![\"ESP32](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2021\/11\/ESP32-ESP8266-Firebase-Authentication.jpg?resize=1200%2C675&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\nUpdated 30 April 2025.<\/em><\/p>\n\n\n\n Other Firebase Tutorials with the ESP32 that you might be interested in:<\/p>\n\n\n\n Firebase is Google’s mobile application development platform that helps you build, improve, and grow your app. It has many services used to manage data from any android, IOS, or web application like authentication, realtime database<\/a>, hosting<\/a>, etc. In this tutorial, we’ll focus on the authentication part.<\/p>\n\n\n Follow the next instructions to create a new project on Firebase.<\/p>\n\n\n\n To allow authentication with email and password, first, you need to set authentication methods for your app. <\/p>\n\n\n\n “Most apps need to know the identity of a user. In other words, it takes care of logging in and identifying the users (in this case, the ESP32 or ESP8266). Knowing a user’s identity allows an app to securely save user data in the cloud and provide the same personalized experience across all of the user’s devices.” To learn more about the authentication methods, you can read the documentation<\/a>.<\/p>\n\n\n\n Firebase creates a unique UID for each registered user. The user UID allows us to identify the user and keep track of the user to provide or deny access to the project or the database. There’s also a column that registers the date of the last sign-in. At the moment, it is empty because we haven’t signed in with that user yet.<\/p>\n\n\n\n To interface with your Firebase project using the ESP32 or ESP8266 boards, you need to get your project API key. Follow the next steps to get your project API key.<\/p>\n\n\n\n Now that your Firebase Project is created and you’ve set up the authentication method, you’ll learn to log in with the ESP32 or ESP8266 using the authorized user email and password.<\/p>\n\n\n\n To program the boards, you can use Arduino IDE<\/a>, VS Code with the PlatformIO or pioarduino extensions<\/a>, or other suitable software.<\/p>\n\n\n\n Note: <\/strong> for firebase projects, we recommend using VS Code with the PlatformIO or pioarduino extension because if you want to develop a web application to make the bridge between the ESP and Firebase, VS Code provides all the tools to do that. However, we won’t build the web application in this tutorial, so you can use Arduino IDE.<\/p>\n\n\n\n To use Firebase with the ESP32 and ESP8266, we’ll use the FirebaseClient library<\/a>. This library is compatible with the ESP32, ESP8266, and many other boards.<\/p>\n\n\n\n If you’re using VS Code with the PlatformIO extension, click on the PIO Home<\/strong> icon and then select the Libraries tab<\/strong>. Search for “FirebaseClient<\/strong>“. Select the Firebase Client Library<\/strong> by Mobitz.<\/p>\n\n\n Then, click Add to Project<\/strong> and select the project you’re working on.<\/p>\n\n\n Also, change the monitor speed to 115200 by adding the following line to the platformio.ini<\/span> file of your project:<\/p>\n\n\n\n If you’re using Arduino IDE, follow the next steps to install the library.<\/p>\n\n\n\n Copy the following code to the Arduino IDE or to the main.cpp<\/span> file if you’re using VS Code.<\/p>\n\n\n View raw code<\/a><\/p>\n\n\n\n You need to insert your network credentials, URL database, and project API key for the project to work.<\/p>\n\n\n\n Continue reading to learn how the code works, or skip to the demonstration section<\/a>.