context7

Documentation context retrieval using the Context7 API.

Prerequisites

Requires CONTEXT7_API_KEY environment variable to be set. API keys start with ctx7sk.

API Endpoint

GET https://context7.com/api/v2/context

Retrieve documentation context for a specific library.

Get Context

Retrieve documentation context for a specific library.

Request:

curl -s "https://context7.com/api/v2/context?libraryId=/facebook/react&query=useEffect" \
  -H "Authorization: Bearer $CONTEXT7_API_KEY"

Response: Plain text/markdown format with code examples and source references:

### Perform Side Effects in React Function Components using useEffect Hook

Source: https://context7.com/facebook/react/llms.txt

The `useEffect` hook enables functional components to perform side effects...

\`\`\`jsx
import { useState, useEffect } from 'react';

function UserProfile({ userId }) {
  // ... code example ...
}
\`\`\`

--------------------------------

### React > Hooks > useEffect

Source: https://context7.com/facebook/react/llms.txt

The `useEffect` hook performs side effects in function components...

Example Usage

# Get documentation for React useEffect hook
curl -s "https://context7.com/api/v2/context?libraryId=/facebook/react&query=useEffect" \
  -H "Authorization: Bearer $CONTEXT7_API_KEY"

# Get documentation for a specific concept
curl -s "https://context7.com/api/v2/context?libraryId=/facebook/react&query=useState%20hook" \
  -H "Authorization: Bearer $CONTEXT7_API_KEY"

# Save to file for reference
curl -s "https://context7.com/api/v2/context?libraryId=/facebook/react&query=hooks" \
  -H "Authorization: Bearer $CONTEXT7_API_KEY" > react-hooks.md

# Search with URL-encoded query
curl -s "https://context7.com/api/v2/context?libraryId=/vercel/next.js&query=app%20router" \
  -H "Authorization: Bearer $CONTEXT7_API_KEY"

Query Parameters

Parameter	Type	Description
libraryId	string	Required. Library identifier (e.g., /facebook/react, /vercel/next.js).
query	string	Required. Natural language query about the documentation topic.

Library ID Format

Library IDs follow the pattern /owner/repo:

Example	Description
/facebook/react	React library
/vercel/next.js	Next.js framework

Response Format

Context Response

The /api/v2/context endpoint returns plain text in markdown format with the following structure:

• Multiple sections separated by --------------------------------
• Each section contains:
  • A heading (e.g., ### Component Name)
  • A Source URL
  • Description text explaining the concept
  • Code examples in fenced code blocks

Example structure:

### Topic Title

Source: https://context7.com/owner/repo/llms.txt

Description text explaining the concept...

\`\`\`language
// Code example
\`\`\`

--------------------------------

### Another Topic

Source: https://github.com/owner/repo/blob/...

More documentation...

Error Handling

Status	Meaning	Action
200	Success	Process normally
202	Accepted - Library not finalized	Wait and retry
301	Moved - Library redirected	Use new ID from redirectUrl
400	Bad Request	Check query parameters
401	Unauthorized - Invalid API key	Verify key (starts with ctx7sk)
403	Forbidden	Check library access permissions
404	Not Found	Verify the library ID
422	Unprocessable - Library too large/no code	Try different library
429	Too Many Requests	Wait for Retry-After header
500	Internal Server Error	Retry with backoff
503	Service Unavailable	Retry later

Rate Limits

• Without API key: Low rate limits, no custom configuration
• With API key: Higher limits based on plan
• View usage at https://context7.com/dashboard

Best Practices

1. Be specific with queries: Use detailed natural language

   # Good
   curl -s ".../context?...&query=How%20to%20implement%20authentication%20with%20middleware"
   
   # Less optimal
   curl -s ".../context?...&query=auth"
   

2. Cache responses: Documentation updates infrequently, cache for hours or days

3. Handle rate limits: Implement exponential backoff for 429 errors

4. Use specific versions: Pin to exact versions for consistent results

   curl -s ".../context?libraryId=/vercel/next.js/v15.1.8&query=..."
   

Always check that CONTEXT7_API_KEY is set before making requests.