Connecting Your Max for Live Device to a Cloud API

Introduction

In our previous article, we built a Max for Live device that exports arrangement locators to JSON. The data stayed local — displayed in the device UI or saved to a file.

Now let's take it further: sending that data to a cloud API where it can be stored, visualized, and integrated with other tools.

Ableton Live with Max for Live device sending data to Cloud API

Why Connect to an API?

Local JSON files are useful, but they have limitations:

Local Files	Cloud API
Manual file management	Automatic storage
Single machine access	Access from anywhere
No version history	Full export history
No visualization	Browser-based timeline view
Manual sharing	Team collaboration

By connecting your Max for Live device to an API, every export becomes part of a searchable, visualized database.

Architecture Overview (C4 Model)

We use the C4 model to document the system architecture. Here's the System Landscape showing all actors and systems:

C4 System Landscape - Music Producer, Ableton Live, and Export API

And the Container View showing internal components:

C4 Container View - Max for Live Device, Export API, Database

Key Components

Container	Technology	Responsibility
Max for Live Device	JavaScript, Node for Max	Extracts metadata from Ableton, sends to API
Export API	FastAPI, Cloud Run	Receives, validates, stores exports
Database	PostgreSQL (Cloud SQL)	Persistent storage with JSON sections

The API: Receiving Ableton Exports

Our API is built with FastAPI and deployed on Google Cloud Run. Here's the core endpoint:

POST /api/ableton/exports

Receives and stores project metadata from Ableton Live.

Request Schema:

{
  "project": "my_track",
  "bpm": 103.34,
  "time_signature": {
    "numerator": 4,
    "denominator": 4
  },
  "downbeat_seconds": 0,
  "sections": [
    { "label": "INTRO", "time_seconds": 0 },
    { "label": "VERSE", "time_seconds": 16 },
    { "label": "CHORUS", "time_seconds": 48 }
  ],
  "exported_at": "2026-01-27T14:30:00Z",
  "file_path": "/Users/producer/Music/my_track.als"
}

Response:

{
  "id": "550e8400-e29b-41d4-a716-446655440000",
  "project_name": "my_track",
  "bpm": 103.34,
  "time_signature": { "numerator": 4, "denominator": 4 },
  "downbeat_seconds": 0,
  "sections": [...],
  "exported_at": "2026-01-27T14:30:00Z",
  "created_at": "2026-01-27T14:30:05Z",
  "is_duplicate": false
}

Idempotency

The API is idempotent — if you accidentally export the same project twice with the same timestamp, it returns the existing record with is_duplicate: true instead of creating a duplicate.

Extending the Max for Live Device

Now let's modify our JavaScript to send data to the API.

The Challenge: Max for Live HTTP Requests

Max for Live's JavaScript environment doesn't have native fetch() or XMLHttpRequest. Instead, we use the jweb or maxurl objects, or — the simplest approach — shell out to curl.

Core Logic (marker_export.js)

The JavaScript extends our previous export script with API communication:

// Pseudo-code: marker_export.js

function bang() {
  // 1. Get project data from Live via LiveAPI
  song = new LiveAPI("live_set")

  name = song.get("name")           // Project name
  bpm = song.get("tempo")           // BPM
  sigNum = song.get("signature_numerator")
  sigDen = song.get("signature_denominator")

  // 2. Collect all locators (cue points)
  locatorIds = song.get("cue_points")
  sections = []

  for each locatorId:
    locator = new LiveAPI("id " + locatorId)
    sections.push({
      label: locator.get("name"),      // "INTRO", "VERSE", etc.
      time_seconds: locator.get("time") // Position in seconds
    })

  // 3. Build payload matching API schema
  payload = {
    project: name,
    bpm: bpm,
    time_signature: { numerator: sigNum, denominator: sigDen },
    sections: sections,
    exported_at: now()
  }

  // 4. Display in UI + send to API
  outlet(0, JSON.stringify(payload))  // → textedit (preview)
  outlet(1, payload)                   // → node.script (API sender)
}

Key insight: LiveAPI returns arrays for most properties, so always handle Array.isArray() checks.

Alternative: Using node.script

For a more robust solution, use the node.script object which runs a Node.js script directly within Max:

Max for Live patcher with node.script for API communication

The patcher architecture:

┌─────────────────┐     ┌──────────────────────┐     ┌────────────────┐
│   textbutton    │────▶│  js marker_export.js │────▶│   textedit     │
│    "Export"     │     │                      │     │  (JSON output) │
└─────────────────┘     └──────────┬───────────┘     └────────────────┘
                                   │
                                   ▼
                        ┌──────────────────────────────────────┐
                        │  node.script api_sender.js           │
                        │  @autostart 1 @outlets 1             │
                        └──────────────────┬───────────────────┘
                                           │
                                           ▼
                                 ┌────────────────┐
                                 │   textedit     │
                                 │ (API status)   │
                                 └────────────────┘

The node.script object runs a Node.js script within Max, providing full access to npm packages and modern JavaScript features.

