> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/upstash/context7/llms.txt
> Use this file to discover all available pages before exploring further.

# Context7 Client

> Initialize and configure the Context7 client for your application

## Constructor

Create a new Context7 client instance:

```typescript theme={null}
import { Context7 } from '@upstash/context7-sdk';

const client = new Context7(config);
```

### Parameters

<ParamField path="config" type="Context7Config" default="{}">
  Configuration object for the client

  <Expandable title="properties">
    <ParamField path="apiKey" type="string" optional>
      Your Context7 API key. If not provided, the client will look for the `CONTEXT7_API_KEY` environment variable.
    </ParamField>
  </Expandable>
</ParamField>

### Returns

A configured `Context7` client instance.

### Throws

* `Context7Error`: If no API key is provided and `CONTEXT7_API_KEY` environment variable is not set

## Configuration Options

### Using Environment Variables

The recommended approach for production applications:

```typescript theme={null}
// Set environment variable
process.env.CONTEXT7_API_KEY = 'ctx7sk-your-api-key';

// Initialize without config
const client = new Context7();
```

### Using Direct Configuration

Useful for testing or when you need multiple clients:

```typescript theme={null}
const client = new Context7({
  apiKey: 'ctx7sk-your-api-key'
});
```

### Priority Order

When both methods are used, the constructor parameter takes precedence:

```typescript theme={null}
process.env.CONTEXT7_API_KEY = 'ctx7sk-env-key';

const client = new Context7({
  apiKey: 'ctx7sk-config-key' // This one will be used
});
```

## Built-in Features

The client automatically configures several features:

### Automatic Retries

Failed requests are retried up to 5 times with exponential backoff:

* Retry 1: \~50ms delay
* Retry 2: \~135ms delay
* Retry 3: \~403ms delay
* Retry 4: \~1.1s delay
* Retry 5: \~3s delay

### Authentication

API key is automatically included in all requests as a Bearer token in the Authorization header.

### Cache Control

Requests are configured with `cache: "no-store"` to ensure fresh results.

## Error Handling

### Missing API Key

```typescript theme={null}
try {
  const client = new Context7(); // No API key provided
} catch (error) {
  if (error instanceof Context7Error) {
    console.error(error.message);
    // "API key is required. Pass it in the config or set CONTEXT7_API_KEY environment variable."
  }
}
```

### Invalid API Key Format

If your API key doesn't start with `ctx7sk`, you'll see a warning:

```typescript theme={null}
const client = new Context7({ apiKey: 'invalid-key' });
// Console warning: "API key should start with 'ctx7sk'"
```

## Usage Examples

### Basic Setup

```typescript theme={null}
import { Context7 } from '@upstash/context7-sdk';

const client = new Context7({
  apiKey: process.env.CONTEXT7_API_KEY
});

// Client is ready to use
const libraries = await client.searchLibrary('query', 'react');
```

### Multiple Clients

Create separate clients for different API keys or use cases:

```typescript theme={null}
const productionClient = new Context7({
  apiKey: process.env.CONTEXT7_PRODUCTION_KEY
});

const testClient = new Context7({
  apiKey: process.env.CONTEXT7_TEST_KEY
});
```

### Singleton Pattern

Reuse a single client instance across your application:

```typescript theme={null}
// lib/context7.ts
import { Context7 } from '@upstash/context7-sdk';

export const context7Client = new Context7({
  apiKey: process.env.CONTEXT7_API_KEY
});
```

```typescript theme={null}
// app/api/search/route.ts
import { context7Client } from '@/lib/context7';

export async function GET(request: Request) {
  const libraries = await context7Client.searchLibrary('query', 'react');
  return Response.json(libraries);
}
```

### Edge Runtime (Next.js, Cloudflare Workers)

The SDK works in edge runtimes:

```typescript theme={null}
// app/api/docs/route.ts
import { Context7 } from '@upstash/context7-sdk';

export const runtime = 'edge';

export async function GET(request: Request) {
  const client = new Context7({
    apiKey: process.env.CONTEXT7_API_KEY
  });
  
  const docs = await client.getContext('hooks', '/facebook/react');
  return Response.json(docs);
}
```

## Type Definitions

### Context7Config

```typescript theme={null}
interface Context7Config {
  apiKey?: string;
}
```

### Context7Error

```typescript theme={null}
class Context7Error extends Error {
  name: 'Context7Error';
  message: string;
}
```

## Available Methods

Once initialized, the client provides two main methods:

<CardGroup cols={2}>
  <Card title="searchLibrary" icon="magnifying-glass" href="/sdk/search-library">
    Search for libraries by name and query
  </Card>

  <Card title="getContext" icon="book" href="/sdk/get-context">
    Retrieve documentation snippets for a library
  </Card>
</CardGroup>