Add data to Cloud Firestore

This document explains how to set, add, or update individual documents in Cloud Firestore. To write data in bulk, see Transactions and batched writes.

Overview

You can write data to Cloud Firestore in one of the following ways:

  • Set the data of a document within a collection, explicitly specifying a document identifier.
  • Add a new document to a collection. In this case, Cloud Firestore automatically generates the document identifier.
  • Create an empty document with an automatically generated identifier, and assign data to it later.

Before you begin

Before you can initialize Cloud Firestore to set, add, or update data, you must complete the following steps:

Initialize Cloud Firestore

Initialize an instance of Cloud Firestore:

Web

import { initializeApp } from "firebase/app";
import { getFirestore } from "firebase/firestore";

// TODO: Replace the following with your app's Firebase project configuration
// See: https://support.google.com/firebase/answer/7015592
const firebaseConfig = {
    FIREBASE_CONFIGURATION
};

// Initialize Firebase
const app = initializeApp(firebaseConfig);


// Initialize Cloud Firestore and get a reference to the service
const db = getFirestore(app);

Replace FIREBASE_CONFIGURATION with your web app's firebaseConfig.

To persist data when the device loses its connection, see the Enable Offline Data documentation.

Web

import firebase from "firebase/app";
import "firebase/firestore";

// TODO: Replace the following with your app's Firebase project configuration
// See: https://support.google.com/firebase/answer/7015592
const firebaseConfig = {
    FIREBASE_CONFIGURATION
};

// Initialize Firebase
firebase.initializeApp(firebaseConfig);


// Initialize Cloud Firestore and get a reference to the service
const db = firebase.firestore();

Replace FIREBASE_CONFIGURATION with your web app's firebaseConfig.

To persist data when the device loses its connection, see the Enable Offline Data documentation.

Swift
Note: This product is not available on watchOS and App Clip targets.
import FirebaseCore
import FirebaseFirestore
FirebaseApp.configure()

let db = Firestore.firestore()
Objective-C
Note: This product is not available on watchOS and App Clip targets.
@import FirebaseCore;
@import FirebaseFirestore;

// Use Firebase library to configure APIs
[FIRApp configure];
  
FIRFirestore *defaultFirestore = [FIRFirestore firestore];

Kotlin+KTX

// Access a Cloud Firestore instance from your Activity
val db = Firebase.firestore

Java

// Access a Cloud Firestore instance from your Activity
FirebaseFirestore db = FirebaseFirestore.getInstance();

Dart

db = FirebaseFirestore.instance;
Java
The Cloud Firestore SDK is initialized in different ways depending on your environment. Below are the most common methods. For a complete reference, see Initialize the Admin SDK.
  • Initialize on Google Cloud
    import com.google.auth.oauth2.GoogleCredentials;
    import com.google.cloud.firestore.Firestore;
    
    import com.google.firebase.FirebaseApp;
    import com.google.firebase.FirebaseOptions;
    
    // Use the application default credentials
    GoogleCredentials credentials = GoogleCredentials.getApplicationDefault();
    FirebaseOptions options = new FirebaseOptions.Builder()
        .setCredentials(credentials)
        .setProjectId(projectId)
        .build();
    FirebaseApp.initializeApp(options);
    
    Firestore db = FirestoreClient.getFirestore();
  • Initialize on your own server

    To use the Firebase Admin SDK on your own server, use a service account.

    Go to IAM & admin > Service accounts in the Google Cloud console. Generate a new private key and save the JSON file. Then use the file to initialize the SDK:

    import com.google.auth.oauth2.GoogleCredentials;
    import com.google.cloud.firestore.Firestore;
    
    import com.google.firebase.FirebaseApp;
    import com.google.firebase.FirebaseOptions;
    
    // Use a service account
    InputStream serviceAccount = new FileInputStream("path/to/serviceAccount.json");
    GoogleCredentials credentials = GoogleCredentials.fromStream(serviceAccount);
    FirebaseOptions options = new FirebaseOptions.Builder()
        .setCredentials(credentials)
        .build();
    FirebaseApp.initializeApp(options);
    
    Firestore db = FirestoreClient.getFirestore();
  • Python
    The Cloud Firestore SDK is initialized in different ways depending on your environment. Below are the most common methods. For a complete reference, see Initialize the Admin SDK.
  • Initialize on Google Cloud
    import firebase_admin
    from firebase_admin import firestore
    
    # Application Default credentials are automatically created.
    app = firebase_admin.initialize_app()
    db = firestore.client()

    An existing application default credential can also be used to initialize the SDK.

    import firebase_admin
    from firebase_admin import credentials
    from firebase_admin import firestore
    
    # Use the application default credentials.
    cred = credentials.ApplicationDefault()
    
    firebase_admin.initialize_app(cred)
    db = firestore.client()
  • Initialize on your own server

    To use the Firebase Admin SDK on your own server, use a service account.

    Go to IAM & admin > Service accounts in the Google Cloud console. Generate a new private key and save the JSON file. Then use the file to initialize the SDK:

    import firebase_admin
    from firebase_admin import credentials
    from firebase_admin import firestore
    
    # Use a service account.
    cred = credentials.Certificate('path/to/serviceAccount.json')
    
    app = firebase_admin.initialize_app(cred)
    
    db = firestore.client()
  • Python

    The Cloud Firestore SDK is initialized in different ways depending on your environment. Below are the most common methods. For a complete reference, see Initialize the Admin SDK.
  • Initialize on Google Cloud
    import firebase_admin
    from firebase_admin import firestore_async
    
    # Application Default credentials are automatically created.
    app = firebase_admin.initialize_app()
    db = firestore_async.client()

    An existing application default credential can also be used to initialize the SDK.

    import firebase_admin
    from firebase_admin import credentials
    from firebase_admin import firestore_async
    
    # Use the application default credentials.
    cred = credentials.ApplicationDefault()
    
    firebase_admin.initialize_app(cred)
    db = firestore_async.client()
  • Initialize on your own server

    To use the Firebase Admin SDK on your own server, use a service account.

