A JavaScript SDK for AI model inference with integrated billing, rate limiting, and user management. Subscribe.dev provides access to curated AI models with built-in cost tracking and analytics through a unified API.

Features

🚀 100+ AI Models - Curated collection of state-of-the-art models for various use cases
💰 Integrated Billing - Transparent pricing with automatic cost tracking and detailed usage analytics
🔒 Secure Authentication - Dual-layer authentication with project and user-level access control
⚡ Rate Limiting - Built-in request queuing with configurable limits and retry logic
📊 Usage Analytics - Real-time tracking of requests, costs, and performance metrics
🔐 User Storage - Session data persistence and user preferences management
📱 JavaScript Support - Works in Node.js, browser, and JavaScript runtime environments
🛡️ Error Handling - Comprehensive error types with detailed context and retry mechanisms
🎯 Easy Integration - Compatible with existing JavaScript AI workflows

Getting Started

1. Create a Subscribe.dev Account

Visit Subscribe.dev and create an account
Create a new project in your dashboard
Copy your project API key (starts with pub_) from the project overview
Leave defaults-- or configure your users' plans, features and limits

2. Installation

npm install @subscribe.dev/client
# or
yarn add @subscribe.dev/client
# or
bun add @subscribe.dev/client

3. Quick Start

import { SubscribeDevClient } from '@subscribe.dev/client'

// Initialize the client with your [Subscribe.dev](https://subscribe.dev) credentials
const client = new SubscribeDevClient({
  apiKey: 'pub_your_project_api_key', // From your [Subscribe.dev](https://subscribe.dev) project dashboard
  userKey: 'your_user_token'          // From your [Subscribe.dev](https://subscribe.dev) account
})

// Run any AI model with a single API call
const result = await client.run('black-forest-labs/flux-schnell', {
  input: {
    prompt: 'A majestic mountain landscape at sunset',
    num_inference_steps: 4,
    guidance_scale: 3.5
  }
})

console.log('Generated image:', result.output)

Configuration

SubscribeDevClientConfig

interface SubscribeDevClientConfig {
  /** Public API key (project bearer token) - required */
  apiKey: string
  
  /** User token for user-specific limits and features */
  userKey: string
  
  
  /** Request timeout in milliseconds (default: 300000 = 5 minutes) */
  timeout?: number
  
  /** Maximum retry attempts (default: 2) */
  maxRetries?: number
  
  /** Enable debug logging (default: false) */
  debug?: boolean
}

API Reference

Core Methods

`run(model, options)`

The main method for running predictions. Returns completed results.

await client.run(
  'black-forest-labs/flux-schnell',
  {
    input: {
      prompt: 'A beautiful landscape',
      width: 1024,
      height: 1024
    },
    webhook?: 'https://your-site.com/webhook',
    webhook_events_filter?: ['completed', 'failed']
  }
)

Returns: Promise<Prediction> - Completed prediction with output

`createPrediction(model, options)`

Create a prediction and return immediately (legacy method).

const prediction = await client.createPrediction('model-name', {
  input: { prompt: 'test' }
})

Balance & Billing

`getBalance()`

Get current project and user credit balances.

const balance = await client.getBalance()
console.log('Project credits:', balance.project.remainingCredits)
console.log('User credits:', balance.user?.remainingCredits)

Returns: Promise<BalanceInfo>

interface BalanceInfo {
  project: ProjectBalance
  user?: UserBalance
}

interface ProjectBalance {
  projectId: string
  totalCredits: number
  usedCredits: number
  remainingCredits: number
  lastUpdated: Date
}

`getTransactions(options?)`

Retrieve transaction history with filtering.

const history = await client.getTransactions({
  limit: 50,
  offset: 0,
  status: 'completed',
  model: 'black-forest-labs/flux-schnell',
  startDate: '2024-01-01',
  endDate: '2024-12-31'
})

Returns: Promise<TransactionHistory>

Rate Limiting

`getRateLimits()`

Get current rate limit status.

const limits = await client.getRateLimits()
console.log('Concurrent requests:', limits.concurrent.currentRequests)
console.log('Hourly limit reached:', !limits.hour?.allowed)

User Storage

`getStorage(options?)`

Retrieve user session data.

const storage = await client.getStorage({ appVersion: 'v1.0' })
console.log('Session data:', storage.sessionData)

`setStorage(sessionData, options?)`

Update user session data.

await client.setStorage(
  { preferences: { theme: 'dark' }, gameState: { level: 5 } },
  { appVersion: 'v1.0' }
)

`deleteStorage(options?)`

Clear user session data.

await client.deleteStorage({ appVersion: 'v1.0' })

Browser Convenience Methods

`persistSessionData(options?)`

Sync session data to localStorage (browser only).

