How Do I Save An Audio File Into Firebase Realtime Database?

I finished setting up my app's functionality to save text-based messages to RTDB (see code below). I now need to be able to save a voice recording that the user records into RTDB. These voice recordings will be interweaved with text-based messages (it's a group chat app), i.e. users can either send a regular text message or send a voice recording. How do I modify my message model + the code to save a record to RTDB to accomplish this? Is it even possible to save an audio file into RTDB?


class Message { //text messages only
  final String uid;
  final String text;
  final DateTime timestamp;
  final String type; 

    required this.uid,
    required this.text,
    required this.timestamp,
    required this.type,

  Message.fromJson(Map<dynamic, dynamic>? json): //Transform JSON into Message
        uid = json?['uid'] as String,
        text = json?['text'] as String,
        timestamp = DateTime.parse(json?['timestamp'] as String),
        type = json?['type'] as String;

  Map<dynamic, dynamic> toJson() => <dynamic, dynamic>{ //Transforms Message into JSON
    'uid': uid,
    'text': text,
    'timestamp': timestamp.toString(),
    'type': type,



class MessageDao {

  MessageDao({required this.groupIDPath}): _messagesRef = FirebaseDatabase.instance.reference().child(groupIDPath);

  String groupIDPath; 
  DatabaseReference _messagesRef;

  //Save a single message to the appropriate node based on groupIDPath
  void saveMessage(Message message) {
  rest of code...


The Firebase Realtime Database can only store JSON types. Storing audio files in the Realtime Database is going to be highly inefficient, as you'd need to convert them to a JSON type (typically base64).

I recommend instead storing the files itself in Cloud Storage, for which there's also a Firebase SDK, and then store a reference to that file (for example its download URL) in the Realtime Database.

To learn more about this, see the documentation on uploading files and getting the download URL.