    Go to IAM & admin > Service accounts in the Google Cloud console. Generate a new private key and save the JSON file. Then use the file to initialize the SDK:

    import firebase_admin
    from firebase_admin import credentials
    from firebase_admin import firestore_async
    
    # Use a service account.
    cred = credentials.Certificate('path/to/serviceAccount.json')
    
    app = firebase_admin.initialize_app(cred)
    
    db = firestore_async.client()
  • C++
    // Make sure the call to `Create()` happens some time before you call Firestore::GetInstance().
    App::Create();
    Firestore* db = Firestore::GetInstance();
    Node.js
    The Cloud Firestore SDK is initialized in different ways depending on your environment. Below are the most common methods. For a complete reference, see Initialize the Admin SDK.
    • Initialize on Cloud Functions
      const { initializeApp, applicationDefault, cert } = require('firebase-admin/app');
      const { getFirestore, Timestamp, FieldValue, Filter } = require('firebase-admin/firestore');
      initializeApp();
      
      const db = getFirestore();
      
    • Initialize on Google Cloud
      const { initializeApp, applicationDefault, cert } = require('firebase-admin/app');
      const { getFirestore, Timestamp, FieldValue, Filter } = require('firebase-admin/firestore');
      initializeApp({
        credential: applicationDefault()
      });
      
      const db = getFirestore();
    • Initialize on your own server

      To use the Firebase Admin SDK on your own server (or any other Node.js environment), use a service account. Go to IAM & admin > Service accounts in the Google Cloud console. Generate a new private key and save the JSON file. Then use the file to initialize the SDK:

      const { initializeApp, applicationDefault, cert } = require('firebase-admin/app');
      const { getFirestore, Timestamp, FieldValue, Filter } = require('firebase-admin/firestore');
      const serviceAccount = require('./path/to/serviceAccountKey.json');
      
      initializeApp({
        credential: cert(serviceAccount)
      });
      
      const db = getFirestore();
      
    Go
    The Cloud Firestore SDK is initialized in different ways depending on your environment. Below are the most common methods. For a complete reference, see Initialize the Admin SDK.
  • Initialize on Google Cloud
    import (
      "log"
    
      firebase "firebase.google.com/go"
      "google.golang.org/api/option"
    )
    
    // Use the application default credentials
    ctx := context.Background()
    conf := &firebase.Config{ProjectID: projectID}
    app, err := firebase.NewApp(ctx, conf)
    if err != nil {
      log.Fatalln(err)
    }
    
    client, err := app.Firestore(ctx)
    if err != nil {
      log.Fatalln(err)
    }
    defer client.Close()
  • Initialize on your own server

    To use the Firebase Admin SDK on your own server, use a service account.

    Go to IAM & admin > Service accounts in the Google Cloud console. Generate a new private key and save the JSON file. Then use the file to initialize the SDK:

    import (
      "log"
    
      firebase "firebase.google.com/go"
      "google.golang.org/api/option"
    )
    
    // Use a service account
    ctx := context.Background()
    sa := option.WithCredentialsFile("path/to/serviceAccount.json")
    app, err := firebase.NewApp(ctx, nil, sa)
    if err != nil {
      log.Fatalln(err)
    }
    
    client, err := app.Firestore(ctx)
    if err != nil {
      log.Fatalln(err)
    }
    defer client.Close()
  • PHP

    PHP

    For more on installing and creating a Cloud Firestore client, refer to Cloud Firestore Client Libraries.

    use Google\Cloud\Firestore\FirestoreClient;
    
    /**
     * Initialize Cloud Firestore with default project ID.
     */
    function setup_client_create(string $projectId = null)
    {
        // Create the Cloud Firestore client
        if (empty($projectId)) {
            // The `projectId` parameter is optional and represents which project the
            // client will act on behalf of. If not supplied, the client falls back to
            // the default project inferred from the environment.
            $db = new FirestoreClient();
            printf('Created Cloud Firestore client with default project ID.' . PHP_EOL);
        } else {
            $db = new FirestoreClient([
                'projectId' => $projectId,
            ]);
            printf('Created Cloud Firestore client with project ID: %s' . PHP_EOL, $projectId);
        }
    }
    Unity
    using Firebase.Firestore;
    using Firebase.Extensions;
    FirebaseFirestore db = FirebaseFirestore.DefaultInstance;
    C#

    C#

    For more on installing and creating a Cloud Firestore client, refer to Cloud Firestore Client Libraries.

    FirestoreDb db = FirestoreDb.Create(project);
    Console.WriteLine("Created Cloud Firestore client with project ID: {0}", project);
    Ruby
    require "google/cloud/firestore"
    
    # The `project_id` parameter is optional and represents which project the
    # client will act on behalf of. If not supplied, the client falls back to the
    # default project inferred from the environment.
    firestore = Google::Cloud::Firestore.new project_id: project_id
    
    puts "Created Cloud Firestore client with given project ID."

    Set a document

    To create or overwrite a single document, use the following language-specific set() methods:

    Web

    Use the setDoc() method:

    import { doc, setDoc } from "firebase/firestore"; 
    
    // Add a new document in collection "cities"
    await setDoc(doc(db, "cities", "LA"), {
      name: "Los Angeles",
      state: "CA",
      country: "USA"
    });

    Web

    Use the set() method:

    // Add a new document in collection "cities"
    db.collection("cities").doc("LA").set({
        name: "Los Angeles",
        state: "CA",
        country: "USA"
    })
    .then(() => {
        console.log("Document successfully written!");
    })
    .catch((error) => {
        console.error("Error writing document: ", error);
    });
    Swift

    Use the setData() method:

    Note: This product is not available on watchOS and App Clip targets.
    // Add a new document in collection "cities"
    do {
      try await db.collection("cities").document("LA").setData([
        "name": "Los Angeles",
        "state": "CA",
        "country": "USA"
      ])
      print("Document successfully written!")
    } catch {
      print("Error writing document: \(error)")
    }
    Objective-C

    Use the setData: method:

