How to Use the FaceDetect API: face swap integration guide (2026)

FaceDetect is a face swap model by NamiFusion: A face detection model used to detect facial information contained in input elements. On NamiFusion you can try it in the playground (exact quote shown before you submit), then call it through one unified REST API.

TL;DR

· Task type: face swap, provided by NamiFusion

· Pricing: pay-as-you-go credits ($1 = 100 credits), no subscription

· Getting started: playground (exact quote before submit) → create an API key → one POST request

· Tunable parameters: 8 (see the table below)

· No platform watermark; commercial use allowed (per the Terms of Service)

What can you build with FaceDetect?

Film and short-drama post-production: replace faces for reshoots or multi-language localization.

Memes and entertainment: put yourself or friends into iconic scenes — built for social sharing.

Virtual personas and privacy: use a substitute face for streams and on-camera content.

Batch production: map multiple source faces onto the same footage to mass-produce personalized versions.

How do you call this API?

1. Sign up on NamiFusion and create a key on the API Keys page (free credits on signup).

2. Submit a task with the cURL example below, passing your key as a Bearer token.

3. Poll the task status with the returned task_uuid and read the output URLs when completed.

# 1) Submit — returns { "task_uuid": "..." }
curl -X POST "https://www.namifusion.com/api/v1/marketplace/run/namifusion/detect_faces" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "input": {
    "url": "https://assets-public.namifusion.com/marketplace/thumbnails/2026-02-25/fb559d5bc3dc.png",
    "num_frames": 5,
    "return_face_url": true,
    "single_face": false,
    "deduplicate": true,
    "similarity_threshold": 0.45,
    "time_range": {}
  }
}'

# 2) Poll until status is "completed", then read the output URLs
curl "https://www.namifusion.com/api/v1/marketplace/run/tasks/TASK_UUID" \
  -H "Authorization: Bearer YOUR_API_KEY"

What parameters does it take?

url (Media URL): optional

img (Base64 Image): optional

num_frames (Number of Frames): optional, default 5

return_face_url (Return Face URL): optional, default true

single_face (Single Face Only): optional, default false

deduplicate (Deduplicate Faces): optional, default true

similarity_threshold (Similarity Threshold): optional, default 0.45

time_range (Time Range): optional, default {}

How do you write prompts for FaceDetect?

1. Subject first: lead with the actor and action, then add environment, lighting and style ("an astronaut sprinting through a neon street in the rain, cinematic, shallow depth of field").

2. Concrete nouns beat stacked adjectives: "85mm portrait lens, golden-hour backlight" works far better than "very beautiful, ultra high quality".

3. Change one variable per iteration: pin the seed to reproduce a result, tweak a single phrase at a time so you know what actually moved the output.

4. State negatives positively: instead of "no blur", ask for "sharp focus, crisp details".

How much does it cost?

Pay-per-use in credits ($1 = 100 credits). The exact price varies with parameters; the playground shows the quote before you submit.