Replace Section

curl --request POST \
  --url https://api.apimart.ai/v1/music/generations/replaceFlowMusic \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '{
    "model": "flowmusic",
    "clip_id": "abc123-def456",
    "start_s": 10,
    "end_s": 20,
    "instruction": "Replace with a piano version"
  }'

import requests

url = "https://api.apimart.ai/v1/music/generations/replaceFlowMusic"

payload = {
    "model": "flowmusic",
    "clip_id": "abc123-def456",
    "start_s": 10,
    "end_s": 20,
    "instruction": "Replace with a piano version"
}

headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.json())

const url = "https://api.apimart.ai/v1/music/generations/replaceFlowMusic";

const payload = {
  model: "flowmusic",
  clip_id: "abc123-def456",
  start_s: 10,
  end_s: 20,
  instruction: "Replace with a piano version"
};

const headers = {
  "Authorization": "Bearer <token>",
  "Content-Type": "application/json"
};

fetch(url, {
  method: "POST",
  headers: headers,
  body: JSON.stringify(payload)
})
  .then(response => response.json())
  .then(data => console.log(data))
  .catch(error => console.error('Error:', error));

{
  "code": 200,
  "data": [
    {
      "status": "submitted",
      "task_id": "task_01KWXVHGTG5JM33S8FG1K90YQ6"
    }
  ]
}

{
  "error": {
    "message": "end_s must be greater than start_s",
    "type": "invalid_request",
    "param": "",
    "code": "invalid_request"
  }
}

{
  "error": {
    "message": "Insufficient balance",
    "type": "invalid_request",
    "param": "",
    "code": "quota_not_enough"
  }
}

{
  "error": {
    "message": "Current group capacity is saturated, please retry later",
    "type": "rate_limit_error",
    "param": "",
    "code": "rate_limit_error"
  }
}

POST

music

generations

replaceFlowMusic

curl --request POST \
  --url https://api.apimart.ai/v1/music/generations/replaceFlowMusic \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '{
    "model": "flowmusic",
    "clip_id": "abc123-def456",
    "start_s": 10,
    "end_s": 20,
    "instruction": "Replace with a piano version"
  }'

import requests

url = "https://api.apimart.ai/v1/music/generations/replaceFlowMusic"

payload = {
    "model": "flowmusic",
    "clip_id": "abc123-def456",
    "start_s": 10,
    "end_s": 20,
    "instruction": "Replace with a piano version"
}

headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.json())

const url = "https://api.apimart.ai/v1/music/generations/replaceFlowMusic";

const payload = {
  model: "flowmusic",
  clip_id: "abc123-def456",
  start_s: 10,
  end_s: 20,
  instruction: "Replace with a piano version"
};

const headers = {
  "Authorization": "Bearer <token>",
  "Content-Type": "application/json"
};

fetch(url, {
  method: "POST",
  headers: headers,
  body: JSON.stringify(payload)
})
  .then(response => response.json())
  .then(data => console.log(data))
  .catch(error => console.error('Error:', error));

{
  "code": 200,
  "data": [
    {
      "status": "submitted",
      "task_id": "task_01KWXVHGTG5JM33S8FG1K90YQ6"
    }
  ]
}

{
  "error": {
    "message": "end_s must be greater than start_s",
    "type": "invalid_request",
    "param": "",
    "code": "invalid_request"
  }
}

{
  "error": {
    "message": "Insufficient balance",
    "type": "invalid_request",
    "param": "",
    "code": "quota_not_enough"
  }
}

{
  "error": {
    "message": "Current group capacity is saturated, please retry later",
    "type": "rate_limit_error",
    "param": "",
    "code": "rate_limit_error"
  }
}

curl --request POST \
  --url https://api.apimart.ai/v1/music/generations/replaceFlowMusic \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '{
    "model": "flowmusic",
    "clip_id": "abc123-def456",
    "start_s": 10,
    "end_s": 20,
    "instruction": "Replace with a piano version"
  }'

import requests

url = "https://api.apimart.ai/v1/music/generations/replaceFlowMusic"

payload = {
    "model": "flowmusic",
    "clip_id": "abc123-def456",
    "start_s": 10,
    "end_s": 20,
    "instruction": "Replace with a piano version"
}

headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.json())

const url = "https://api.apimart.ai/v1/music/generations/replaceFlowMusic";

const payload = {
  model: "flowmusic",
  clip_id: "abc123-def456",
  start_s: 10,
  end_s: 20,
  instruction: "Replace with a piano version"
};

const headers = {
  "Authorization": "Bearer <token>",
  "Content-Type": "application/json"
};

fetch(url, {
  method: "POST",
  headers: headers,
  body: JSON.stringify(payload)
})
  .then(response => response.json())
  .then(data => console.log(data))
  .catch(error => console.error('Error:', error));