The API Sender (api_sender.js)

The node.script object runs a Node.js script that handles HTTP communication:

// Pseudo-code: api_sender.js

const Max = require('max-api');
const API_URL = "https://your-api.run.app/api/ableton/exports";

Max.addHandler("export", async (jsonString) => {
  // 1. Parse incoming data from marker_export.js
  const payload = JSON.parse(jsonString);

  // 2. POST to API
  const response = await fetch(API_URL, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify(payload)
  });

  // 3. Handle response
  const result = await response.json();

  if (result.is_duplicate) {
    Max.outlet("status", "Already exported");
  } else {
    Max.outlet("status", "Saved: " + result.id);
  }
});

Why node.script? Unlike Max's built-in JS, node.script provides full Node.js runtime with npm packages, async/await, and modern fetch API.

The API Implementation

The backend is a FastAPI service with PostgreSQL storage:

# Pseudo-code: FastAPI endpoint

@router.post("/ableton/exports")
async def create_export(data: AbletonExportSchema, db: Session):

    # 1. Idempotency check — prevent duplicates
    existing = db.query(Export).filter(
        project == data.project,
        exported_at == data.exported_at
    ).first()

    if existing:
        return { ...existing, is_duplicate: True }

    # 2. Store new export
    export = Export(
        id = uuid4(),
        project_name = data.project,
        bpm = data.bpm,
        sections = data.sections,    # JSON array
        exported_at = data.exported_at
    )

    db.add(export)
    db.commit()

    return { ...export, is_duplicate: False }

Key design decisions:

Idempotency via unique constraint on (project_name, exported_at)
Sections stored as JSON for flexibility
UUID primary keys for distributed systems compatibility

Browser UI: Visualizing Your Exports

The API includes a browser-based UI at /browser that shows all your exports:

Browser UI with timeline visualization of Ableton exports

Features

Feature	Description
Timeline visualization	Ableton-style arrangement view
Filters	By project, BPM range, section count
Search	Find exports by name
Pagination	Handle large export histories
JSON inspection	Click to see full export data

Timeline Rendering

Each export is visualized as a horizontal timeline with color-coded sections:

Timeline visualization with color-coded sections

The visualization is generated client-side using vanilla JavaScript and CSS Grid, making it lightweight and fast.

Additional API Endpoints

GET /api/ableton/exports

List all exports with pagination and filtering:

curl "https://api.example.com/api/ableton/exports?project=my_track&page=1&limit=20"

GET /api/ableton/exports/{id}

Get a specific export by ID:

curl "https://api.example.com/api/ableton/exports/550e8400-e29b-41d4-a716-446655440000"

GET /api/ableton/projects

Get list of all unique project names:

curl "https://api.example.com/api/ableton/projects"

Response:

{
  "projects": ["my_track", "remix_v2", "collab_final"]
}

Deployment

The API runs on Google Cloud Run with Cloud SQL (PostgreSQL):

Component	Service
API	Cloud Run (serverless containers)
Database	Cloud SQL PostgreSQL
Region	europe-west1

Local development uses Docker Compose with the same PostgreSQL setup, ensuring dev/prod parity.

Testing the Integration

From Ableton

Open a project with arrangement locators
Add the Max for Live device to any MIDI track
Click "Export"
Watch the status panel — should show "Saved: uuid"
Open Browser UI — your export appears in the timeline

Verify with curl

curl "https://your-api.run.app/api/ableton/projects"
# Returns: { "projects": ["your_project_name", ...] }

Security Considerations

For a production deployment, consider:

Concern	Solution
Authentication	Add API keys or OAuth
Rate limiting	Prevent abuse
CORS	Restrict allowed origins
Input validation	Already handled by Pydantic
HTTPS	Enforced by Cloud Run

What's Next?

This pipeline enables several advanced workflows:

AI comparison — Compare manual annotations with AI-detected structures
Cross-DAW sync — Export from Ableton, import to REAPER/Logic
Version tracking — See how your arrangement evolved over time
Team collaboration — Share structure data with collaborators
Automated processing — Trigger downstream tasks on new exports

Exporting Ableton Live Locators to JSON with Max for Live — Build the Max for Live device
Automatic Song Structure Analysis – How AI Detects Intro, Verse, and Chorus — AI-powered structure detection

By connecting your Max for Live device to a cloud API, you transform Ableton from an isolated creative tool into a node in a larger data pipeline. Every arrangement decision, every locator you place, becomes structured data that can power visualizations, training datasets, and cross-platform workflows.

The key insight: your DAW is a data source. Treating it that way opens up possibilities that weren't available when everything stayed local.

At Music Tech Lab, we build bridges between music production and software engineering. Have questions about DAW-API integration or want to discuss architecture? Get in touch.