GPT Image 2 API Reference | Nano Banana Pro API

GPT Image 2

GPT Image 2 for photoreal quality, precise text rendering, and pixel-level editing

Endpoint: POST /api/v1/images/generate
model: gpt-image-2
Output: Image
Credits: from 3

Submit a task

POST/api/v1/images/generate

Parameters

modelstringRequired
Must be "gpt-image-2"
typestringOptionalDefault text-to-image
"text-to-image" or "image-to-image" (default: text-to-image)
text-to-imageimage-to-image
promptstringRequired
Text description (3–20000 chars)
image_urlsstring[]Optional
Required for image-to-image. Up to 4 reference image URLs
input_imagestringOptional
Deprecated. Alias for image_urls[0]
image_sizestringOptional
Optional aspect ratio: "1:1", "16:9", "9:16", "4:3", "3:4", "3:2", "2:3", "5:4", "4:5", "2:1", "1:2", "21:9", or "9:21". Required for 4k; auto/default is not allowed with 4k.
1:116:99:164:33:43:22:35:44:52:11:221:99:21
resolutionstringOptionalDefault 1k
Optional output resolution: "1k", "2k", or "4k" (default: "1k")
1k2k4k
num_imagesnumberOptional
Must be 1 (gpt-image-2 always returns a single image)

Request

curl -X POST https://www.bananapro.site/api/v1/images/generate \
  -H "Authorization: Bearer sk-your-api-key" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "gpt-image-2",
    "resolution": "2k",
    "prompt": "A hand-drawn illustrated greeting card with the text \"Hello, world!\" in serif letters"
  }'

Response200

JSON

{
  "success": true,
  "data": {
    "task_id": "task_gpt2_123",
    "credits_used": 4,
    "remaining_credits": 496,
    "model": "gpt-image-2"
  }
}

The credits_used values shown in these examples are illustrative. Actual usage is calculated when you submit and returned by the API.

Query the task

GET/api/v1/images/{task_id}

status

pending: Accepted and waiting to start. Keep polling.
processing: Running. Keep polling.
completed: Finished. Read image_url; output holds the full result.
failed: Ended without a result. error_message says why and credits_refunded shows what was returned.

Poll every 5 to 10 seconds and stop at completed or failed, or register a webhook to be notified instead. Failed tasks are refunded automatically.

Request

curl https://www.bananapro.site/api/v1/images/task_abc123 \
  -H "Authorization: Bearer sk-your-api-key"

Response200

JSON

{
  "success": true,
  "data": {
    "task_id": "task_abc123",
    "model": "gpt-image-2",
    "status": "completed",
    "output": { "images": [{ "url": "https://..." }] },
    "primary_url": "https://...",
    "image_url": "https://...",
    "error_message": null,
    "credits_used": 4,
    "credits_refunded": 0,
    "created_at": "2026-10-04T10:00:00.000Z",
    "updated_at": "2026-10-04T10:01:12.000Z",
    "completed_at": "2026-10-04T10:01:12.000Z"
  },
  "request_id": "req_abc123"
}

Wait for the result

TASK_ID=task_abc123
while true; do
  TASK=$(curl -s https://www.bananapro.site/api/v1/images/$TASK_ID \
    -H "Authorization: Bearer sk-your-api-key")
  STATUS=$(echo "$TASK" | jq -r '.data.status')
  if [ "$STATUS" = "completed" ] || [ "$STATUS" = "failed" ]; then
    echo "$TASK" | jq
    break
  fi
  sleep 10
done

Pricing

Resolution	Credits
1k	3
2k	4
4k	5

Features

Text-to-image generation
Image-to-image editing with up to 4 reference images
Photoreal quality and precise typography
Single-image output (n=1)

curl -X POST https://www.bananapro.site/api/v1/images/generate \ -H "Authorization: Bearer sk-your-api-key" \ -H "Content-Type: application/json" \ -d '{ "model": "gpt-image-2", "resolution": "2k", "prompt": "A hand-drawn illustrated greeting card with the text \"Hello, world!\" in serif letters" }'

{ "success": true, "data": { "task_id": "task_abc123", "model": "gpt-image-2", "status": "completed", "output": { "images": [{ "url": "https://..." }] }, "primary_url": "https://...", "image_url": "https://...", "error_message": null, "credits_used": 4, "credits_refunded": 0, "created_at": "2026-10-04T10:00:00.000Z", "updated_at": "2026-10-04T10:01:12.000Z", "completed_at": "2026-10-04T10:01:12.000Z" }, "request_id": "req_abc123" }

TASK_ID=task_abc123 while true; do TASK=$(curl -s https://www.bananapro.site/api/v1/images/$TASK_ID \ -H "Authorization: Bearer sk-your-api-key") STATUS=$(echo "$TASK" | jq -r '.data.status') if [ "$STATUS" = "completed" ] || [ "$STATUS" = "failed" ]; then echo "$TASK" | jq break fi sleep 10 done

Resolution

Credits