import{initializeApp}from"firebase/app";constfirebaseConfig={apiKey:"...",// By default, authDomain is '[YOUR_APP].firebaseapp.com'.// You may replace it with a custom domain.authDomain:'[YOUR_CUSTOM_DOMAIN]'};constfirebaseApp=initializeApp(firebaseConfig);
firebase.initializeApp({apiKey:'...',// By default, authDomain is '[YOUR_APP].firebaseapp.com'.// You may replace it with a custom domain.authDomain:'[YOUR_CUSTOM_DOMAIN]'});
[[["易于理解","easyToUnderstand","thumb-up"],["解决了我的问题","solvedMyProblem","thumb-up"],["其他","otherUp","thumb-up"]],[["很难理解","hardToUnderstand","thumb-down"],["信息或示例代码不正确","incorrectInformationOrSampleCode","thumb-down"],["没有我需要的信息/示例","missingTheInformationSamplesINeed","thumb-down"],["翻译问题","translationIssue","thumb-down"],["其他","otherDown","thumb-down"]],["最后更新时间 (UTC)：2025-08-11。"],[[["\u003cp\u003eThis guide explains how to customize the Identity Platform authentication handler to display your own domain during sign-in instead of the default \u003ccode\u003e[PROJECT-ID].firebaseapp.com\u003c/code\u003e domain.\u003c/p\u003e\n"],["\u003cp\u003eUsing the default domain provides benefits like easier setup and compatibility with providers that only allow one callback URL per app, but it briefly shows the \u003ccode\u003efirebaseapp.com\u003c/code\u003e URL to users.\u003c/p\u003e\n"],["\u003cp\u003eTo customize the handler, you must connect your project to a custom domain, add the custom domain to the list of Authorized Domains, and update the Callback URL with your identity provider to use the new custom domain.\u003c/p\u003e\n"],["\u003cp\u003eAfter customizing the handler, update the \u003ccode\u003eauthDomain\u003c/code\u003e field in your client SDK configuration (Web, Android, iOS) to your custom domain to ensure proper functionality.\u003c/p\u003e\n"],["\u003cp\u003eConfiguring your custom authentication handler is only available through the Firebase Console, and not through Google Cloud CLI or the Google Cloud console.\u003c/p\u003e\n"]]],[],null,["# Showing a custom domain during sign in\n======================================\n\nThis document shows you how to customize the Identity Platform authentication\nhandler so users see your domain when signing in.\n\nUnderstanding the default authentication handler\n------------------------------------------------\n\nWhen you enable Identity Platform for your project, a unique subdomain\npowered by Firebase Hosting is created automatically.\nThe domain takes the form of `https://[PROJECT-ID].firebaseapp.com`.\nBy default, Identity Platform uses this domain to handle all OAuth, OIDC,\nand SAML sign-in redirects.\n\nUsing the default domain has several benefits:\n\n- Easier setup\n\n- Use multiple domains with the same federated providers\n\n- Share a single callback URL across different services and domains\n\n- Works with providers that only support one callback URL per app\n\nThe downside of the default handler is users will briefly see the\n`https://[PROJECT-ID].firebaseapp.com` URL when signing in.\n\nCustomizing the authentication handler\n--------------------------------------\n\nTo override the default handler and provide your own:\n\n1. [Connect your project to a custom domain](https://firebase.google.com/docs/hosting/custom-domain).\n You'll need to complete these steps using the Firebase Console; using\n the Google Cloud CLI or the Google Cloud console is not\n supported.\n\n2. Go to the **Identity Providers** page in the Google Cloud console, and\n select your SAML provider.\n [Go to the Identity Providers page](https://console.cloud.google.com/customer-identity/providers) \n\n3. Add the custom domain to the list of **Authorized Domains**.\n\n4. Update the **Callback URL** with your identity provider to use your custom\n domain instead of the default domain. For example, change\n `https://myproject.firebaseapp.com/__/auth/handler` to\n `https://auth.mycustomdomain.com/__/auth/handler`.\n\n5. Click **Save**.\n\nUpdating your client SDK configuration\n--------------------------------------\n\n### Web\n\nNormally, you can copy the initialization code for the client SDK from the\nGoogle Cloud console. If you customize the authentication handler, you'll\nneed to update the `authDomain` field to your custom domain: \n\n### Web version 9\n\n```javascript\nimport { initializeApp } from \"firebase/app\";\n\nconst firebaseConfig = {\n apiKey: \"...\",\n // By default, authDomain is '[YOUR_APP].firebaseapp.com'.\n // You may replace it with a custom domain.\n authDomain: '[YOUR_CUSTOM_DOMAIN]'\n};\nconst firebaseApp = initializeApp(firebaseConfig);https://github.com/firebase/snippets-web/blob/467eaa165dcbd9b3ab15711e76fa52237ba37f8b/snippets/auth-next/index/auth_init_custom_domain.js#L8-L16\n```\n\n### Web version 8\n\n```javascript\nfirebase.initializeApp({\n apiKey: '...',\n // By default, authDomain is '[YOUR_APP].firebaseapp.com'.\n // You may replace it with a custom domain.\n authDomain: '[YOUR_CUSTOM_DOMAIN]'\n});https://github.com/firebase/snippets-web/blob/467eaa165dcbd9b3ab15711e76fa52237ba37f8b/auth/index.js#L107-L112\n```\n\n### Android and iOS\n\nTo customize the authentication handler, use the following code: \n\n### Java\n\n FirebaseAuth.getInstance().setCustomAuthDomain(\"[YOUR_CUSTOM_DOMAIN]\");\n\n### Kotlin+KTX\n\n Firebase.auth.setCustomAuthDomain(\"[YOUR_CUSTOM_DOMAIN]\")\n\n### Swift\n\n let auth = Auth.auth()\n auth.customAuthDomain = \"[YOUR_CUSTOM_DOMAIN]\"\n\n### Objective-C\n\n FIRAuth *auth = [FIRAuth auth];\n auth.customAuthDomain(\"[YOUR_CUSTOM_DOMAIN]\");"]]
