Client Library for Dart (Flutter)

Introduction

The client for Dart (Flutter) provides a seamless interface to interact with fal.

Installation

First, add the client as a dependency in your project:

flutter pub add fal_client

Features

1. Call an endpoint

Endpoints requests are managed by a queue system. This allows fal to provide a reliable and scalable service.

The subscribe method allows you to submit a request to the queue and wait for the result.

import 'package:fal_client/fal_client.dart';
 
final fal = FalClient.withCredentials("FAL_KEY");
 
final output = await fal.subscribe("fal-ai/flux/dev",
  input: {
    "prompt": "a cat",
    "seed": 6252023,
    "image_size": "landscape_4_3",
    "num_images": 4
  },
  logs: true,
  webhookUrl: "https://optional.webhook.url/for/results",
  onQueueUpdate: (update) { print(update); }
);
print(output.requestId);
print(output.data);

2. Queue Management

You can manage the queue using the following methods:

Submit a Request

Submit a request to the queue using the queue.submit method.

import 'package:fal_client/fal_client.dart';
 
final fal = FalClient.withCredentials("FAL_KEY");
 
final job = await fal.queue.submit("fal-ai/flux/dev",
  input: {
    "prompt": "a cat",
    "seed": 6252023,
    "image_size": "landscape_4_3",
    "num_images": 4
  },
  webhookUrl: "https://optional.webhook.url/for/results"
);
print(job.requestId);

This is useful when you want to submit a request to the queue and retrieve the result later. You can save the request_id and use it to retrieve the result later.

Webhooks

For long-running requests, such as training jobs, you can use webhooks to receive the result asynchronously. You can specify the webhook URL when submitting a request.

Check Request Status

Retrieve the status of a specific request in the queue:

import 'package:fal_client/fal_client.dart';
 
final fal = FalClient.withCredentials("FAL_KEY");
 
final job = await fal.queue.status("fal-ai/flux/dev",
  requestId: "764cabcf-b745-4b3e-ae38-1200304cf45b",
  logs: true
);
print(job.requestId);
print(job.status);

Retrieve Request Result

Get the result of a specific request from the queue:

import 'package:fal_client/fal_client.dart';
 
final fal = FalClient.withCredentials("FAL_KEY");
 
final output = await fal.queue.result("fal-ai/flux/dev",
  requestId: "764cabcf-b745-4b3e-ae38-1200304cf45b"
);
print(output.requestId);
print(output.data);

3. File Uploads

Some endpoints require files as input. However, since the endpoints run asynchronously, processed by the queue, you will need to provide URLs to the files instead of the actual file content.

Luckily, the client library provides a way to upload files to the server and get a URL to use in the request.

import 'package:cross_file/cross_file.dart';
import 'package:fal_client/fal_client.dart';
 
final fal = FalClient.withCredentials("FAL_KEY");
 
final file = XFile("path/to/file");
final url = await fal.storage.upload(file);

4. Streaming

Some endpoints support streaming:

Not implemented yet

This functionality is not available on this client yet.

5. Realtime Communication

For the endpoints that support real-time inference via WebSockets, you can use the realtime client that abstracts the WebSocket connection, re-connection, serialization, and provides a simple interface to interact with the endpoint:

Not implemented yet

This functionality is not available on this client yet.

6. Run

The endpoints can also be called directly instead of using the queue system.

Prefer the queue

We do not recommend this use most use cases as it will block the client until the response is received. Moreover, if the connection is closed before the response is received, the request will be lost.

import 'package:fal_client/fal_client.dart';
 
final fal = FalClient.withCredentials("FAL_KEY");
 
final output = await fal.run("fal-ai/flux/dev",
  input: {
    "prompt": "a cat",
    "seed": 6252023,
    "image_size": "landscape_4_3",
    "num_images": 4
  });
print(output.requestId);
print(output.data);

API Reference

For a complete list of available methods and their parameters, please refer to Dart (Flutter) API Reference documentation (opens in a new tab).

Examples

Check out some of the examples below to see real-world use cases of the client library:

Simple Flutter app using fal image inference: https://pub.dev/packages/fal_client/example (opens in a new tab)

Support

If you encounter any issues or have questions, please visit the GitHub repository (opens in a new tab) or join our Discord Community (opens in a new tab).

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