docs/auth/android/play-games) \\| [Unity](/docs/auth/unity/play-games) \\| [C++](/docs/auth/cpp/play-games) |\n| **Game Center** | [iOS+](/docs/auth/ios/game-center) |\n| **GitHub** | [iOS+](/docs/auth/ios/github-auth) \\| [Android](/docs/auth/android/github-auth) \\| [Web](/docs/auth/web/github-auth) \\| [Flutter](/docs/auth/flutter/federated-auth#github) \\| [Unity](/docs/auth/unity/github-auth) \\| [C++](/docs/auth/cpp/github-auth) |\n| **Microsoft** | [iOS+](/docs/auth/ios/microsoft-oauth) \\| [Android](/docs/auth/android/microsoft-oauth) \\| [Web](/docs/auth/web/microsoft-oauth) \\| [Unity](/docs/auth/unity/microsoft-oauth) \\| [C++](/docs/auth/cpp/microsoft-oauth) |\n| **Twitter** | [iOS+](/docs/auth/ios/twitter-login) \\| [Android](/docs/auth/android/twitter-login) \\| [Web](/docs/auth/web/twitter-login) \\| [Flutter](/docs/auth/flutter/federated-auth#twitter) \\| [Unity](/docs/auth/unity/twitter-login) \\| [C++](/docs/auth/cpp/twitter-login) |\n| **Yahoo** | [iOS+](/docs/auth/ios/yahoo-oauth) \\| [Android](/docs/auth/android/yahoo-oauth) \\| [Web](/docs/auth/web/yahoo-oauth) \\| [Unity](/docs/auth/unity/yahoo-oauth) \\| [C++](/docs/auth/cpp/yahoo-oauth) |\n\nI want to build rich pre-sign-in experiences\n\nYou can enable users to use the signed-in features of your app before they\nactually sign in using **Anonymous Auth**. With anonymous \"sign-in\", you create\ntemporary single-session accounts, which you can use like a real account. Then,\nafter the user signs in or signs up, link the temporary account to the real\naccount to let them continue where they left off.\n\nAnonymous Auth works well alongside either Custom Auth or any of Firebase's\nauthentication services.\n\nSee the docs for\n[iOS+](/docs/auth/ios/anonymous-auth),\n[Android](/docs/auth/android/anonymous-auth),\n[Web](/docs/auth/web/anonymous-auth),\n[Flutter](/docs/auth/flutter/anonymous-auth),\n[Unity](/docs/auth/unity/anonymous-auth), or\n[C++](/docs/auth/cpp/anonymous-auth).\n\nI want to access Firebase services from my backend\n\nTo access Firebase services from a server, you don't need to use\nFirebase Authentication. Instead, use the [Admin SDK](/docs/admin/setup). When you\ninitialize the Admin SDK, you authenticate with service account credentials,\nwhich represent your Firebase project rather than a particular user, and which\ngrant full access to your project's resources."]]