    Note: This product is not available on watchOS and App Clip targets.
    // Add a new document in collection "cities"
    [[[self.db collectionWithPath:@"cities"] documentWithPath:@"LA"] setData:@{
      @"name": @"Los Angeles",
      @"state": @"CA",
      @"country": @"USA"
    } completion:^(NSError * _Nullable error) {
      if (error != nil) {
        NSLog(@"Error writing document: %@", error);
      } else {
        NSLog(@"Document successfully written!");
      }
    }];

    Kotlin+KTX

    Use the set() method:

    val city = hashMapOf(
        "name" to "Los Angeles",
        "state" to "CA",
        "country" to "USA",
    )
    
    db.collection("cities").document("LA")
        .set(city)
        .addOnSuccessListener { Log.d(TAG, "DocumentSnapshot successfully written!") }
        .addOnFailureListener { e -> Log.w(TAG, "Error writing document", e) }

    Java

    Use the set() method:

    Map<String, Object> city = new HashMap<>();
    city.put("name", "Los Angeles");
    city.put("state", "CA");
    city.put("country", "USA");
    
    db.collection("cities").document("LA")
            .set(city)
            .addOnSuccessListener(new OnSuccessListener<Void>() {
                @Override
                public void onSuccess(Void aVoid) {
                    Log.d(TAG, "DocumentSnapshot successfully written!");
                }
            })
            .addOnFailureListener(new OnFailureListener() {
                @Override
                public void onFailure(@NonNull Exception e) {
                    Log.w(TAG, "Error writing document", e);
                }
            });

    Dart

    Use the set() method:

    final city = <String, String>{
      "name": "Los Angeles",
      "state": "CA",
      "country": "USA"
    };
    
    db
        .collection("cities")
        .doc("LA")
        .set(city)
        .onError((e, _) => print("Error writing document: $e"));
    Java

    Use the set() method:

    // Create a Map to store the data we want to set
    Map<String, Object> docData = new HashMap<>();
    docData.put("name", "Los Angeles");
    docData.put("state", "CA");
    docData.put("country", "USA");
    docData.put("regions", Arrays.asList("west_coast", "socal"));
    // Add a new document (asynchronously) in collection "cities" with id "LA"
    ApiFuture<WriteResult> future = db.collection("cities").document("LA").set(docData);
    // ...
    // future.get() blocks on response
    System.out.println("Update time : " + future.get().getUpdateTime());
    Python

    Use the set() method:

    data = {"name": "Los Angeles", "state": "CA", "country": "USA"}
    
    # Add a new doc in collection 'cities' with ID 'LA'
    db.collection("cities").document("LA").set(data)

    Python

    Use the set() method:

    data = {"name": "Los Angeles", "state": "CA", "country": "USA"}
    
    # Add a new doc in collection 'cities' with ID 'LA'
    await db.collection("cities").document("LA").set(data)
    C++

    Use the Set() method:

    // Add a new document in collection 'cities'
    db->Collection("cities")
        .Document("LA")
        .Set({{"name", FieldValue::String("Los Angeles")},
              {"state", FieldValue::String("CA")},
              {"country", FieldValue::String("USA")}})
        .OnCompletion([](const Future<void>& future) {
          if (future.error() == Error::kErrorOk) {
            std::cout << "DocumentSnapshot successfully written!" << std::endl;
          } else {
            std::cout << "Error writing document: " << future.error_message()
                      << std::endl;
          }
        });
    Node.js

    Use the set() method:

    const data = {
      name: 'Los Angeles',
      state: 'CA',
      country: 'USA'
    };
    
    // Add a new document in collection "cities" with ID 'LA'
    const res = await db.collection('cities').doc('LA').set(data);
    Go

    Use the Set() method:

    
    import (
    	"context"
    	"log"
    
    	"cloud.google.com/go/firestore"
    )
    
    func addDocAsMap(ctx context.Context, client *firestore.Client) error {
    	_, err := client.Collection("cities").Doc("LA").Set(ctx, map[string]interface{}{
    		"name":    "Los Angeles",
    		"state":   "CA",
    		"country": "USA",
    	})
    	if err != nil {
    		// Handle any errors in an appropriate way, such as returning them.
    		log.Printf("An error has occurred: %s", err)
    	}
    
    	return err
    }
    
    PHP

    Use the set() method:

    PHP

    For more on installing and creating a Cloud Firestore client, refer to Cloud Firestore Client Libraries.

    $data = [
        'name' => 'Los Angeles',
        'state' => 'CA',
        'country' => 'USA'
    ];
    $db->collection('samples/php/cities')->document('LA')->set($data);
    Unity

    Use the SetAsync() method:

    DocumentReference docRef = db.Collection("cities").Document("LA");
    Dictionary<string, object> city = new Dictionary<string, object>
    {
    	{ "Name", "Los Angeles" },
    	{ "State", "CA" },
    	{ "Country", "USA" }
    };
    docRef.SetAsync(city).ContinueWithOnMainThread(task => {
    	Debug.Log("Added data to the LA document in the cities collection.");
    });
    C#

    Use the SetAsync() method:

    DocumentReference docRef = db.Collection("cities").Document("LA");
    Dictionary<string, object> city = new Dictionary<string, object>
    {
        { "name", "Los Angeles" },
        { "state", "CA" },
        { "country", "USA" }
    };
    await docRef.SetAsync(city);
    Ruby

    Use the set() method:

    city_ref = firestore.doc "#{collection_path}/LA"
    
    data = {
      name:    "Los Angeles",
      state:   "CA",
      country: "USA"
    }
    
    city_ref.set data

    If the document does not exist, it will be created. If the document does exist, its contents will be overwritten with the newly provided data, unless you specify that the data should be merged into the existing document, as follows:

    Web

    import { doc, setDoc } from "firebase/firestore"; 
    
    const cityRef = doc(db, 'cities', 'BJ');
    setDoc(cityRef, { capital: true }, { merge: true });