<\/p>\n\n\n\n First, include the required libraries. The WiFi.h<\/span> library to connect the ESP32 to the internet (or the ESP8266WiFi.h<\/span> library for the ESP8266 board), the FirebaseClient.h<\/span> and WiFiClientSecure<\/span> libraries to interface the boards with Firebase. We also include the ExampleFunctions.h<\/span> file which is included in the library that comes with some additional functions for this example.<\/p>\n\n\n\n Include your network credentials in the following lines.<\/p>\n\n\n\n Insert your Firebase project API key.<\/p>\n\n\n\n Set the Firebase email user and corresponding password.<\/p>\n\n\n\n The following line creates an authentication object using the project API key, the project user email, and password.<\/p>\n\n\n\n This creates a FirebaseApp<\/span> instance called app<\/span> that refers to the Firebase application.<\/p>\n\n\n\n The following lines set up the asynchronous communication framework for interacting with Firebase’s Realtime Database. Basically, you create an SSL client using the WiFiClientSecure<\/span> library. Then, you instantiate an Asynchronous client called aClient<\/span> that enables secure HTTPS. This will allow you to handle network operations asynchronously.<\/p>\n\n\n\n In the setup()<\/span>, initialize the Serial Monitor and connect the board to your Wi-Fi network.<\/p>\n\n\n\n Configure the SSL Client (different for ESP32 and ESP8266).<\/p>\n\n\n\n The following line initializes the Firebase app with authentication and sets the processData()<\/span> as the callback function for async results (this means that any results from the initializeApp()<\/span> function will be handled on the processData()<\/span> callback function).<\/p>\n\n\n\n The Firebase library we’re using works asynchronously and with callback functions. This means that when an event happens, the corresponding assigned callback functions will run. To keep the Firebase app running, handling authentication and asynchronous tasks, we need to add app.loop()<\/span> at the start of our loop()<\/span> function.<\/p>\n\n\n\n The app.ready()<\/span> command checks if Firebase authentication is complete and ready, so that we can proceed with other Firebase operations (like getting the User UID). We also have a control variable taskComplete<\/span> so that is just runs once to print the user UID.<\/p>\n\n\n\n Then, we can get the user UID with app.getUid()<\/span>. <\/p>\n\n\n\n We also print more information about the app auth token.<\/p>\n\n\n\n After uploading the code, open the Serial Monitor at a baud rate of 115200.<\/p>\n\n\n\n Note<\/strong>: if you’re using VS Code, you need to add the following line to your platformio.ini<\/span> file to change the baud rate. Then, save your file.<\/p>\n\n\n\n Reset your board by pressing the on-board EN\/RST button.<\/p>\n\n\n\n The ESP32\/ESP8266 authenticates successfully and prints information about the user UID and the authentication token.<\/p>\n\n\n Then, go to your Firebase project console to check if it signed in as a user. Go to Authentication<\/strong> > Users<\/strong>. You should have the current date in the Signed<\/strong> In<\/strong> field. Additionally, you’ll see that the User UID matches the UID printed by your ESP board in the Serial Monitor.