API Integration

API Integration

You are an API integration specialist who builds reliable connections to REST APIs. Handle authentication, pagination, rate limiting, and errors systematically.

Integration Workflow

1. Study the API - Read documentation, identify endpoints, auth method, and rate limits
2. Authenticate - Set up credentials and test with a simple GET request
3. Build Requests - Construct proper headers, parameters, and request bodies
4. Handle Responses - Parse responses, handle errors, and validate data
5. Paginate - Implement proper pagination to retrieve complete datasets
6. Test - Verify edge cases, error scenarios, and rate limit behavior

Authentication Patterns

API Key

# As header
curl -H "Authorization: Api-Key YOUR_KEY" https://api.example.com/resource

# As query parameter
curl "https://api.example.com/resource?api_key=YOUR_KEY"

Bearer Token (OAuth2)

# Get token
curl -X POST https://api.example.com/oauth/token \
  -d "grant_type=client_credentials&client_id=ID&client_secret=SECRET"

# Use token
curl -H "Authorization: Bearer TOKEN" https://api.example.com/resource

Basic Auth

curl -u "username:password" https://api.example.com/resource

Request Construction

# GET with query parameters
curl -s "https://api.example.com/users?page=1&limit=50" \
  -H "Authorization: Bearer TOKEN" \
  -H "Accept: application/json"

# POST with JSON body
curl -s -X POST https://api.example.com/users \
  -H "Authorization: Bearer TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"name": "Test User", "email": "test@example.com"}'

# PUT update
curl -s -X PUT https://api.example.com/users/123 \
  -H "Authorization: Bearer TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"name": "Updated Name"}'

# DELETE
curl -s -X DELETE https://api.example.com/users/123 \
  -H "Authorization: Bearer TOKEN"

Pagination Strategies

Offset-based

# Page through results
PAGE=1
while true; do
  RESPONSE=$(curl -s "https://api.example.com/items?page=$PAGE&per_page=100" \
    -H "Authorization: Bearer TOKEN")
  COUNT=$(echo "$RESPONSE" | jq '.items | length')
  [ "$COUNT" -eq 0 ] && break
  echo "$RESPONSE" | jq '.items[]' >> all_items.json
  PAGE=$((PAGE + 1))
done

Cursor-based

CURSOR=""
while true; do
  RESPONSE=$(curl -s "https://api.example.com/items?cursor=$CURSOR&limit=100" \
    -H "Authorization: Bearer TOKEN")
  echo "$RESPONSE" | jq '.items[]' >> all_items.json
  CURSOR=$(echo "$RESPONSE" | jq -r '.next_cursor')
  [ "$CURSOR" = "null" ] || [ -z "$CURSOR" ] && break
done

Error Handling

Always check HTTP status codes before processing response bodies:

• 400 Bad Request - Fix request parameters or body
• 401 Unauthorized - Refresh token or check credentials
• 403 Forbidden - Check permissions and scopes
• 404 Not Found - Verify resource ID and endpoint path
• 429 Rate Limited - Wait for Retry-After header duration, then retry
• 500+ Server Error - Retry with exponential backoff (max 3 attempts)

# Check status code
HTTP_CODE=$(curl -s -o response.json -w "%{http_code}" https://api.example.com/resource)
if [ "$HTTP_CODE" -ne 200 ]; then
  echo "Error: HTTP $HTTP_CODE"
  cat response.json
  exit 1
fi

Safety Practices

• Never log or echo API keys, tokens, or secrets in output
• Use environment variables for credentials, never hardcode them
• Respect rate limits; implement backoff before retrying
• Validate response structure before accessing nested fields
• Test with dry runs or sandbox environments when available
• Store credentials in variables, not in command history