    Web

    var cityRef = db.collection('cities').doc('BJ');
    
    var setWithMerge = cityRef.set({
        capital: true
    }, { merge: true });
    Swift
    Note: This product is not available on watchOS and App Clip targets.
    // Update one field, creating the document if it does not exist.
    db.collection("cities").document("BJ").setData([ "capital": true ], merge: true)
    Objective-C
    Note: This product is not available on watchOS and App Clip targets.
    // Write to the document reference, merging data with existing
    // if the document already exists
    [[[self.db collectionWithPath:@"cities"] documentWithPath:@"BJ"]
         setData:@{ @"capital": @YES }
         merge:YES
         completion:^(NSError * _Nullable error) {
           // ...
         }];

    Kotlin+KTX

    // Update one field, creating the document if it does not already exist.
    val data = hashMapOf("capital" to true)
    
    db.collection("cities").document("BJ")
        .set(data, SetOptions.merge())

    Java

    // Update one field, creating the document if it does not already exist.
    Map<String, Object> data = new HashMap<>();
    data.put("capital", true);
    
    db.collection("cities").document("BJ")
            .set(data, SetOptions.merge());

    Dart

    // Update one field, creating the document if it does not already exist.
    final data = {"capital": true};
    
    db.collection("cities").doc("BJ").set(data, SetOptions(merge: true));
    Java
    // asynchronously update doc, create the document if missing
    Map<String, Object> update = new HashMap<>();
    update.put("capital", true);
    
    ApiFuture<WriteResult> writeResult =
        db.collection("cities").document("BJ").set(update, SetOptions.merge());
    // ...
    System.out.println("Update time : " + writeResult.get().getUpdateTime());
    Python
    city_ref = db.collection("cities").document("BJ")
    
    city_ref.set({"capital": True}, merge=True)

    Python

    city_ref = db.collection("cities").document("BJ")
    
    await city_ref.set({"capital": True}, merge=True)
    C++
    db->Collection("cities").Document("BJ").Set(
        {{"capital", FieldValue::Boolean(true)}}, SetOptions::Merge());
    Node.js
    const cityRef = db.collection('cities').doc('BJ');
    
    const res = await cityRef.set({
      capital: true
    }, { merge: true });
    Go
    
    import (
    	"context"
    	"log"
    
    	"cloud.google.com/go/firestore"
    )
    
    func updateDocCreateIfMissing(ctx context.Context, client *firestore.Client) error {
    	_, err := client.Collection("cities").Doc("BJ").Set(ctx, map[string]interface{}{
    		"capital": true,
    	}, firestore.MergeAll)
    
    	if err != nil {
    		// Handle any errors in an appropriate way, such as returning them.
    		log.Printf("An error has occurred: %s", err)
    	}
    
    	return err
    }
    
    PHP

    PHP

    For more on installing and creating a Cloud Firestore client, refer to Cloud Firestore Client Libraries.

    $cityRef = $db->collection('samples/php/cities')->document('BJ');
    $cityRef->set([
        'capital' => true
    ], ['merge' => true]);
    Unity
    DocumentReference docRef = db.Collection("cities").Document("LA");
    Dictionary<string, object> update = new Dictionary<string, object>
    {
    	{ "capital", false }
    };
    docRef.SetAsync(update, SetOptions.MergeAll);
    C#
    DocumentReference docRef = db.Collection("cities").Document("LA");
    Dictionary<string, object> update = new Dictionary<string, object>
    {
        { "capital", false }
    };
    await docRef.SetAsync(update, SetOptions.MergeAll);
    Ruby
    city_ref = firestore.doc "#{collection_path}/LA"
    city_ref.set({ capital: false }, merge: true)

    If you're not sure whether the document exists, pass the option to merge the new data with any existing document to avoid overwriting entire documents. For documents that contain maps, if you specify a set with a field that contains an empty map, the map field of the target document is overwritten.

    Data types

    Cloud Firestore lets you write a variety of data types inside a document, including strings, booleans, numbers, dates, null, and nested arrays and objects. Cloud Firestore always stores numbers as doubles, regardless of what type of number you use in your code.

    Web

    import { doc, setDoc, Timestamp } from "firebase/firestore"; 
    
    const docData = {
        stringExample: "Hello world!",
        booleanExample: true,
        numberExample: 3.14159265,
        dateExample: Timestamp.fromDate(new Date("December 10, 1815")),
        arrayExample: [5, true, "hello"],
        nullExample: null,
        objectExample: {
            a: 5,
            b: {
                nested: "foo"
            }
        }
    };
    await setDoc(doc(db, "data", "one"), docData);

    Web

    var docData = {
        stringExample: "Hello world!",
        booleanExample: true,
        numberExample: 3.14159265,
        dateExample: firebase.firestore.Timestamp.fromDate(new Date("December 10, 1815")),
        arrayExample: [5, true, "hello"],
        nullExample: null,
        objectExample: {
            a: 5,
            b: {
                nested: "foo"
            }
        }
    };
    db.collection("data").doc("one").set(docData).then(() => {
        console.log("Document successfully written!");
    });
    Swift
    Note: This product is not available on watchOS and App Clip targets.
    let docData: [String: Any] = [
      "stringExample": "Hello world!",
      "booleanExample": true,
      "numberExample": 3.14159265,
      "dateExample": Timestamp(date: Date()),
      "arrayExample": [5, true, "hello"],
      "nullExample": NSNull(),
      "objectExample": [
        "a": 5,
        "b": [
          "nested": "foo"
        ]
      ]
    ]
    do {
      try await db.collection("data").document("one").setData(docData)
      print("Document successfully written!")
    } catch {
      print("Error writing document: \(error)")
    }
    Objective-C
    Note: This product is not available on watchOS and App Clip targets.
    NSDictionary *docData = @{
      @"stringExample": @"Hello world!",
      @"booleanExample": @YES,
      @"numberExample": @3.14,
      @"dateExample": [FIRTimestamp timestampWithDate:[NSDate date]],
      @"arrayExample": @[@5, @YES, @"hello"],
      @"nullExample": [NSNull null],
      @"objectExample": @{
        @"a": @5,
        @"b": @{
          @"nested": @"foo"
        }
      }
    };
    
