Imagen 4 Fast

Google Imagen 4 fast tier — quickest gen, lower fidelity. Cheapest Imagen on Kyma at $0.027/image. Sync API, blob-hosted output.

Overview

imagen-4-fast is Google’s fastest Imagen 4 variant — optimised for quick drafts, social previews, and rapid iteration over hero-fidelity work. Sync API on Vertex AI, blob-hosted output, no async polling.

Lives in the same family as imagen-4 (default) and imagen-4-ultra (premium). Pick by latency + cost; the underlying style language is the same.

Specs

Field	Value
Model ID	imagen-4-fast
Creator	Google
Backend	Vertex AI (imagen-4.0-fast-generate-001, us-central1)
Best for	Drafts, social previews, rapid iteration
Aspect ratios	1:1 (default), 3:4, 4:3, 16:9, 9:16
Sample count n	1–4
Pricing mode	Flat per image
Default latency	~5–10s
Output	Blob-hosted URL (Vercel CDN)

Pricing

Flat per-image. List = provider cost × 1.35.

Variant	Provider cost	Kyma list
imagen-4-fast	$0.020	$0.027

Live source: GET https://kymaapi.com/v1/pricing.

Compared to other image models on Kyma

Strength	imagen-4-fast	imagen-4	imagen-4-ultra	nano-banana
Cheapest Imagen	★★★★★	★★★★	★★	n/a
Photoreal humans	★★★	★★★★	★★★★★	★★★
Print fidelity	★★	★★★★	★★★★★	★★
Speed	★★★★★	★★★★	★★★	★★★★★
Edit-mode	—	—	—	yes

Use this when

• You need many quick drafts to iterate prompts cheaply.
• The output is a social preview, draft mockup, or low-resolution asset.
• Speed beats fidelity.

Pick something else when

• You need photoreal hero output → imagen-4 or imagen-4-ultra.
• You need to edit an existing image (image-in, prompt-driven) → nano-banana.
• You need legible text-in-image → gpt-image-2 (high tier).

Example

curl -X POST https://kymaapi.com/v1/images/generations \
  -H "Authorization: Bearer $KYMA_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "imagen-4-fast",
    "prompt": "A minimalist Scandinavian living room with morning light, soft pastels",
    "size": "16:9",
    "n": 1
  }'

The endpoint is async — POST returns 202 with a job_id; poll GET /v1/jobs/{id} until status is succeeded. The completed job’s output.url is a Vercel blob URL on Kyma’s CDN.