How to Use the Head Swap – Generate API: character swap integration guide (2026)

2 min · Updated 2026-07-11 · By the NamiFusion team

Learn how to call the Head Swap – Generate API on NamiFusion: parameters, pricing (from ≈$0.750) and runnable copy-paste code — try it in the playground first.

Head Swap – Generate is a character swap model by NamiFusion: Replace selected heads in the video with your reference images using Wan2.2-Animate. Keeps the original audio track. On NamiFusion you can try it in the playground (exact quote shown before you submit), then call it through one unified REST API — about $0.750 per typical run.

TL;DR

· Task type: character swap, provided by NamiFusion

· Pricing: about $0.750 per typical run ($1 = 100 credits), pay-as-you-go

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

· Tunable parameters: 4 (see the table below)

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

What can you build with Head Swap – Generate?

Content automation: wire this model into your workflow and call it on demand through one unified API.

How do you call this API?

Sign up on NamiFusion and create a key on the API Keys page (signup bonus credits can only be used on selected models).
Submit a task with the cURL example below, passing your key as a Bearer token.
Poll the task status with the returned task_uuid and read the output URLs when completed.

Submit a task

# 1) Submit — returns { "task_uuid": "..." }
curl -X POST "https://www.namifusion.com/api/v1/marketplace/run/namifusion/head-swap/generate" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "input": {
    "track_manifest_url": "ANALYZE_OUTPUT.track_manifest_url",
    "mappings": [
      {
        "obj_id": 0,
        "img_urls": [
          "https://assets-public.namifusion.com/marketplace/images/2026-06-12/638e1ee18ac7.jpeg"
        ]
      }
    ],
    "resolution": "720p"
  }
}'

# 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?

track_manifest_url (Track manifest URL): required

mappings (Head mappings): required

resolution (Resolution): optional, default "720p"

seed (Seed): optional

How much does it cost?

Pay-per-use in credits. About $0.750 per typical run ($1 = 100 credits); the exact price varies with parameters like resolution or duration, and the playground shows the exact quote before you submit.

Head Swap – Generate

Replace selected heads in an analyzed video with reference images while preserving the original audio.

Head Swap Generate is the second stage of the Head Swap workflow. Each item in mappings associates an Analyze obj_id with one to three reference image URLs, making the replacement target explicit. The video_url and track_manifest_url must come from the same Analyze task, and the generation resolution must match the analysis resolution.

Key Features

Explicit per-head selection: Uses the obj_id from Analyze to avoid replacing the wrong target.
Multiple-target mappings: Assign separate reference images to several heads in one video.
Multiple reference images: Supply one to three images per target to cover appearance and viewing-angle details.
Original audio preservation: Keeps the input video's audio track in the completed output.
480p and 720p output: Select the quality tier that matches the intended result and existing pricing band.

Technical Specifications

Item	Details
Workflow	Head Swap step 2
Required inputs	`video_url`, `track_manifest_url`, `mappings`
`mappings` format	Array of `{obj_id, img_urls}` objects
Reference images	1-3 URLs per target
Resolution	`480p`, `720p` (default)
Maximum video length	30 seconds
Optional input	`seed`
Output	Video URL with the original audio preserved

Basic Workflow

Process the input video with Head Swap Analyze.
Select the target obj_id values from the previews in objects.
Pair each ID with its head reference image URLs in mappings.
Submit the same video and returned Analyze manifest, then poll until generation completes.

Full parameter reference, output schema & live pricing →

FAQ

Can I try it for free first?+

Signup bonus credits can only be used on selected models, and eligibility may change. The playground shows the exact quote before submission.

Can I use the output commercially? Is there a watermark?+

Yes, outputs are yours to use commercially, and NamiFusion adds no platform watermark — subject to the Terms of Service and applicable law.

What is the content policy?+

Pornographic content, sexualized content involving a minor, unauthorized use of real people, deceptive impersonation, fraud and false endorsements are prohibited. Lawful, consensual, non-explicit adult themes may be permitted; see the Terms of Service.

How long does a Head Swap – Generate task take?+

It depends on parameters — images usually take seconds, videos tens of seconds to minutes. The API returns a task_uuid for polling.

What are the resolution and duration limits?+

See the parameter table above — each model lists its available resolution and duration options there and in the playground.

Try it free →