Generate videos by animating between a first and last frame using Google's Veo 3.1 Lite model.
A lightweight, cost-effective variant of Veo 3.1.
The model supports:
Safety filters are applied to both input images and generated content.
The client provides a convenient way to interact with the model API.
npm install --save @fal-ai/clientThe @fal-ai/serverless-client package has been deprecated in favor of @fal-ai/client. Install the new package and update your imports — see client setup.
Set FAL_KEY as an environment variable in your runtime.
export FAL_KEY="YOUR_API_KEY"The client API handles the API submit protocol. It will handle the request status updates and return the result when the request is completed.
import { fal } from "@fal-ai/client";
const result = await fal.subscribe("fal-ai/veo3.1/lite/first-last-frame-to-video", {
input: {
prompt: "A smooth transition between the two frames with natural motion.",
first_frame_url: "https://storage.googleapis.com/falserverless/example_inputs/veo31-flf2v-input-1.jpeg",
last_frame_url: "https://storage.googleapis.com/falserverless/example_inputs/veo31-flf2v-input-2.jpeg"
},
logs: true,
onQueueUpdate: (update) => {
if (update.status === "IN_PROGRESS") {
update.logs.map((log) => log.message).forEach(console.log);
}
},
});
console.log(result.data);
console.log(result.requestId);The API uses an API Key for authentication. It is recommended you set the FAL_KEY environment variable in your runtime when possible.
import { fal } from "@fal-ai/client";
fal.config({
credentials: "YOUR_FAL_KEY"
});When running code on the client-side (e.g. in a browser, mobile app or GUI applications), make sure to not expose your FAL_KEY. Instead, use a server-side proxy to make requests to the API. For more information, check out our server-side integration guide.
The client API provides a convenient way to submit requests to the model.
import { fal } from "@fal-ai/client";
const { request_id } = await fal.queue.submit("fal-ai/veo3.1/lite/first-last-frame-to-video", {
input: {
prompt: "A smooth transition between the two frames with natural motion.",
first_frame_url: "https://storage.googleapis.com/falserverless/example_inputs/veo31-flf2v-input-1.jpeg",
last_frame_url: "https://storage.googleapis.com/falserverless/example_inputs/veo31-flf2v-input-2.jpeg"
},
webhookUrl: "https://optional.webhook.url/for/results",
});You can fetch the status of a request to check if it is completed or still in progress.
import { fal } from "@fal-ai/client";
const status = await fal.queue.status("fal-ai/veo3.1/lite/first-last-frame-to-video", {
requestId: "764cabcf-b745-4b3e-ae38-1200304cf45b",
logs: true,
});Once the request is completed, you can fetch the result. See the Output Schema for the expected result format.
import { fal } from "@fal-ai/client";
const result = await fal.queue.result("fal-ai/veo3.1/lite/first-last-frame-to-video", {
requestId: "764cabcf-b745-4b3e-ae38-1200304cf45b"
});
console.log(result.data);
console.log(result.requestId);Some attributes in the API accept file URLs as input. Whenever that's the case you can pass your own URL or a Base64 data URI.
You can pass a Base64 data URI as a file input. The API will handle the file decoding for you. Keep in mind that for large files, this alternative although convenient can impact the request performance.
You can also pass your own URLs as long as they are publicly accessible. Be aware that some hosts might block cross-site requests, rate-limit, or consider the request as a bot.
We provide a convenient file storage that allows you to upload files and use them in your requests. You can upload files using the client API and use the returned URL in your requests.
import { fal } from "@fal-ai/client";
const file = new File(["Hello, World!"], "hello.txt", { type: "text/plain" });
const url = await fal.storage.upload(file);The client will auto-upload the file for you if you pass a binary object (e.g. File, Data).
Read more about file handling in our file upload guide.
prompt string* requiredThe text prompt describing the video you want to generate
aspect_ratio AspectRatioEnumThe aspect ratio of the generated video. Default value: "auto"
Possible enum values: auto, 16:9, 9:16
duration DurationEnumThe duration of the generated video. Default value: "8s"
Possible enum values: 4s, 6s, 8s
negative_prompt stringA negative prompt to guide the video generation.
resolution ResolutionEnumThe resolution of the generated video. Default value: "720p"
Possible enum values: 720p, 1080p
generate_audio booleanWhether to generate audio for the video. Default value: true
seed integerThe seed for the random number generator.
auto_fix booleanWhether to automatically attempt to fix prompts that fail content policy or other validation checks by rewriting them.
safety_tolerance SafetyToleranceEnumThe safety tolerance level for content moderation. 1 is the most strict (blocks most content), 6 is the least strict. Default value: "4"
Possible enum values: 1, 2, 3, 4, 5, 6
Note: This property is only available through API calls.
first_frame_url string* requiredURL of the first frame of the video
last_frame_url string* requiredURL of the last frame of the video
{
"prompt": "A smooth transition between the two frames with natural motion.",
"aspect_ratio": "auto",
"duration": "8s",
"resolution": "720p",
"generate_audio": true,
"safety_tolerance": "4",
"first_frame_url": "https://storage.googleapis.com/falserverless/example_inputs/veo31-flf2v-input-1.jpeg",
"last_frame_url": "https://storage.googleapis.com/falserverless/example_inputs/veo31-flf2v-input-2.jpeg"
}The generated video.
{
"video": {
"url": "",
"content_type": "image/png",
"file_name": "z9RV14K95DvU.png",
"file_size": 4404019
}
}url string* requiredThe URL where the file can be downloaded from.
content_type stringThe mime type of the file.
file_name stringThe name of the file. It will be auto-generated if not provided.
file_size integerThe size of the file in bytes.