> ## Documentation Index
> Fetch the complete documentation index at: https://beta-docs.nevermind.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Development Guides

> Practical guides for building different types of AI applications with Nevermined.

Welcome to the development guide section. Here you'll find practical, step-by-step tutorials for building different types of monetized AI services using Nevermined.

These guides are designed to take you from concept to a functional, monetized application, covering common use cases and integration patterns.

## Prerequisites

Before starting, ensure you have:

<Steps>
  <Step title="Nevermined API Key">
    Get your API key from the [Nevermined App](https://app.nevermined.io)
  </Step>

  <Step title="Development Environment">
    * Node.js 16+ and npm/yarn
    * Python 3.8+ (for Python examples)
    * A code editor (VS Code recommended)
  </Step>

  <Step title="Blockchain Wallet">
    * MetaMask or compatible wallet
    * Some test tokens for the testing environment
  </Step>
</Steps>

## SDK Installation

<Tabs>
  <Tab title="TypeScript/JavaScript">
    ```bash theme={null}
    npm install @nevermined-io/payments
    # or
    yarn add @nevermined-io/payments
    ```
  </Tab>

  <Tab title="Python">
    ```bash theme={null}
    pip install payments-py
    ```
  </Tab>
</Tabs>

## Initialize the SDK

<Tabs>
  <Tab title="TypeScript">
    ```typescript theme={null}
    import { Payments } from '@nevermined-io/payments'

    const payments = Payments.getInstance({
      nvmApiKey: process.env.NVM_API_KEY,
      environment: 'testing' // or 'production'
    })
    ```
  </Tab>

  <Tab title="Python">
    ```python theme={null}
    from payments_py import Payments
    import os

    payments = Payments(
        api_key=os.environ.get('NVM_API_KEY'),
        environment='testing'  # or 'production'
    )
    ```
  </Tab>
</Tabs>

## Development Guides

<CardGroup>
  <Card title="Simple AI Agent Guide" icon="robot" href="/introduction/development/simple-ai-agent">
    Learn how to build and monetize a straightforward AI agent, like a chatbot or a simple API, from scratch.
  </Card>

  <Card title="Multi-Agent System Guide" icon="diagram-project" href="/introduction/development/multi-agent-system">
    Discover how to orchestrate a system where multiple AI agents collaborate and pay each other for services.
  </Card>
</CardGroup>

## Key Concepts for Development

### Agent Registration Flow

```mermaid theme={null}
sequenceDiagram
    participant Builder
    participant SDK
    participant Nevermined
    participant Blockchain
    
    Builder->>SDK: Register Agent & Plan
    SDK->>Nevermined: Submit Registration
    Nevermined->>Blockchain: Create Smart Contracts
    Blockchain-->>Nevermined: Confirmation
    Nevermined-->>SDK: Agent ID & Plan ID
    SDK-->>Builder: Registration Complete
```

### Subscriber Access Flow

```mermaid theme={null}
sequenceDiagram
    participant User
    participant SDK
    participant Nevermined
    participant Agent
    
    User->>SDK: Purchase Plan
    SDK->>Nevermined: Process Payment
    Nevermined-->>SDK: Access Token
    User->>Agent: Request with Token
    Agent->>Nevermined: Validate Token
    Nevermined-->>Agent: Validation Result
    Agent-->>User: Service Response
```

## Common Development Patterns

### 1. Direct Integration

Best for new services where you have full control:

* Integrate SDK directly into your application
* Handle validation in your code
* Maximum flexibility and control

### 2. Proxy Integration

Best for existing services:

* No code changes required
* Nevermined Proxy handles payments
* Quick to implement

### 3. Hybrid Approach

Combine both patterns:

* Use proxy for standard endpoints
* Direct integration for custom logic
* Balance between control and convenience

## Best Practices

<AccordionGroup>
  <Accordion icon="shield" title="Security">
    * Never expose your API key in client-side code
    * Use environment variables for sensitive data
    * Implement rate limiting
    * Validate all inputs
  </Accordion>

  <Accordion icon="gauge" title="Performance">
    * Cache access tokens
    * Batch API calls when possible
    * Monitor credit usage
    * Implement graceful error handling
  </Accordion>

  <Accordion icon="code" title="Code Organization">
    * Separate payment logic from business logic
    * Use middleware for authentication
    * Implement proper logging
    * Write tests for payment flows
  </Accordion>
</AccordionGroup>

## Choose Your Path

* If you are new to Nevermined or want to monetize a single AI service, start with the **Simple AI Agent Guide**.
* If you are building complex, autonomous systems where agents interact, head to the **Multi-Agent System Guide**.

Each guide provides code examples, architectural patterns, and best practices tailored to the specific use case.