Cheapest Nano Banana API for YouTube Thumbnails, Character Sheets & Keyframes

// Node.js 18+ / TypeScript: Generate 4 16:9 YouTube thumbnail variants for A/B testing
const BASE = 'https://avatarity.dev';
const API_KEY = process.env.AVATARITY_API_KEY!;

export async function generateThumbnailVariants(params: {
  titleConcept: string;
  hostReferenceUrls: string[];
  videoId: string;
}): Promise<string[]> {
  const res = await fetch(`${BASE}/v1/images/generations`, {
    method: 'POST',
    headers: {
      Authorization: `Bearer ${API_KEY}`,
      'Content-Type': 'application/json',
      'Idempotency-Key': `yt-thumb-${params.videoId}`,
    },
    body: JSON.stringify({
      model: 'nano-banana-pro',
      prompt: params.titleConcept,
      n: 4,
      aspect_ratio: '16:9',
      reference_images: params.hostReferenceUrls.slice(0, 4),
    }),
  });

  const body = await res.json();
  if (!res.ok) {
    throw new Error(`Nano Banana error ${body?.error?.code ?? res.status}: ${body?.error?.message ?? ''}`);
  }

  return (body.data as Array<{ url: string }>).map((item) => item.url);
}

import os, uuid, requests

BASE = "https://avatarity.dev"
HEADERS = {
    "Authorization": f"Bearer {os.environ['AVATARITY_API_KEY']}",
    "Content-Type": "application/json",
}

def generate_consistent_scene_keyframe(prompt: str, character_refs: list[str], aspect_ratio: str = "16:9") -> str:
    """Synthesize a photorealistic scene keyframe locked to up to 4 character reference images."""
    resp = requests.post(
        f"{BASE}/v1/images/generations",
        headers={**HEADERS, "Idempotency-Key": str(uuid.uuid4())},
        json={
            "model": "nano-banana-2.1",
            "prompt": prompt,
            "n": 1,
            "aspect_ratio": aspect_ratio,
            "reference_images": character_refs[:4],
        },
        timeout=90,
    )
    resp.raise_for_status()
    return resp.json()["data"][0]["url"]