AI Video Generation in 2026 — Runway, Sora, and Kling API Guide for Developers

import httpx
import time
import os
 
RUNWAY_API_KEY = os.environ["RUNWAY_API_KEY"]
 
def generate_video(
    prompt: str,
    duration: int = 5,  # 5 or 10 seconds
    ratio: str = "1280:768",  # "1280:768", "768:1280", "1104:832"
    seed: int = None
) -> str:
    """Submit a text-to-video job and return the video URL."""
    
    headers = {
        "Authorization": f"Bearer {RUNWAY_API_KEY}",
        "X-Runway-Version": "2024-11-06",
        "Content-Type": "application/json"
    }
    
    payload = {
        "model": "gen3a_turbo",
        "promptText": prompt,
        "duration": duration,
        "ratio": ratio,
    }
    if seed is not None:
        payload["seed"] = seed
    
    # Submit job
    response = httpx.post(
        "https://api.dev.runwayml.com/v1/image_to_video",
        json=payload,
        headers=headers
    )
    response.raise_for_status()
    task_id = response.json()["id"]
    
    # Poll for completion
    for _ in range(120):  # Max 10 minutes
        status_resp = httpx.get(
            f"https://api.dev.runwayml.com/v1/tasks/{task_id}",
            headers=headers
        )
        task = status_resp.json()
        
        if task["status"] == "SUCCEEDED":
            return task["output"][0]  # Video URL
        elif task["status"] == "FAILED":
            raise RuntimeError(f"Video generation failed: {task.get('failure')}")
        
        time.sleep(5)
    
    raise TimeoutError("Video generation timed out")

def image_to_video(
    image_url: str,
    motion_prompt: str,
    duration: int = 5
) -> str:
    """Animate an existing image with a motion description."""
    
    headers = {
        "Authorization": f"Bearer {RUNWAY_API_KEY}",
        "X-Runway-Version": "2024-11-06"
    }
    
    payload = {
        "model": "gen3a_turbo",
        "promptImage": image_url,
        "promptText": motion_prompt,
        "duration": duration,
        "ratio": "1280:768"
    }
    
    response = httpx.post(
        "https://api.dev.runwayml.com/v1/image_to_video",
        json=payload,
        headers=headers
    )
    # ... same polling pattern

import fal_client
import os
 
os.environ["FAL_KEY"] = "fal-..."
 
def kling_generate(
    prompt: str,
    duration: str = "5",  # "5" or "10"
    aspect_ratio: str = "16:9"
) -> str:
    """Generate video with Kling via fal.ai."""
    
    result = fal_client.subscribe(
        "fal-ai/kling-video/v1.6/standard/text-to-video",
        arguments={
            "prompt": prompt,
            "duration": duration,
            "aspect_ratio": aspect_ratio,
            "negative_prompt": "blurry, distorted, watermark"
        }
    )
    
    return result["video"]["url"]

A coffee cup on a table

A ceramic coffee cup sits on a wooden table. Steam rises slowly from the cup.
Camera slowly pushes in. Warm morning light. Cinematic.

[Subject and setting] [motion/action] [camera movement] [lighting] [style]

prompts = {
    "product_demo": (
        "A sleek smartphone on a white surface. "
        "The phone slowly rotates 360 degrees. "
        "Studio lighting. Clean product photography style."
    ),
    "hero_animation": (
        "An abstract network of glowing blue nodes and connections "
        "expanding outward from center. "
        "Camera pulls back slowly. "
        "Dark background. Technology aesthetic."
    ),
    "data_visualization": (
        "A 3D bar chart growing from zero as data loads. "
        "Blue and white color scheme. "
        "Clean, minimal, corporate animation style."
    )
}

import httpx
import boto3
import uuid
 
async def generate_and_store(prompt: str, bucket: str) -> str:
    """Generate a video and upload to S3."""
    video_url = generate_video(prompt)
    
    # Download
    response = httpx.get(video_url)
    video_data = response.content
    
    # Upload to S3
    key = f"videos/{uuid.uuid4()}.mp4"
    s3 = boto3.client("s3")
    s3.put_object(
        Bucket=bucket,
        Key=key,
        Body=video_data,
        ContentType="video/mp4"
    )
    
    return f"https://{bucket}.s3.amazonaws.com/{key}"