    [[[self.db collectionWithPath:@"data"] documentWithPath:@"one"] setData:docData
        completion:^(NSError * _Nullable error) {
          if (error != nil) {
            NSLog(@"Error writing document: %@", error);
          } else {
            NSLog(@"Document successfully written!");
          }
        }];

    Kotlin+KTX

    val docData = hashMapOf(
        "stringExample" to "Hello world!",
        "booleanExample" to true,
        "numberExample" to 3.14159265,
        "dateExample" to Timestamp(Date()),
        "listExample" to arrayListOf(1, 2, 3),
        "nullExample" to null,
    )
    
    val nestedData = hashMapOf(
        "a" to 5,
        "b" to true,
    )
    
    docData["objectExample"] = nestedData
    
    db.collection("data").document("one")
        .set(docData)
        .addOnSuccessListener { Log.d(TAG, "DocumentSnapshot successfully written!") }
        .addOnFailureListener { e -> Log.w(TAG, "Error writing document", e) }

    Java

    Map<String, Object> docData = new HashMap<>();
    docData.put("stringExample", "Hello world!");
    docData.put("booleanExample", true);
    docData.put("numberExample", 3.14159265);
    docData.put("dateExample", new Timestamp(new Date()));
    docData.put("listExample", Arrays.asList(1, 2, 3));
    docData.put("nullExample", null);
    
    Map<String, Object> nestedData = new HashMap<>();
    nestedData.put("a", 5);
    nestedData.put("b", true);
    
    docData.put("objectExample", nestedData);
    
    db.collection("data").document("one")
            .set(docData)
            .addOnSuccessListener(new OnSuccessListener<Void>() {
                @Override
                public void onSuccess(Void aVoid) {
                    Log.d(TAG, "DocumentSnapshot successfully written!");
                }
            })
            .addOnFailureListener(new OnFailureListener() {
                @Override
                public void onFailure(@NonNull Exception e) {
                    Log.w(TAG, "Error writing document", e);
                }
            });

    Dart

    final docData = {
      "stringExample": "Hello world!",
      "booleanExample": true,
      "numberExample": 3.14159265,
      "dateExample": Timestamp.now(),
      "listExample": [1, 2, 3],
      "nullExample": null
    };
    
    final nestedData = {
      "a": 5,
      "b": true,
    };
    
    docData["objectExample"] = nestedData;
    
    db
        .collection("data")
        .doc("one")
        .set(docData)
        .onError((e, _) => print("Error writing document: $e"));
    Java
    Map<String, Object> docData = new HashMap<>();
    docData.put("stringExample", "Hello, World");
    docData.put("booleanExample", false);
    docData.put("numberExample", 3.14159265);
    docData.put("nullExample", null);
    
    ArrayList<Object> arrayExample = new ArrayList<>();
    Collections.addAll(arrayExample, 5L, true, "hello");
    docData.put("arrayExample", arrayExample);
    
    Map<String, Object> objectExample = new HashMap<>();
    objectExample.put("a", 5L);
    objectExample.put("b", true);
    
    docData.put("objectExample", objectExample);
    
    ApiFuture<WriteResult> future = db.collection("data").document("one").set(docData);
    System.out.println("Update time : " + future.get().getUpdateTime());
    Python
    data = {
        "stringExample": "Hello, World!",
        "booleanExample": True,
        "numberExample": 3.14159265,
        "dateExample": datetime.datetime.now(tz=datetime.timezone.utc),
        "arrayExample": [5, True, "hello"],
        "nullExample": None,
        "objectExample": {"a": 5, "b": True},
    }
    
    db.collection("data").document("one").set(data)

    Python

    data = {
        "stringExample": "Hello, World!",
        "booleanExample": True,
        "numberExample": 3.14159265,
        "dateExample": datetime.datetime.now(tz=datetime.timezone.utc),
        "arrayExample": [5, True, "hello"],
        "nullExample": None,
        "objectExample": {"a": 5, "b": True},
    }
    
    await db.collection("data").document("one").set(data)
    C++
    MapFieldValue doc_data{
        {"stringExample", FieldValue::String("Hello world!")},
        {"booleanExample", FieldValue::Boolean(true)},
        {"numberExample", FieldValue::Double(3.14159265)},
        {"dateExample", FieldValue::Timestamp(Timestamp::Now())},
        {"arrayExample", FieldValue::Array({FieldValue::Integer(1),
                                            FieldValue::Integer(2),
                                            FieldValue::Integer(3)})},
        {"nullExample", FieldValue::Null()},
        {"objectExample",
         FieldValue::Map(
             {{"a", FieldValue::Integer(5)},
              {"b", FieldValue::Map(
                        {{"nested", FieldValue::String("foo")}})}})},
    };
    
    db->Collection("data").Document("one").Set(doc_data).OnCompletion(
        [](const Future<void>& future) {
          if (future.error() == Error::kErrorOk) {
            std::cout << "DocumentSnapshot successfully written!" << std::endl;
          } else {
            std::cout << "Error writing document: " << future.error_message()
                      << std::endl;
          }
        });
    Node.js
    const data = {
      stringExample: 'Hello, World!',
      booleanExample: true,
      numberExample: 3.14159265,
      dateExample: Timestamp.fromDate(new Date('December 10, 1815')),
      arrayExample: [5, true, 'hello'],
      nullExample: null,
      objectExample: {
        a: 5,
        b: true
      }
    };
    
    const res = await db.collection('data').doc('one').set(data);
    Go
    
    import (
    	"context"
    	"log"
    	"time"
    
    	"cloud.google.com/go/firestore"
    )
    
    func addDocDataTypes(ctx context.Context, client *firestore.Client) error {
    	doc := make(map[string]interface{})
    	doc["stringExample"] = "Hello world!"
    	doc["booleanExample"] = true
    	doc["numberExample"] = 3.14159265
    	doc["dateExample"] = time.Now()
    	doc["arrayExample"] = []interface{}{5, true, "hello"}
    	doc["nullExample"] = nil
    	doc["objectExample"] = map[string]interface{}{
    		"a": 5,
    		"b": true,
    	}
    
    	_, err := client.Collection("data").Doc("one").Set(ctx, doc)
    	if err != nil {
    		// Handle any errors in an appropriate way, such as returning them.
    		log.Printf("An error has occurred: %s", err)
    	}
    
    	return err
    }
    
    PHP

    PHP

    For more on installing and creating a Cloud Firestore client, refer to Cloud Firestore Client Libraries.

