Music Extender APIExtend & Continue AI Tracks
Continue a finished clip into a longer track. Pass a continue_clip_id with task_type: extend_music, poll for the result, and download — with API keys, free trial credits, pricing, and production-ready docs.
What is the Music Extender API?
It's the same /sonic/create endpoint with task_type: extend_music. Point it at a continue_clip_id from a prior generation, pick a model version, and the API returns a longer track — ready to chain into a full song.
- Continue Any Clip
Pass a
continue_clip_idfrom any finished generation — no re-upload needed.- Chain to Full Length
Feed each extend's clip id into the next to grow a hook into a complete track.
- Same Async Flow
Reuse the create + task polling you already integrated — extend just sets a task_type.
API Examples
Extend a clip into a longer track, then poll for the result.
1curl -X POST 'https://api.musicapi.ai/api/v1/sonic/create' \
2--header 'Authorization: Bearer YOUR_API_KEY' \
3--header 'Content-Type: application/json' \
4--data '{
5 "task_type": "extend_music",
6 "continue_clip_id": "YOUR_CLIP_ID",
7 "mv": "sonic-v5"
8}'Want to re-render the idea in a new genre instead of lengthening it? Use task_type: cover_music on the same endpoint — see the extend & cover guide. Recommended polling interval: 15-25 seconds.
Why Extend Music on MusicAPI?
One task_type
extend_music on a normal create — nothing else to wire up.
Async + Fast
Returns a task id; tracks finish in 1-3 min.
Chainable
Feed each result back in to reach full song length.
Commercial Rights
Use extended tracks in videos, games, and client work.
Music Extender API: Pricing, Free Access & API Keys
Developers continuing tracks usually want three answers: how to test for free, how to get an API key, and how cost scales after the prototype works.
Free trial
Use free credits to test extend_music before choosing a paid plan.
Pricing
Credit-based (each extend is 15 credits). Estimate per-track cost on the pricing page.
API keys
Generate a bearer token in your account, keep it server-side, and call the create and task endpoints.
Ready to Extend Your Tracks?
Continue any clip into a longer song with one task_type. Start free, then scale with predictable credit pricing.
Frequently Asked Questions
Everything you need to know about extending music with the API.
What is a music extender API?
A music extender API continues an existing track to make it longer over REST. With MusicAPI you POST to https://api.musicapi.ai/api/v1/sonic/create with task_type set to extend_music and a continue_clip_id, then poll the task endpoint until the extended track is ready.
How do I extend a song with the API?
POST to /api/v1/sonic/create with task_type extend_music, the continue_clip_id of a clip from a prior generation, and a model version (mv) like sonic-v5. The call returns a task id; poll GET /api/v1/sonic/task/{id} every 15-25 seconds until the status is complete.
Where does the continue_clip_id come from?
It is the clip id returned by a previous generation — for example a create, cover, or an earlier extend call. Any finished clip from your account can be the source you continue from.
Can I turn a short hook into a full-length track?
Yes. Chain extends: take the clip id returned by one extend_music call and feed it as the continue_clip_id of the next. Each pass continues the arrangement, so a 60-second hook can grow into a full track over a few calls.
How much does extending music cost?
Each extend_music call costs 15 credits. Test with free trial credits, estimate per-track cost on the pricing page, and scale as volume grows. Failed upstream tasks are auto-refunded and polling task status is free.
How long does an extend take?
Extending is asynchronous: the create call returns a task id immediately and tracks typically finish in about 1-3 minutes. Poll the task endpoint until the status is complete.
Do extended tracks include commercial rights?
Yes — audio generated through the API comes with commercial rights included, so you can use the extended tracks in apps, games, videos, podcasts, and client work.