Add Vocals APISing Lyrics Over Instrumentals
Turn an instrumental into a full song with one REST call. Pass a source clip and your lyrics, render sung vocals over the track, poll for the result, and download — with API keys, free trial credits, pricing, webhooks, and production-ready docs.
What is the Add Vocals API?
Add vocals takes an existing instrumental clip and sings your lyrics over it. It runs through the generation endpoint with a task_type of add_vocals, so it shares the same auth, polling, and download flow as the rest of the API — just point it at a clip and pass the words.
- Vocals on Demand
Pass a
continue_clip_idfor the instrumental and the lyrics in the prompt — the API sings them over the track.- Placement Control
Optionally set
overpainting_start_sto influence where the vocals begin.- Latest Models
Runs on sonic-v4-5-plus, sonic-v5, or sonic-v5-5 for high-fidelity vocal rendering.
API Examples
Add vocals to an instrumental, then poll the task until it's ready.
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": "add_vocals",
6 "continue_clip_id": "YOUR_INSTRUMENTAL_CLIP_ID",
7 "prompt": "[Verse]\nCity lights and open roads...",
8 "mv": "sonic-v5"
9}'mv must be one of sonic-v4-5-plus, sonic-v5, or sonic-v5-5. Need lyrics first? Generate them with the AI Lyrics API.
Why Build Vocals on MusicAPI?
Instrumental → Song
Turn any backing track into a vocal song.
Async + Fast
Returns a task id instantly; tracks finish in 1-3 min.
Auto-Refunds
Failed upstream tasks are refunded; polling is free.
Pairs with Lyrics
Generate lyrics, then sing them in one flow.
Add Vocals API: Pricing, Free Access & API Keys
Developers adding vocals to instrumentals 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 add-vocals, polling, and downloads before choosing a paid plan.
Pricing
Credit-based, same as generation. Estimate per-call cost on the pricing page.
API keys
Generate a bearer token in your account, keep it server-side, and call the add-vocals endpoint.
Ready to Add AI Vocals?
Turn instrumentals into full songs with a single endpoint. Start free, then scale with predictable credit pricing.
Frequently Asked Questions
Everything you need to know about adding vocals with the API.
What is an add vocals API?
An add vocals API renders sung vocals over an existing instrumental clip. With MusicAPI you call /api/v1/sonic/create with task_type 'add_vocals', the source clip id, and the lyrics you want sung.
How do I add vocals to an instrumental with the API?
POST to https://api.musicapi.ai/api/v1/sonic/create with task_type 'add_vocals', a continue_clip_id (the instrumental), the prompt (your lyrics), and a supported model version. The call returns a task_id; poll GET /api/v1/sonic/task/{id} until the vocal track is ready, then download.
Which model versions support add vocals?
Add vocals requires a recent model: mv must be one of sonic-v4-5-plus, sonic-v5, or sonic-v5-5. Older versions are not supported for this task type.
Do I provide the lyrics?
Yes — pass the lyrics in the prompt field. If you don't have lyrics yet, generate them first with the AI lyrics endpoint and feed the result straight into the add_vocals call.
Can I control where the vocals start?
You can optionally pass overpainting_start_s (a number, in seconds) to influence where vocals begin over the instrumental. Omit it to use the default behavior.
Is add vocals synchronous or asynchronous?
Asynchronous. The create call returns a task_id immediately and the vocal track is produced in the background, typically within 1-3 minutes. Use polling on the task endpoint or webhooks to detect completion.
Do the results include commercial rights?
Yes, audio generated through the API comes with commercial rights included. You own the generated content and can use it for commercial purposes.