// Automatically saves to localStorage and server
const storage = await client.persistSessionData()

`getSessionData(options?)`

Get session data with localStorage caching.

// Always fetches from server, updates localStorage cache
const sessionData = await client.getSessionData()

Subscription Management

`getSubscriptionStatus()`

Get user subscription information (requires userKey).

// Requires userKey in client configuration
const subscription = await client.getSubscriptionStatus()

if (subscription.hasActiveSubscription) {
  console.log('Plan:', subscription.plan?.name)
  console.log('Credits:', subscription.plan?.tokenLimit)
}

Authentication

Subscribe.dev uses a dual authentication system:

Project API Keys

Format: pub_[base64_jwt_token]
Scope: Project-level access and billing
Location: Get from Subscribe.dev dashboard → Project → Overview tab
Usage: Required for all requests

const client = new SubscribeDevClient({
  apiKey: 'pub_eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...'
})

User Tokens (Required)

Scope: User-specific limits and storage
Usage: Per-user rate limiting and session management

const client = new SubscribeDevClient({
  apiKey: 'pub_your_project_key',
  userKey: 'user_specific_token'
})

Error Handling

The client provides specific error types for different scenarios:

import { 
  SubscribeDevClient, 
  InsufficientBalanceError, 
  RateLimitError,
  AuthenticationError,
  ValidationError
} from '@subscribe.dev/client'

try {
  const result = await client.run('model-name', { input: {} })
} catch (error) {
  if (error instanceof InsufficientBalanceError) {
    console.log('Remaining credits:', error.details?.remainingCredits)
    console.log('Required credits:', error.details?.requiredCredits)
    console.log('Pricing page:', client.pricingUrl)
  } else if (error instanceof RateLimitError) {
    console.log('Rate limited until:', error.resetTime)
    console.log('Retry after seconds:', error.retryAfter)
  } else if (error instanceof AuthenticationError) {
    console.log('Invalid API key or user token')
  } else if (error instanceof ValidationError) {
    console.log('Invalid request:', error.details)
  }
}

Error Types

SubscribeDevError - Base error class
InsufficientBalanceError - Not enough credits (402)
RateLimitError - Rate limit exceeded (429)
AuthenticationError - Invalid credentials (401)
AccessDeniedError - Permission denied (403)
NotFoundError - Resource not found (404)
ValidationError - Invalid request data (400)

Usage Examples

Basic Image Generation

import { SubscribeDevClient } from '@subscribe.dev/client'

const client = new SubscribeDevClient({
  apiKey: process.env.SUBSCRIBE_DEV_API_KEY!
})

const result = await client.run('black-forest-labs/flux-schnell', {
  input: {
    prompt: 'A cyberpunk cityscape at night, neon lights, 4k',
    num_inference_steps: 4,
    guidance_scale: 3.5,
    width: 1024,
    height: 1024
  }
})

console.log('Generated images:', result.output) // Array of image URLs

With User Token and Error Handling

import { SubscribeDevClient, InsufficientBalanceError } from '@subscribe.dev/client'

const client = new SubscribeDevClient({
  apiKey: process.env.SUBSCRIBE_DEV_API_KEY!,
  userKey: process.env.USER_TOKEN!, // User-specific limits
  debug: true
})

try {
  // Check balance first
  const balance = await client.getBalance()
  console.log('Available credits:', balance.project.remainingCredits)

  if (balance.project.remainingCredits < 10) {
    console.log('Low credits! Consider upgrading:', client.pricingUrl)
  }

  // Run prediction
  const result = await client.run('stability-ai/sdxl', {
    input: {
      prompt: 'A majestic dragon in a fantasy landscape'
    }
  })

  console.log('Success!', result.output)

  // Check updated balance
  const newBalance = await client.getBalance()
  const used = balance.project.remainingCredits - newBalance.project.remainingCredits
  console.log('Credits used:', used)

} catch (error) {
  if (error instanceof InsufficientBalanceError) {
    console.error('Need more credits:', error.details)
  } else {
    console.error('Error:', error.message)
  }
}

