LTX-2.5 Fast — API reference

LTX-2.5 Fast uses the model ID lightricks/ltx-2.5/image-to-video/fast. LTX-2.5 Fast Image to Video on Runware with native audio and optional camera movement.

1. Calling the API

Send requests to https://api.higgsfield.ai/lightricks/ltx-2.5/image-to-video/fast with a JSON body matching the parameters below.

Install

Install an official server-side SDK. cURL needs no package.

npm install @higgsfield/client

Setup

Keep credentials in server-side environment variables. The SDKs accept the same KEY_ID:KEY_SECRET value under their documented variable names.

export HF_CREDENTIALS="YOUR_KEY_ID:YOUR_KEY_SECRET" # TypeScript
export HF_KEY="YOUR_KEY_ID:YOUR_KEY_SECRET"         # Python and cURL

Request parameters

Parameter	Type	Required	Default	Description
`fps`	`integer`	No	`25`	Frames per second. Options: 24, 25, 48, 50.
`prompt`	`string`	Yes	`—`	Prompt. Minimum length: 2. Maximum length: 5000.
`duration`	`integer`	Yes	`6`	Duration. Options: 6, 8, 10.
`image_url`	`string`	Yes	`—`	First frame.
`resolution`	`string`	No	`"720p"`	Resolution. Options: 720p, 1080p, 2k, 4k.
`aspect_ratio`	`string`	No	`"16:9"`	Aspect ratio. Options: 16:9, 9:16.
`end_image_url`	`string`	No	`—`	Last frame.
`generate_audio`	`boolean`	No	`true`	Generate audio.
`camera_movement`	`string`	No	`—`	Camera movement. Options: dolly_in, dolly_out, dolly_left, dolly_right, jib_up, jib_down, static, focus_shift.

2. Authentication

The official SDKs read credentials from the server environment and send the required Authorization: Key KEY_ID:KEY_SECRET header.

API Key

Never expose the secret in browser-side code or commit it to source control. The TypeScript SDK is server-side only. For direct HTTP calls, use:

Authorization: Key $HF_KEY

3. Queue

subscribe submits the asynchronous request and waits for a terminal result. The TypeScript SDK polls automatically when withPolling: true; the Python SDK's synchronous subscribe call also waits. A completed request returns the generated file in the video field.

Submit and wait

import { config, higgsfield } from "@higgsfield/client/v2";

config({
  credentials: process.env.HF_CREDENTIALS,
});

const result = await higgsfield.subscribe(
  "lightricks/ltx-2.5/image-to-video/fast",
  {
    input: {
      "fps": 25,
      "prompt": "A cinematic scene at sunset",
      "duration": 6,
      "image_url": "https://example.com/input.jpg",
      "resolution": "720p",
      "aspect_ratio": "16:9",
      "generate_audio": true
    },
    withPolling: true,
  },
);

console.log(result);

Explicit lifecycle control

Use the Python SDK when a worker needs explicit status, result, or cancellation control for an existing request. The TypeScript v2 client currently exposes automatic polling through subscribe.

import higgsfield_client

request_id = "{request_id}"
status = higgsfield_client.status(request_id=request_id)
result = higgsfield_client.result(request_id=request_id)
higgsfield_client.cancel(request_id=request_id)