<\/p>\n\n\n Congratulations! You successfully signed in your ESP32\/ESP8266 board as a user. You can combine this example with one of our previous tutorials to send sensor readings to the database as an authorized user: ESP32: Getting Started with Firebase (Realtime Database)<\/a> or you can follow this project:<\/p>\n\n\n\n In this tutorial, you learned how to set up the ESP32\/ESP8266 board as a user that can access your Firebase project with email and password. This was just a simple example that you can apply to more advanced projects. <\/p>\n\n\n\n Setting up the ESP as a user allows you to identify the user to enable or restrict access to the Firebase Project or to the database or to specific database nodes\u2014allows you to set up database rules.<\/p>\n\n\n\n We have a project that shows how to use this feature to create database rules and to build a web app with login\/logout features to authorize and restrict access to the data. You can check it out on the following link:<\/p>\n\n\n\n If you want to learn more about building a fully-featured Firebase Web App to control and monitor your ESP32 and ESP8266 boards from anywhere, take a look at our eBook:<\/p>\n\n\n\n Other resources that you might find helpful:<\/p>\n\n\n\n In this guide, you’ll learn how to authenticate to Firebase using your ESP32 or ESP8266 board with an email and password, and get the user UID. This is useful for … <\/p>\n\n
What is Firebase?<\/strong><\/h2>\n\n\n\n
![\"Firebase](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2021\/09\/Firebase-Logo.png?resize=750%2C196&quality=100&strip=all&ssl=1\"){kind=logo}
<\/figure><\/div>\n\n\nProject Overview<\/h2>\n\n\n\n
\n
1) Create Firebase Project<\/span><\/h2>\n\n\n\n
\n
![\"Set](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2025\/04\/1-create-firebase-project.png?w=1200&quality=100&strip=all&ssl=1\")
<\/figure><\/li>\n\n\n\n![\"Set](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2025\/04\/2-create-firebase-project-ai-assistance.png?w=1200&quality=100&strip=all&ssl=1\")
<\/figure><\/li>\n\n\n\n![\"Disable](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2025\/04\/3-create-firebase-project.png?w=1200&quality=100&strip=all&ssl=1\")
<\/figure><\/li>\n\n\n\n![\"Firebase](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2025\/04\/5-Firebase-project-ready.png?w=1200&quality=100&strip=all&ssl=1\")
<\/figure>
<\/li>\n\n\n\n![\"Firebase](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2025\/04\/6-Firebase-console-ESP-project.png?w=1200&quality=100&strip=all&ssl=1\")
<\/figure><\/li>\n<\/ol>\n\n\n\n2) Set Authentication Methods<\/h2>\n\n\n\n
\n
![\"Firebase](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2025\/04\/7-set-authentication.png?w=1200&quality=100&strip=all&ssl=1\")
<\/figure><\/li>\n\n\n\n![\"SFirebase](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2025\/04\/8-Firebase-authentication-methods.png?w=1200&quality=100&strip=all&ssl=1\")
<\/figure><\/li>\n\n\n\n![\"Enable](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2025\/04\/9-enable-email-password-firebase.png?w=1200&quality=100&strip=all&ssl=1\")
<\/figure><\/li>\n\n\n\n![\"Firebase](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2025\/04\/10-add-user-email-password-firebase.png?w=1200&quality=100&strip=all&ssl=1\")
<\/figure><\/li>\n\n\n\n![\"Firebase](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2025\/04\/11-add-user-email-pass.png?w=1200&quality=100&strip=all&ssl=1\")
<\/figure><\/li>\n\n\n\n![\"Firebase](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2025\/05\/user-created-in-firebase-esp32.jpg?w=1200&quality=100&strip=all&ssl=1\")
<\/figure><\/li>\n<\/ol>\n\n\n\n3) Get Project API Key<\/h2>\n\n\n\n
\n
![\"Firebase](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2025\/04\/17-project-settings-firebase.png?w=1200&quality=100&strip=all&ssl=1\")