Session Storage Example

const client = new SubscribeDevClient({
  apiKey: process.env.SUBSCRIBE_DEV_API_KEY!,
  userKey: process.env.USER_TOKEN! // Required for storage
})

// Load existing session data
const existingData = await client.getSessionData()
console.log('Previous session:', existingData)

// Update session with new data
await client.setStorage({
  ...existingData,
  lastModel: 'black-forest-labs/flux-schnell',
  generationCount: (existingData.generationCount || 0) + 1,
  preferences: {
    defaultSteps: 4,
    favoriteStyles: ['photorealistic', 'cinematic']
  }
})

// In browser environments, also sync to localStorage
if (typeof window !== 'undefined') {
  await client.persistSessionData()
}

Transaction History and Analytics

// Get recent completed transactions
const history = await client.getTransactions({
  limit: 20,
  status: 'completed'
})

console.log(`Found ${history.transactions.length} transactions`)

// Calculate total spending
const totalCost = history.transactions.reduce(
  (sum, tx) => sum + (tx.actualCost || tx.estimatedCost), 
  0
)
console.log('Total spent:', totalCost, 'credits')

// Find most used models
const modelUsage = history.transactions.reduce((acc, tx) => {
  acc[tx.modelName] = (acc[tx.modelName] || 0) + 1
  return acc
}, {} as Record<string, number>)

console.log('Model usage:', modelUsage)

Rate Limit Monitoring

// Check current rate limits
const limits = await client.getRateLimits()

console.log('Rate limit status:')
console.log(`Concurrent: ${limits.concurrent.currentRequests}/${limits.concurrent.maxRequests}`)

if (limits.minute) {
  console.log(`Per minute: ${limits.minute.currentRequests}/${limits.minute.maxRequests}`)
  console.log(`Resets at: ${limits.minute.resetTime}`)
}

if (limits.hour) {
  console.log(`Per hour: ${limits.hour.currentRequests}/${limits.hour.maxRequests}`)
}

// Check if we're approaching limits
if (limits.concurrent.currentRequests > limits.concurrent.maxRequests * 0.8) {
  console.warn('Approaching concurrent request limit')
}

Environment Variables

# Required - Your Subscribe.dev project API key
SUBSCRIBE_DEV_API_KEY=pub_your_api_key_here

# Required - User token for user-specific features
SUBSCRIBE_DEV_USER_KEY=your_user_token_here

TypeScript Support

The client is written in TypeScript and provides full type definitions:

import type { 
  SubscribeDevClientConfig,
  Prediction,
  BalanceInfo,
  TransactionHistory,
  UserStorage,
  SubscriptionStatus
} from '@subscribe.dev/client'

Migration from Other Platforms

The Subscribe.dev client offers seamless migration:

// Before (Other platforms)
import OtherClient from 'other-ai-platform'
const client = new OtherClient({ auth: 'your-token' })

// After (Subscribe.dev - More models, better features)
import { SubscribeDevClient } from '@subscribe.dev/client'
const client = new SubscribeDevClient({ apiKey: 'pub_your-token' })

// Same API
const result = await client.run('model-name', { input: {} })

Key Advantages

Unified Access: Single SDK for 100+ curated models across multiple AI providers
Built-in Management: Native billing, analytics, and user management for production applications
Optimized Requests: Intelligent routing with automatic retries and completion handling
Extended Features: User storage, subscription management, and detailed analytics
Transparent Pricing: Clear cost tracking with automatic optimization
Reliable Operation: Comprehensive error handling and monitoring capabilities

Browser Usage

The client works in browser environments with CORS support:

<script type="module">
import { SubscribeDevClient } from 'https://unpkg.com/@subscribe.dev/client@latest/dist/index.js'

const client = new SubscribeDevClient({
  apiKey: 'pub_your_public_api_key', // Safe to embed in frontend
  userKey: localStorage.getItem('user_token')! // User context
})

// Use normally
const result = await client.run('model', { input: {} })
</script>

Contributing

Fork the repository
Create a feature branch
Make your changes
Add tests
Submit a pull request

Support

📖 Documentation: docs.subscribe.dev
🐛 Issues: GitHub Issues
💬 Discord: Join our community
📧 Email: support@subscribe.dev

License

MIT License - see LICENSE for details.

Keywords

FAQs

Package last updated on 05 Sep 2025

Did you know?

Socket for GitHub automatically highlights issues in each pull request and monitors the health of all your open source dependencies. Discover the contents of your packages and block harmful activity before you install or update your dependencies.

Install

@subscribe.dev/client