Runway Act 2 Image to Video API: AI Image-to-Video

Runway Act 2 Image to Video API Reference

Endpoint

POST https://api.muapi.ai/api/v1/runway-act-two-i2v

Submit a job with your MuApi API key in the x-api-key header, then poll https://api.muapi.ai/api/v1/predictions/{request_id}/result until status is completed.

Parameters

Name	Type	Required	Description
image_url	string	Yes	URL of the input image. An image of your character. In the output, the character will use the reference video performance in its original static environment.
reference_video_url	string	Yes	A video URL pointing to a video of a person performing in the manner that you would like your character to perform.
aspect_ratio	string	No	Aspect ratio of the output video.Options: 16:9, 9:16, 1:1, 4:3, 3:4, 21:9Default: "16:9"

cURL example

REQUEST_ID=$(curl -s -X POST https://api.muapi.ai/api/v1/runway-act-two-i2v \
  -H "x-api-key: $MUAPI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"image_url":"https://example.com/your-image_url","reference_video_url":"https://example.com/your-reference_video_url"}' | jq -r .request_id)

curl -s https://api.muapi.ai/api/v1/predictions/$REQUEST_ID/result -H "x-api-key: $MUAPI_API_KEY"

Python example

import os, time, requests

API = "https://api.muapi.ai/api/v1"
headers = {"x-api-key": os.environ["MUAPI_API_KEY"]}

r = requests.post(f"{API}/runway-act-two-i2v", headers=headers, json={"image_url":"https://example.com/your-image_url","reference_video_url":"https://example.com/your-reference_video_url"})
request_id = r.json()["request_id"]

while True:
    res = requests.get(f"{API}/predictions/{request_id}/result", headers=headers).json()
    if res["status"] == "completed":
        print(res["outputs"]); break
    if res["status"] == "failed":
        raise RuntimeError(res.get("error"))
    time.sleep(3)

Full docs and agent/MCP integration: llms.txt. Get an API key at muapi.ai/access-keys.