Generation Tools

Model Swap

Swap the person's identity in an existing on-model photo while keeping the outfit, pose and scene unchanged — show the same product on a different model without a new photoshoot.

toolId: "model_swap" 4 credits model_garment ratio: ignored

Model Swap result — the same outfit and pose on a different model identity

What it does

Point this at an existing on-model photo and a new identity, and Fashio replaces just the person — the outfit, pose, framing and background all carry over unchanged. It's the tool to reach for when you need to show one product on several different models without re-shooting or re-generating the scene from scratch.

Like Pose Variation, this is an in-place edit: the original frame and outfit are preserved, only who's wearing it changes. ratio is ignored if sent.

Request body

Field	Type		Description
`toolId`	string	required	Always `"model_swap"`.
`images.user_photo`	string	required	URL of the existing on-model photo whose person will be replaced.
`images.fashion_model`	string	required	A catalog ID from GET /v1/fashion-models, or a direct image URL, of the new identity to swap in.

Example request

curl -X POST https://api.fashiolabs.com/v1/generations \
  -H "Authorization: Bearer fio_live_YOUR_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "toolId": "model_swap",
    "images": {
      "user_photo": "https://your-cdn.com/on-model-shot.jpg",
      "fashion_model": "fm_south_asian_01"
    }
  }'

const res = await fetch("https://api.fashiolabs.com/v1/generations", {
  method: "POST",
  headers: {
    Authorization: "Bearer " + process.env.FASHIO_API_KEY,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    toolId: "model_swap",
    images: {
      user_photo: "https://your-cdn.com/on-model-shot.jpg",
      fashion_model: "fm_south_asian_01",
    },
  }),
});
const { id } = await res.json();

import os, requests

res = requests.post(
    "https://api.fashiolabs.com/v1/generations",
    headers={"Authorization": f"Bearer {os.environ['FASHIO_API_KEY']}"},
    json={
        "toolId": "model_swap",
        "images": {
            "user_photo": "https://your-cdn.com/on-model-shot.jpg",
            "fashion_model": "fm_south_asian_01",
        },
    },
)
job_id = res.json()["id"]

Response

202 Accepted{ "success": true, "id": "8b1e...", "status": "processing" }

Poll GET /v1/generations/:id (see Quickstart) until it completes:

200 · completed{
  "success": true,
  "id": "8b1e...",
  "status": "completed",
  "resultUrls": ["https://.../result.jpg"],
  "errorMessage": null
}

Common errors

Status	Meaning
400	`model_swap: missing required image "user_photo"` — required image field wasn't resolvable.
402	`Insufficient diamonds. Required 4, have <n>.`
429	Daily request cap reached for this key — see Rate Limits.

Pose Variation — change how the person is posed instead of who they are.
Virtual Try-On (Single) — generate a fresh on-model photo from a garment instead of editing an existing one.