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POST
GPT Image 2.5 Ext
gpt-image-2.5-ext is the canonical GPT Image 2.5 Ext route. It bills per delivered image, not by tokens. Flare is the default. Send version: "sunburst" for Sunburst on this model ID, or use gpt-image-2.5-ext-sunburst. 100 FreeModel credits = $1. Flare and Sunburst use the same prices. Reference images have no surcharge. Ext does not accept quality, transparency, or custom pixel sizes such as 1024x1024.
string
required
Set to gpt-image-2.5-ext.
string
required
Describe the subject, composition, lighting, and style. The prompt must be a non-empty string of at most 100,000 characters.
string
default:"flare"
Use flare or sunburst.
string
default:"1K"
Use 1K, 2K, or 4K. This selects the billed output tier.
string
default:"auto"
Use auto, 1:1, 16:9, 9:16, 4:3, 3:4, 3:2, 2:3, 5:4, 4:5, or 21:9.
integer
default:"1"
Request 1 to 4 images. The gateway reserves n times the resolution price, then settles the actual returned count.
string[]
Up to 16 publicly reachable http or https image URLs, or data:image/png, data:image/jpeg, or data:image/webp Data URLs. Loopback, private, and credentialed URLs are rejected. The whole JSON body is still limited by the gateway request-size cap (default 10 MiB).

Request

A normal request waits for a terminal result (default 180 seconds). On success it returns image URLs. If generation is still running, the response is HTTP 202 with a gateway task object. Poll GET /v1/tasks/{id} with the same API key. Do not treat that object as an upstream Apimart payload.

Run asynchronously

Send Prefer: respond-async to receive HTTP 202 immediately. Include Idempotency-Key (1–200 characters) if you need the gateway to replay the same client submission. Read Location or x-gateway-task-id, then poll GET /v1/tasks/{id}.
The gateway reserves the requested n and resolution up front. A successful task charges the delivered image count against that immutable price version. Explicit failure or cancellation releases the reservation. Missing, empty, oversized, or invalid results keep the reservation for reconciliation. Repeated status polls do not charge twice.

Open the model playground

Run the same route from the FreeModel model page.