{
  "code": 200,
  "data": [
    {
      "status": "submitted",
      "task_id": "task_01KWXVHGTG5JM33S8FG1K90YQ6"
    }
  ]
}

{
  "error": {
    "message": "end_s must be greater than start_s",
    "type": "invalid_request",
    "param": "",
    "code": "invalid_request"
  }
}

{
  "error": {
    "message": "Insufficient balance",
    "type": "invalid_request",
    "param": "",
    "code": "quota_not_enough"
  }
}

{
  "error": {
    "message": "Current group capacity is saturated, please retry later",
    "type": "rate_limit_error",
    "param": "",
    "code": "rate_limit_error"
  }
}

Authentication

string

required

All endpoints require Bearer Token authenticationGet your API Key:Visit the API Key management page to get your API KeyAdd it to the request header:

Authorization: Bearer YOUR_API_KEY

Request Parameters

string

required

Model name, must be "flowmusic" (case-insensitive)

string

required

Source music clip_id, from a successful task’s result.music[].clip_id

number

required

Replacement start time (seconds)

number

required

Replacement end time (seconds)

end_s must be greater than start_s and cannot exceed the source clip’s duration.

string

required

Editing instruction for the replaced sectionExample: "Replace with a piano version"

string

Title of the music after replacement

integer

Random seed, used to reproduce or control the generation result

Response

integer

Response status code, 200 on success

array

Array of returned data

Show Array elements

string

Task status, submitted upon initial submission

string

Unique task identifier, used to query task status and results

Use Cases

Scenario 1: Replace seconds 10-20 with a piano version

{
  "model": "flowmusic",
  "clip_id": "abc123-def456",
  "start_s": 10,
  "end_s": 20,
  "instruction": "Replace with a piano version"
}

Query Task ResultsSection replacement is an asynchronous task; a task_id is returned after submission. Use the Get Task Status endpoint to query generation progress and results. The replacement output is a new clip_id (the whole song is re-rendered with the specified segment replaced); use the new clip_id for subsequent operations.

Completed Task Result Example

Query response example (GET /v1/music/tasks/{task_id}):

{
  "code": 200,
  "data": {
    "id": "task_01KWXVHGTG5JM33S8FG1K90YQ6",
    "status": "completed",
    "progress": 100,
    "created": 1783413392,
    "completed": 1783413454,
    "actual_time": 62,
    "cost": 0.048,
    "credits_cost": 0.48,
    "result": {
      "music": [
        {
          "clip_id": "9508d1fe-633e-464b-8a40-c6368e5464fa",
          "title": "Untitled (Replaced)",
          "duration_seconds": "181.58933333",
          "create_time": "2026-07-07T08:37:13.864452Z",
          "lyrics": "[Verse 1]\nWaking up to the morning light,\n...",
          "lyrics_id": "c302d603-81b6-552f-8122-e512928d6aa1",
          "lyrics_timing_markers": [[10, 12], [71, 15]],
          "audio_url": "https://cdn.apimart.ai/audio/flowmusic_9508d1fe.m4a",
          "wav_url": "https://cdn.apimart.ai/audio/flowmusic_9508d1fe.wav",
          "image_url": "https://cdn.apimart.ai/image/flowmusic_9508d1fe_cover.jpg"
        }
      ]
    }
  }
}

Extend Music Cover Rearrangement

Overview

Text Series

Image Series

Video Series

Audio Series

Moderation Series

Upload Management

Task Management

Account Management

Replace Section

Authentication

Request Parameters

Response

Use Cases

Scenario 1: Replace seconds 10-20 with a piano version

Completed Task Result Example

​Authentication

​Request Parameters

​Response

​Use Cases

​Scenario 1: Replace seconds 10-20 with a piano version

​Completed Task Result Example

Authentication

Request Parameters

Response

Use Cases

Scenario 1: Replace seconds 10-20 with a piano version

Completed Task Result Example