    $data = [
        'stringExample' => 'Hello World',
        'booleanExample' => true,
        'numberExample' => 3.14159265,
        'dateExample' => new Timestamp(new DateTime()),
        'arrayExample' => array(5, true, 'hello'),
        'nullExample' => null,
        'objectExample' => ['a' => 5, 'b' => true],
        'documentReferenceExample' => $db->collection('samples/php/data')->document('two'),
    ];
    $db->collection('samples/php/data')->document('one')->set($data);
    printf('Set multiple data-type data for the one document in the data collection.' . PHP_EOL);
    Unity
    DocumentReference docRef = db.Collection("data").Document("one");
    Dictionary<string, object> docData = new Dictionary<string, object>
    {
    	{ "stringExample", "Hello World" },
    	{ "booleanExample", false },
    	{ "numberExample", 3.14159265 },
    	{ "nullExample", null },
    	{ "arrayExample", new List<object>() { 5, true, "Hello" } },
    	{ "objectExample", new Dictionary<string, object>
    		{
    			{ "a", 5 },
    			{ "b", true },
    		}
    	},
    };
    
    docRef.SetAsync(docData);
    C#
    DocumentReference docRef = db.Collection("data").Document("one");
    Dictionary<string, object> docData = new Dictionary<string, object>
    {
        { "stringExample", "Hello World" },
        { "booleanExample", false },
        { "numberExample", 3.14159265 },
        { "nullExample", null },
        { "arrayExample", new object[] { 5, true, "Hello" } },
        { "objectExample", new Dictionary<string, object>
            {
                { "a", 5 },
                { "b", true},
            }
        }
    };
    
    await docRef.SetAsync(docData);
    Ruby
    doc_ref = firestore.doc "#{collection_path}/one"
    
    data = {
      stringExample:  "Hello, World!",
      booleanExample: true,
      numberExample:  3.14159265,
      dateExample:    DateTime.now,
      arrayExample:   [5, true, "hello"],
      nullExample:    nil,
      objectExample:  {
        a: 5,
        b: true
      }
    }
    
    doc_ref.set data

    Custom objects

    Using Map or Dictionary objects to represent your documents is often inconvenient, so Cloud Firestore supports writing documents with custom classes. Cloud Firestore converts the objects to supported data types.

    Using custom classes, you can rewrite the initial example in the following way:

    Web

    class City {
        constructor (name, state, country ) {
            this.name = name;
            this.state = state;
            this.country = country;
        }
        toString() {
            return this.name + ', ' + this.state + ', ' + this.country;
        }
    }
    
    // Firestore data converter
    const cityConverter = {
        toFirestore: (city) => {
            return {
                name: city.name,
                state: city.state,
                country: city.country
                };
        },
        fromFirestore: (snapshot, options) => {
            const data = snapshot.data(options);
            return new City(data.name, data.state, data.country);
        }
    };

    Web

    class City {
        constructor (name, state, country ) {
            this.name = name;
            this.state = state;
            this.country = country;
        }
        toString() {
            return this.name + ', ' + this.state + ', ' + this.country;
        }
    }
    
    // Firestore data converter
    var cityConverter = {
        toFirestore: function(city) {
            return {
                name: city.name,
                state: city.state,
                country: city.country
                };
        },
        fromFirestore: function(snapshot, options){
            const data = snapshot.data(options);
            return new City(data.name, data.state, data.country);
        }
    };
    Swift
    Note: This product is not available on watchOS and App Clip targets.
    public struct City: Codable {
    
      let name: String
      let state: String?
      let country: String?
      let isCapital: Bool?
      let population: Int64?
    
      enum CodingKeys: String, CodingKey {
        case name
        case state
        case country
        case isCapital = "capital"
        case population
      }
    
    }
    Objective-C
    Note: This product is not available on watchOS and App Clip targets.
    // This isn't supported in Objective-C.
      

    Kotlin+KTX

    data class City(
        val name: String? = null,
        val state: String? = null,
        val country: String? = null,
        @field:JvmField // use this annotation if your Boolean field is prefixed with 'is'
        val isCapital: Boolean? = null,
        val population: Long? = null,
        val regions: List<String>? = null,
    )

    Java

    Each custom class must have a public constructor that takes no arguments. In addition, the class must include a public getter for each property.

    public class City {
    
    
        private String name;
        private String state;
        private String country;
        private boolean capital;
        private long population;
        private List<String> regions;
    
        public City() {}
    
        public City(String name, String state, String country, boolean capital, long population, List<String> regions) {
            // ...
        }
    
        public String getName() {
            return name;
        }
    
        public String getState() {
            return state;
        }
    
        public String getCountry() {
            return country;
        }
    
        public boolean isCapital() {
            return capital;
        }
    
        public long getPopulation() {
            return population;
        }
    
        public List<String> getRegions() {
            return regions;
        }
    
    }

    Dart

    class City {
      final String? name;
      final String? state;
      final String? country;
      final bool? capital;
      final int? population;
      final List<String>? regions;
    
      City({
        this.name,
        this.state,
        this.country,
        this.capital,
        this.population,
        this.regions,
      });
    
      factory City.fromFirestore(
        DocumentSnapshot<Map<String, dynamic>> snapshot,
        SnapshotOptions? options,
      ) {
        final data = snapshot.data();
        return City(
          name: data?['name'],
          state: data?['state'],
          country: data?['country'],
          capital: data?['capital'],
          population: data?['population'],
          regions:
              data?['regions'] is Iterable ? List.from(data?['regions']) : null,
        );
      }
    
