AI image upscaler 8x: what Sume's upscale API allows

Not 8x. Sume's Image Upscale 1.0 (POST /v1/image-upscale-1.0/upscale) takes an upscale_factor from 1 to 4, default 2, and its schema is strict, so a factor of 8 is rejected as an invalid request rather than clamped. The price is one flat rate per image.

From the OpenAPI document behind the Sume API reference and the API reference docs, read 2026-09-29.

What does the upscaler accept?

curl -X POST https://api.sume.com/v1/image-upscale-1.0/upscale \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: upscale-4x-001" \
  -d '{
    "image_url": "https://example.com/photo.png",
    "upscale_factor": 4,
    "output_format": "png"
  }'

How much does an upscale cost?

API pricing lists Image Upscale at $0.20 per image. Sume reserves the estimate on submit and refunds a job that fails or is canceled before capture.

What if I need more than 4x?

The docs do not describe repeating the upscaler on its own output, so this post does not promise it works. Two options the docs do support: generate at a larger size in the first place (resolution up to 4K on the Nano Banana models), or resize in your own tool after upscaling. Generate at 4K or upscale? compares the two costs.

Does a bigger factor change the price?

The rate card shows one per-image price and no factor tiers.