ACE Step API
ACE Step is the most advanced open-source AI music model with 3.5 billion parameters, enabling users to generate high-quality music from text lyrics. We have retrained it for pop music and female vocals. In addition to providing an API, FoxAIHub also allows you to experience ACE Step directly on this page.
ACE Step music generator Free Online
Example Songs



ACE-Step API Document
Billing Rule
Each generate requestion returns 1 task id, and each task id can be used to query 1 song and 1 cover image. Each generate requestion costs $0.008.
How to use it ?
BaseUrl : https://api.foxaihub.com/api/v2
Headers Parameters
{"api-key": "Your API Key"}
You can find your api key on the dashboard.
Submit generation task
Path: /acestep/task
Method: POST
Content-Type: application/json
HTTP Body
{
"task_type": "generate",
"lyrics": "",
"tags": "pop, female vocals, drum & bass, piano",
"negative_prompt": "drum & bass",
"duration": 122,
"seed": 759249325
}
Parameter | Type | Required | Description |
---|---|---|---|
task_type | string | Yes | Generation task type, should be "generate" |
lyrics | string | Yes | The lyrics for the song to be generated |
tags | string | Yes | Music style tags, comma separated |
negative_prompt | string | No | Tags to be avoided in generation, but now it doesn't works, so you send an empty string |
duration | number | Yes | Duration of the song in seconds, from 0 to 240 seconds. If you set it to 0, it will be a random duration |
seed | number | No | Same seed will generate the same song. If you set it to 0, it will be a random seed |
How to generate a intrumental music?
You can set lyrics to [instrumental]
or [inst]
Response
{
"success": true,
"task_id": "0196ecef-1550-7000-b332-89ded5ca66db",
}
Get Results
Path: /acestep/task/{task_id}
Method: GET
Content-Type: application/json
Response
{
"status": "completed",
"task_id": "0196ebe0-4afd-7000-9a7b-67cf208209fd",
"gen_params": {
"seed": 0,
"tags": "pop, female vocals, drum & bass, piano",
"lyrics": "",
"duration": 120,
"task_type": "generate",
"negative_prompt": "drum & bass"
},
"data": {
"seed": 3842775294,
"end_time": "2025-05-20T04:08:06.852Z",
"audio_url": "https://cdn2.foxai.me/acestep-songs/0196ebe0-4afd-7000-9a7b-67cf208209fd.mp3",
"image_url": "https://cdn.foxai.me/image_c5a29c236cb96c2a9e9365690ceec649.jpeg"
},
"created_at": "2025-05-20T04:07:47.000Z"
}
ACE-Step Q&A

What is ACE Step ?
We present ACE-Step, a groundbreaking open-source model for music generation that addresses the limitations of existing methods and achieves top performance through comprehensive design. Current approaches struggle with balancing speed, coherence, and control. For example, LLM-based models like Yue and SongGen are good at aligning lyrics but are slow and produce structural artifacts. Conversely, diffusion models like DiffRhythm offer quicker synthesis but often fail to maintain long-range structural coherence.
What are the advantages of ACE Step ?
ACE Step has many advantages. First, it boasts fast generation capabilities. It only takes 10 seconds to generate 180 seconds of audio on an RTX 4090, which is particularly important for cost-sensitive users. Second, it has achieved the status of the top open-source AI music generation model. Among all relevant large models, ACE Step delivers the best performance. Most importantly, ACE Step has a vibrant open-source community and ecological expansion capabilities, allowing users to freely train LoRA models. We believe this is the "Stable Diffusion moment" in the AI music industry, and ACE Step represents the mainstream trend of future AI music. That's also why we released the ACE Step API as soon as possible.
How about our ACE Step api?
Thanks to our years of experience in the AI music API industry, we are proud to announce the launch of the Ace Step API. Our API is known for its stability, simplicity, and efficiency. Each song can be delivered in no more than 40 seconds. While native Ace Step integration typically requires tuning a large number of parameters, we've streamlined this process in advance, making it extremely easy to use the Ace Step API—just pass key parameters like lyrics and style.