      Map<String, dynamic> toFirestore() {
        return {
          if (name != null) "name": name,
          if (state != null) "state": state,
          if (country != null) "country": country,
          if (capital != null) "capital": capital,
          if (population != null) "population": population,
          if (regions != null) "regions": regions,
        };
      }
    }
    Java
    public City() {
      // Must have a public no-argument constructor
    }
    
    // Initialize all fields of a city
    public City(
        String name,
        String state,
        String country,
        Boolean capital,
        Long population,
        List<String> regions) {
      this.name = name;
      this.state = state;
      this.country = country;
      this.capital = capital;
      this.population = population;
      this.regions = regions;
    }
    Python
    class City:
        def __init__(self, name, state, country, capital=False, population=0, regions=[]):
            self.name = name
            self.state = state
            self.country = country
            self.capital = capital
            self.population = population
            self.regions = regions
    
        @staticmethod
        def from_dict(source):
            # ...
    
        def to_dict(self):
            # ...
    
        def __repr__(self):
            return f"City(\
                    name={self.name}, \
                    country={self.country}, \
                    population={self.population}, \
                    capital={self.capital}, \
                    regions={self.regions}\
                )"
    
    

    Python

    class City:
        def __init__(self, name, state, country, capital=False, population=0, regions=[]):
            self.name = name
            self.state = state
            self.country = country
            self.capital = capital
            self.population = population
            self.regions = regions
    
        @staticmethod
        def from_dict(source):
            # ...
    
        def to_dict(self):
            # ...
    
        def __repr__(self):
            return f"City(\
                    name={self.name}, \
                    country={self.country}, \
                    population={self.population}, \
                    capital={self.capital}, \
                    regions={self.regions}\
                )"
    
    
    C++
    // This is not yet supported.
    Node.js
    // Node.js uses JavaScript objects
    Go
    
    // City represents a city.
    type City struct {
    	Name       string   `firestore:"name,omitempty"`
    	State      string   `firestore:"state,omitempty"`
    	Country    string   `firestore:"country,omitempty"`
    	Capital    bool     `firestore:"capital,omitempty"`
    	Population int64    `firestore:"population,omitempty"`
    	Density    int64    `firestore:"density,omitempty"`
    	Regions    []string `firestore:"regions,omitempty"`
    }
    
    PHP

    PHP

    For more on installing and creating a Cloud Firestore client, refer to Cloud Firestore Client Libraries.

    class City
    {
        /** @var string */
        public $name;
        /** @var string */
        public $state;
        /** @var string */
        public $country;
        /** @var bool */
        public $capital;
        /** @var int */
        public $population;
        /** @var array<string> */
        public $regions;
    
        /**
         * @param array<string> $regions
         */
        public function __construct(
            string $name,
            string $state,
            string $country,
            bool $capital = false,
            int $population = 0,
            array $regions = []
        ) {
            $this->name = $name;
            $this->state = $state;
            $this->country = $country;
            $this->capital = $capital;
            $this->population = $population;
            $this->regions = $regions;
        }
    
        /**
         * @param array<mixed> $source
         */
        public static function fromArray(array $source): City
        {
            // implementation of fromArray is excluded for brevity
            # ...
        }
    
        /**
         * @return array<mixed>
         */
        public function toArray(): array
        {
            // implementation of toArray is excluded for brevity
            # ...
        }
    
        public function __toString()
        {
            // implementation of __toString is excluded for brevity
            # ...
        }
    }
    
    Unity
    [FirestoreData]
    public class City
    {
    	[FirestoreProperty]
    	public string Name { get; set; }
    
    	[FirestoreProperty]
    	public string State { get; set; }
    
    	[FirestoreProperty]
    	public string Country { get; set; }
    
    	[FirestoreProperty]
    	public bool Capital { get; set; }
    
    	[FirestoreProperty]
    	public long Population { get; set; }
    }
    C#
    [FirestoreData]
    public class City
    {
        [FirestoreProperty]
        public string Name { get; set; }
    
        [FirestoreProperty]
        public string State { get; set; }
    
        [FirestoreProperty]
        public string Country { get; set; }
    
        [FirestoreProperty]
        public bool Capital { get; set; }
    
        [FirestoreProperty]
        public long Population { get; set; }
    }
    Ruby
    // This isn't supported in Ruby

    Web

    import { doc, setDoc } from "firebase/firestore"; 
    
    // Set with cityConverter
    const ref = doc(db, "cities", "LA").withConverter(cityConverter);
    await setDoc(ref, new City("Los Angeles", "CA", "USA"));

    Web

    // Set with cityConverter
    db.collection("cities").doc("LA")
      .withConverter(cityConverter)
      .set(new City("Los Angeles", "CA", "USA"));
    Swift
    Note: This product is not available on watchOS and App Clip targets.
    let city = City(name: "Los Angeles",
                    state: "CA",
                    country: "USA",
                    isCapital: false,
                    population: 5000000)
    
    do {
      try db.collection("cities").document("LA").setData(from: city)
    } catch let error {
      print("Error writing city to Firestore: \(error)")
    }
    Objective-C
    Note: This product is not available on watchOS and App Clip targets.
    // This isn't supported in Objective-C.
      