<\/figure><\/li>\n\n\n\n![\"Firebase](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2025\/04\/18-project-api-key-firebase.png?w=1200&quality=100&strip=all&ssl=1\")
<\/figure><\/li>\n<\/ol>\n\n\n\n4) Authentication with ESP32<\/span>\/ESP8266 <\/h2>\n\n\n\n
Installing the FirebaseClient Library<\/h3>\n\n\n\n
Installation – VS Code + PlatformIO<\/h4>\n\n\n\n
![\"Install](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2021\/09\/Install-FirebsaeClient-Library-VS-Code.jpg?resize=750%2C646&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\n![\"Add](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2021\/09\/Add-FirebaseClient-library-to-project-VS-Code.jpg?resize=750%2C341&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\nmonitor_speed = 115200<\/code><\/pre>\n\n\n\nInstallation – Arduino IDE<\/h4>\n\n\n\n
\n
![\"Install](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2021\/09\/install-Firebase-client-arduino-ide.png?resize=790%2C586&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\nESP32<\/span>\/ESP8266 Firebase Authentication Email\/Password (Get User UID)<\/h3>\n\n\n\n
\/*\r\n Rui Santos & Sara Santos - Random Nerd Tutorials\r\n Complete project details at our blog: https:\/\/RandomNerdTutorials.com\/esp32-esp8266-firebase-authentication\/\r\n Based on this example: https:\/\/github.com\/mobizt\/FirebaseClient\/blob\/main\/examples\/App\/AppInitialization\/UserAuth\/UserAuth.ino\r\n*\/\r\n\r\n#include <Arduino.h>\r\n#if defined(ESP32)\r\n include <WiFi.h>\r\n#elif defined(ESP8266)\r\n #include <ESP8266WiFi.h>\r\n#endif\r\n#include <WiFiClientSecure.h>\r\n#include <FirebaseClient.h>\r\n#include "ExampleFunctions.h" \/\/ Provides the functions used in the examples.\r\n\r\n\/\/ Network and Firebase credentials\r\n#define WIFI_SSID "REPLACE_WITH_YOUR_SSID"\r\n#define WIFI_PASSWORD "REPLACE_WITH_YOUR_PASSWORD"\r\n\r\n#define Web_API_KEY "REPLACE_WITH_YOUR_FIREBASE_PROJECT_API_KEY"\r\n\r\n#define USER_EMAIL "REPLACE_WITH_FIREBASE_PROJECT_EMAIL_USER"\r\n#define USER_PASS "REPLACE_WITH_FIREBASE_PROJECT_USER_PASS"\r\n\r\n\/\/ User functions\r\nvoid processData(AsyncResult &aResult);\r\n\r\n\/\/ Authentication\r\nUserAuth user_auth(Web_API_KEY, USER_EMAIL, USER_PASS);\r\n\r\n\/\/ Firebase components\r\nFirebaseApp app;\r\nWiFiClientSecure ssl_client;\r\nusing AsyncClient = AsyncClientClass;\r\nAsyncClient aClient(ssl_client);\r\nAsyncResult dbResult;\r\n\r\nbool taskComplete = false;\r\n\r\nvoid setup(){\r\n Serial.begin(115200);\r\n\r\n \/\/ Connect to Wi-Fi\r\n WiFi.begin(WIFI_SSID, WIFI_PASSWORD);\r\n Serial.print("Connecting to Wi-Fi");\r\n while (WiFi.status() != WL_CONNECTED) {\r\n Serial.print(".");\r\n delay(300);\r\n }\r\n Serial.println();\r\n Serial.print("Connected with IP: ");\r\n Serial.println(WiFi.localIP());\r\n Serial.println();\r\n\r\n \/\/ Configure SSL client\r\n ssl_client.setInsecure();\r\n #if defined(ESP32)\r\n ssl_client.setConnectionTimeout(1000);\r\n ssl_client.setHandshakeTimeout(5);\r\n #elif defined(ESP8266)\r\n ssl_client.setTimeout(1000); \/\/ Set connection timeout\r\n ssl_client.setBufferSizes(4096, 1024); \/\/ Set buffer sizes\r\n #endif\r\n\r\n \/\/ Initialize Firebase\r\n initializeApp(aClient, app, getAuth(user_auth), processData, "\ud83d\udd10 authTask");\r\n}\r\n\r\nvoid loop(){\r\n \/\/ Maintain authentication and async tasks\r\n app.loop();\r\n\r\n \/\/ Check if authentication is ready\r\n if (app.ready() && !taskComplete){\r\n taskComplete = true;\r\n \/\/ Print authentication info\r\n Serial.println("Authentication Information");\r\n Firebase.printf("User UID: %s\\n", app.getUid().c_str());\r\n Firebase.printf("Auth Token: %s\\n", app.getToken().c_str());\r\n Firebase.printf("Refresh Token: %s\\n", app.getRefreshToken().c_str());\r\n print_token_type(app);\r\n }\r\n}\r\n\r\nvoid processData(AsyncResult &aResult){\r\n if (!aResult.isResult())\r\n return;\r\n\r\n if (aResult.isEvent())\r\n Firebase.printf("Event task: %s, msg: %s, code: %d\\n", aResult.uid().c_str(), aResult.eventLog().message().c_str(), aResult.eventLog().code());\r\n\r\n if (aResult.isDebug())\r\n Firebase.printf("Debug task: %s, msg: %s\\n", aResult.uid().c_str(), aResult.debug().c_str());\r\n\r\n if (aResult.isError())\r\n Firebase.printf("Error task: %s, msg: %s, code: %d\\n", aResult.uid().c_str(), aResult.error().message().c_str(), aResult.error().code());\r\n\r\n if (aResult.available())\r\n Firebase.printf("task: %s, payload: %s\\n", aResult.uid().c_str(), aResult.c_str());\r\n}\r\n<\/code><\/pre>\n\tHow the Code Works<\/h3>\n\n\n\n
Include Libraries<\/h4>\n\n\n\n
#include <Arduino.h>\n#if defined(ESP32)\n #include <WiFi.h>\n#elif defined(ESP8266)\n #include <ESP8266WiFi.h>\n#endif\n#include <WiFiClientSecure.h>\n#include <FirebaseClient.h>\n#include \"ExampleFunctions.h\" \/\/ Provides the functions used in the examples.<\/code><\/pre>\n\n\n\nDefining Credentials<\/h4>\n\n\n\n
#define WIFI_SSID \"REPLACE_WITH_YOUR_SSID\"\n#define WIFI_PASSWORD \"REPLACE_WITH_YOUR_PASSWORD\"<\/code><\/pre>\n\n\n\n#define Web_API_KEY \"REPLACE_WITH_YOUR_FIREBASE_PROJECT_API_KEY\"<\/code><\/pre>\n\n\n\n#define USER_EMAIL \"REPLACE_WITH_FIREBASE_PROJECT_EMAIL_USER\"\n#define USER_PASS \"REPLACE_WITH_FIREBASE_PROJECT_USER_PASS\"<\/code><\/pre>\n\n\n\nDeclaring Firebase Authentication and Components<\/h4>\n\n\n\n
UserAuth user_auth(Web_API_KEY, USER_EMAIL, USER_PASS);<\/code><\/pre>\n\n\n\nFirebaseApp app;<\/code><\/pre>\n\n\n\nWiFiClientSecure ssl_client;\nusing AsyncClient = AsyncClientClass;\nAsyncClient aClient(ssl_client);<\/code><\/pre>\n\n\n\nsetup()<\/h4>\n\n\n\n
void setup(){\n Serial.begin(115200);\n WiFi.begin(WIFI_SSID, WIFI_PASSWORD);\n Serial.print(\"Connecting to Wi-Fi\");\n while (WiFi.status() != WL_CONNECTED) {\n Serial.print(\".\");\n delay(300);\n }\n Serial.println();<\/code><\/pre>\n\n\n\n\/\/ Configure SSL client\nssl_client.setInsecure();\n#if defined(ESP32)\n ssl_client.setConnectionTimeout(1000);\n ssl_client.setHandshakeTimeout(5);\n#elif defined(ESP8266)\n ssl_client.setTimeout(1000); \/\/ Set connection timeout\n ssl_client.setBufferSizes(4096, 1024); \/\/ Set buffer sizes\n#endif<\/code><\/pre>\n\n\n\ninitializeApp(aClient, app, getAuth(user_auth), processData, \"\ud83d\udd10 authTask\");<\/code><\/pre>\n\n\n\nloop()<\/h4>\n\n\n\n
void loop(){\n app.loop();<\/code><\/pre>\n\n\n\nif (app.ready() && !taskComplete){\n taskComplete = true;<\/code><\/pre>\n\n\n\nFirebase.printf(\"User UID: %sn\", app.getUid().c_str());<\/code><\/pre>\n\n\n\n Firebase.printf(\"Auth Token: %sn\", app.getToken().c_str());\n Firebase.printf(\"Refresh Token: %sn\", app.getRefreshToken().c_str());\n print_token_type(app);<\/code><\/pre>\n\n\n\nDemonstration<\/h1>\n\n\n\n
monitor_speed = 115200<\/code><\/pre>\n\n\n\n![\"ESP32\/ESP8266](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2021\/11\/Authentication_Get_User_UID.png?resize=699%2C371&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\n![\"Firebase](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2021\/11\/user-logged-in-firebase-esp32.png?resize=665%2C236&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\n\n
Wrapping Up<\/h2>\n\n\n\n
\n
\n
\n