Image generation API: GPT Image 2, Nano Banana and Seedream

Send a prompt (and optionally reference images) to one endpoint and choose the model with a single field: GPT Image 2, Seedream 5 Pro, Nano Banana, Imagen 4 and others. Image jobs run as tasks you poll or receive by webhook, and you pay only for finished images.

Who it is for

Product teams generating marketing images, thumbnails or product shots
Apps that let users create or edit images
Developers comparing image models without opening several accounts

How it works

POST the prompt, model and options; you get a task id back at once.
Poll GET /v1/tasks/{id} every few seconds, or pass webhook_url to be notified.
When status is done, output.images holds the image URLs and credit.charged_usd shows the charge.

Endpoints

Method	Path	What it does
`POST`	`/v1/images/generations`	Start an image task
`GET`	`/v1/tasks/{id}`	Poll the task for the image URLs

Models

Pass one of these as model (or voice_id for voices). The full, current list with prices is at /v1/models.

ai33/gpt-image-2
ai33/bytedance-seedream-5-pro
kie/google/nano-banana
kie/google/imagen4
kie/gpt-image-2-text-to-image

Example

curl https://omni-api.rcinc.app/v1/images/generations \
  -H "Authorization: Bearer $OMNI_KEY" -H "content-type: application/json" \
  -d '{"model":"ai33/gpt-image-2","prompt":"A lighthouse at dusk, watercolor","aspect_ratio":"16:9","resolution":"2K"}'

# -> {"id":"task_…","status":"pending"}; then GET https://omni-api.rcinc.app/v1/tasks/task_…

Pricing

Charged per finished image. GPT Image 2 at 1K costs about $0.007 on Omni against $0.219 at OpenAI's list price; Nano Banana costs $0.023 against Google's $0.039. Failed tasks cost nothing. See the pricing page for the full comparison.

Limits

Image links expire after a while, so download results promptly.
Reference images must be public HTTPS links of up to 5 MB each.
Generation usually takes seconds but can take longer when a model's queue is busy.