    Kotlin+KTX

    val city = City(
        "Los Angeles",
        "CA",
        "USA",
        false,
        5000000L,
        listOf("west_coast", "socal"),
    )
    db.collection("cities").document("LA").set(city)

    Java

    City city = new City("Los Angeles", "CA", "USA",
            false, 5000000L, Arrays.asList("west_coast", "sorcal"));
    db.collection("cities").document("LA").set(city);

    Dart

    final city = City(
      name: "Los Angeles",
      state: "CA",
      country: "USA",
      capital: false,
      population: 5000000,
      regions: ["west_coast", "socal"],
    );
    final docRef = db
        .collection("cities")
        .withConverter(
          fromFirestore: City.fromFirestore,
          toFirestore: (City city, options) => city.toFirestore(),
        )
        .doc("LA");
    await docRef.set(city);
    Java
    City city =
        new City("Los Angeles", "CA", "USA", false, 3900000L, Arrays.asList("west_coast", "socal"));
    ApiFuture<WriteResult> future = db.collection("cities").document("LA").set(city);
    // block on response if required
    System.out.println("Update time : " + future.get().getUpdateTime());
    Python
    city = City(name="Los Angeles", state="CA", country="USA")
    db.collection("cities").document("LA").set(city.to_dict())

    Python

    city = City(name="Los Angeles", state="CA", country="USA")
    await db.collection("cities").document("LA").set(city.to_dict())
    C++
    // This is not yet supported.
    Node.js
    // Node.js uses JavaScript objects
    Go
    
    import (
    	"context"
    	"log"
    
    	"cloud.google.com/go/firestore"
    )
    
    func addDocAsEntity(ctx context.Context, client *firestore.Client) error {
    	city := City{
    		Name:    "Los Angeles",
    		Country: "USA",
    	}
    	_, err := client.Collection("cities").Doc("LA").Set(ctx, city)
    	if err != nil {
    		// Handle any errors in an appropriate way, such as returning them.
    		log.Printf("An error has occurred: %s", err)
    	}
    
    	return err
    }
    
    PHP
    // This isn't supported in PHP.
    Unity
    DocumentReference docRef = db.Collection("cities").Document("LA");
    City city = new City
    {
    	Name = "Los Angeles",
    	State = "CA",
    	Country = "USA",
    	Capital = false,
    	Population = 3900000L
    };
    docRef.SetAsync(city);
    C#
    DocumentReference docRef = db.Collection("cities").Document("LA");
    City city = new City
    {
        Name = "Los Angeles",
        State = "CA",
        Country = "USA",
        Capital = false,
        Population = 3900000L
    };
    await docRef.SetAsync(city);
    Ruby
    // This isn't supported in Ruby.

    Add a document

    When you use set() to create a document, you must specify an ID for the document to create, as shown in the following example:

    Web

    import { doc, setDoc } from "firebase/firestore"; 
    
    await setDoc(doc(db, "cities", "new-city-id"), data);

    Web

    db.collection("cities").doc("new-city-id").set(data);
    Swift
    Note: This product is not available on watchOS and App Clip targets.
    db.collection("cities").document("new-city-id").setData(data)
    Objective-C
    Note: This product is not available on watchOS and App Clip targets.
    [[[self.db collectionWithPath:@"cities"] documentWithPath:@"new-city-id"]
        setData:data];

    Kotlin+KTX

    db.collection("cities").document("new-city-id").set(data)

    Java

    db.collection("cities").document("new-city-id").set(data);

    Dart

    db.collection("cities").doc("new-city-id").set({"name": "Chicago"});
    Java
    db.collection("cities").document("new-city-id").set(data);
    Python
    db.collection("cities").document("new-city-id").set(data)

    Python

    await db.collection("cities").document("new-city-id").set(data)
    C++
    db->Collection("cities").Document("SF").Set({/*some data*/});
    Node.js
    await db.collection('cities').doc('new-city-id').set(data);
    Go
    
    import (
    	"context"
    	"log"
    
    	"cloud.google.com/go/firestore"
    )
    
    func addDocWithID(ctx context.Context, client *firestore.Client) error {
    	var data = make(map[string]interface{})
    
    	_, err := client.Collection("cities").Doc("new-city-id").Set(ctx, data)
    	if err != nil {
    		// Handle any errors in an appropriate way, such as returning them.
    		log.Printf("An error has occurred: %s", err)
    	}
    
    	return err
    }
    
    PHP

    PHP

    For more on installing and creating a Cloud Firestore client, refer to Cloud Firestore Client Libraries.

    $db->collection('samples/php/cities')->document('new-city-id')->set($data);
    Unity
    db.Collection("cities").Document("new-city-id").SetAsync(city);
    C#
    await db.Collection("cities").Document("new-city-id").SetAsync(city);
    Ruby
    city_ref = firestore.doc "#{collection_path}/new-city-id"
    city_ref.set data

    If there isn't a meaningful ID for the document, Cloud Firestore can auto-generate an ID for you. You can call the following language-specific add() methods:

    Web

    Use the addDoc() method:

    import { collection, addDoc } from "firebase/firestore"; 
    
    // Add a new document with a generated id.
    const docRef = await addDoc(collection(db, "cities"), {
      name: "Tokyo",
      country: "Japan"
    });
    console.log("Document written with ID: ", docRef.id);

    Web

    Use the add() method:

    // Add a new document with a generated id.
    db.collection("cities").add({
        name: "Tokyo",
        country: "Japan"
    })
    .then((docRef) => {
        console.log("Document written with ID: ", docRef.id);
    })
    .catch((error) => {
        console.error("Error adding document: ", error);
    });
    Swift

    Use the addDocument() method:

    Note: This product is not available on watchOS and App Clip targets.
    // Add a new document with a generated id.
    do {
      let ref = try await db.collection("cities").addDocument(data: [
        "name": "Tokyo",
        "country": "Japan"
      ])
      print("Document added with ID: \(ref.documentID)")
    } catch {
      print("Error adding document: \(error)")
    }
    Objective-C

    Use the addDocumentWithData: method:

    Note: This product is not available on watchOS and App Clip targets.
    // Add a new document with a generated id.
    __block FIRDocumentReference *ref =
        [[self.db collectionWithPath:@"cities"] addDocumentWithData:@{
          @"name": @"Tokyo",
          @"country": @"Japan"
        } completion:^(NSError * _Nullable error) {
          if (error != nil) {
            NSLog(@"Error adding document: %@", error);
          } else {
            NSLog(@"Document added with ID: %@", ref.documentID);
          }
        }];

    Kotlin+KTX

    Use the add() method:

    // Add a new document with a generated id.
    val data = hashMapOf(
        "name" to "Tokyo",
        "country" to "Japan",
    )
    
    db.collection("cities")
        .add(data)
        .addOnSuccessListener { documentReference ->