Introduction
It runs Prefect Pony XL, a community SDXL checkpoint merge from the Pony Diffusion lineage, and adds a LoRA slot, a guidance control and nine native SDXL aspect ratios.
Related page
Prefect Pony XL without a LoRA slot has its own page: Prefect Pony XL.
Key features
Pony-family LoRAs by direct link
The Pony ecosystem has a deep library of style and character LoRAs. Pass the direct link to a .safetensors file and a scale; nothing is uploaded to us in advance, and the file is not reviewed.
Three at once
Up to three LoRAs per request, each with its own scale. In our test three stacked at 0.8, 0.5 and 0.3 loaded together and the main style still read clearly.
Native SDXL shapes
Nine aspect ratios, each mapped to a native SDXL size from 1024 x 1024 to 1536 x 640. In our tests every one came back at exactly the requested size.
Request parameters
| Parameter | Required | Description |
|---|---|---|
aspect_ratio | No | The shape of the frame: wide, square or tall. 1:1 · 16:9 · 9:16 · 4:3 · 3:4 · 3:2 · 2:3 · 21:9 · 9:21 · Default: 1:1 |
guidance_scale | No | How strictly the model follows the prompt. ≥ 1 · ≤ 20 · Default: 3.5 |
loras | No | Load your own LoRA files to lock in a style or character. Default: [] |
output_format | No | File type of the result. jpeg · png · webp · Default: jpeg |
prompt | Yes | Comma-separated tags with score tags first. Put LoRA trigger words at the start. |
seed | No | Reuse the same number to get a repeatable result. ≥ 0 · ≤ 2147483647 |
Pricing
Prices are in credits, the same credits you use on the website (1 credit = $0.01). The hold is taken when the task is accepted and settled to the actual charge when it finishes; failed tasks are refunded.
| Option | Credits per image | ≈ USD |
|---|---|---|
| Standard | 3.6 | $0.036 |
Each task is rounded up to whole credits, so one run at the lowest tier costs 4 credits per image ($0.04).
For an exact number before you run, send the same body to POST /jobs/quote.
Use cases
A house style for a whole set
Load a style LoRA, keep the trigger words at the front and run a list of prompts. Every image in the set shares the look.
Consistent characters
Keep a character LoRA and a seed fixed, then change only the outfit, place and light between prompts.
Prompt guide & pro tips
Score tags first
Start with score_9, score_8_up, score_7_up, then a source tag such as source_anime, a rating tag, the head count (1girl, 1boy) and the subject. Put each LoRA's trigger words at the very front.
Compare against no LoRA
Run the same prompt and seed without the LoRA. If the two images are identical, the file was trained for another base model: such LoRAs load without an error and do nothing.
Guidance around 3.5 to 7
The default 3.5 is balanced. In our tests 7 gave more contrast and saturation, 12 burnt the colours, and 1 came out washed out.
API quick start
Call the Prefect Pony XL LoRA API in three steps
- Create an API key. Sign in to PopNow and create a key in the API console. Keys start with sk-popnow- and use the same credits as the website.
- Send the request. POST /jobs/createTask with model prefect/pony-xl-lora/text-to-image and an input object that follows the parameter table. The response returns a task ID straight away.
- Get the result. Poll GET /jobs/recordInfo with the task ID, or pass a callBackUrl and we post the result to it. Download the output links when the task succeeds.
# 1. Create the task. Keep the Idempotency-Key if you retry after a network error.
export IDEMPOTENCY_KEY="$(uuidgen)"
curl -X POST https://api.popnow.ai/api/v1/jobs/createTask \
-H "Authorization: Bearer $POPNOW_API_KEY" \
-H "Content-Type: application/json" \
-H "Idempotency-Key: $IDEMPOTENCY_KEY" \
-d '{
"model": "prefect/pony-xl-lora/text-to-image",
"input": {
"prompt": "A ceramic teapot on a linen cloth, soft window light, muted palette",
"aspect_ratio": "1:1",
"output_format": "jpeg"
}
}'
# 2. Copy data.taskId from the response, then poll until state is succeeded, failed, canceled or expired.
TASK_ID="TASK_ID_FROM_RESPONSE"
curl "https://api.popnow.ai/api/v1/jobs/recordInfo?taskId=$TASK_ID" \
-H "Authorization: Bearer $POPNOW_API_KEY"Replace the prompt and any links with your own. The API tab has the response, polling and callback reference.
Prefect Pony XL LoRA API questions
How much does the Prefect Pony XL LoRA API cost?
Prefect Pony XL LoRA costs 4 credits ($0.04) per image. Credits are the same as on the website (1 credit = $0.01), new accounts get 30 free credits, and failed tasks are refunded.
What is the model name for Prefect Pony XL LoRA in the API?
Put prefect/pony-xl-lora/text-to-image for Create Image in the model field of POST /jobs/createTask.
Which LoRAs work here?
Files trained for Pony-family SDXL checkpoints, passed as a direct download link to the .safetensors file. LoRAs made for other bases such as Z-Image, FLUX or Anima do not transfer: in our test one loaded without an error and changed nothing.
How is this different from Prefect Pony XL?
This endpoint adds a LoRA slot, a guidance control and nine aspect ratios. The Prefect Pony XL page offers Prefect Pony XL without a LoRA slot. Both prompt the same way, with score tags first.
Why only nine sizes?
SDXL checkpoints are trained on a fixed set of shapes around one megapixel. In our tests larger sizes drew duplicated people, so the endpoint exposes the native sizes only.
What are the limits of the Prefect Pony XL LoRA API?
Aspect ratios: 1:1 · 16:9 · 9:16 · 4:3 · 3:4 · 3:2 +3; Prompt length (characters): 5,000. Requests outside these limits are rejected before anything is charged.
Can I try Prefect Pony XL LoRA without writing code?
Yes. The Playground runs Prefect Pony XL LoRA on your PopNow credits, needs no API key, and shows the matching code for every run.
All Prefect Pony XL models
Prefect Pony XL is the same checkpoint without LoRA slots.


