> For the complete documentation index, see [llms.txt](https://docs.partssource.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.partssource.com/api/core-concepts/correlation-ids.md). # Correlation IDs Track and debug requests using correlation IDs Every API request is assigned a unique correlation ID for tracking and debugging. This identifier helps trace requests through the system and is essential when working with support. *** ## What is a Correlation ID? A correlation ID is a unique identifier assigned to each API request. It appears in: * All API responses (`correlationId` field) * Server-side log entries * Error messages * Support tickets **Example Response:** ```json { "success": true, "data": { "customer": {...} }, "correlationId": "0HN7QJKV3QJ8K:00000001", "timestamp": "2025-10-21T14:30:00.000Z" } ``` *** ## Correlation ID Format ``` 0HN7QJKV3QJ8K:00000001 └─────┬──────┘ └───┬───┘ Connection Request ID Number ``` The format combines a connection identifier with a sequential request number, making it easy to trace related requests within the same session. *** ## Using Correlation IDs ### 1. Log Correlation IDs Always log the correlation ID with your API calls for debugging: ```csharp var response = await httpClient.GetAsync("/api/customers/lookup?userId=123"); var result = await response.Content.ReadFromJsonAsync>(); _logger.LogInformation( "API call completed. Status: {Status}, CorrelationId: {CorrelationId}", response.StatusCode, result.CorrelationId); ``` ### 2. Include in Error Logs When handling errors, always include the correlation ID: ```csharp if (!response.IsSuccessStatusCode) { var error = await response.Content.ReadFromJsonAsync(); _logger.LogError( "API error: {Title}. Status: {Status}. CorrelationId: {CorrelationId}", error.Title, error.Status, error.CorrelationId); // Store for potential support ticket await SaveFailedRequest(error.CorrelationId, requestDetails); } ``` ### 3. Include in Support Requests When contacting support, always include: * The correlation ID * Timestamp of the request * Expected vs. actual behavior **Example support message:** ``` Issue: Order creation returned 500 error CorrelationId: 0HN7QJKV3QJ8K:00000015 Timestamp: 2025-10-21T14:30:00.000Z Environment: Production Expected: Order created successfully Actual: Internal Server Error response ``` *** ## Code Examples ### C\# ```csharp public class ApiLogger { private readonly ILogger _logger; public async Task ExecuteWithLogging( Func> request, string operationName) { var stopwatch = Stopwatch.StartNew(); HttpResponseMessage response = null; try { response = await request(); var content = await response.Content.ReadAsStringAsync(); var result = JsonSerializer.Deserialize>(content); _logger.LogInformation( "API {Operation} completed. Status: {Status}, Duration: {Duration}ms, CorrelationId: {CorrelationId}", operationName, (int)response.StatusCode, stopwatch.ElapsedMilliseconds, result.CorrelationId); if (!result.Success) { throw new ApiException(result.Errors, result.CorrelationId); } return result.Data; } catch (Exception ex) { _logger.LogError(ex, "API {Operation} failed. Status: {Status}, Duration: {Duration}ms", operationName, (int?)response?.StatusCode, stopwatch.ElapsedMilliseconds); throw; } } } ``` ### TypeScript ```typescript interface ApiResponse { success: boolean; data?: T; errors?: string[]; correlationId: string; timestamp: string; } async function fetchWithLogging( url: string, options: RequestInit, operationName: string ): Promise { const startTime = Date.now(); try { const response = await fetch(url, options); const result: ApiResponse = await response.json(); const duration = Date.now() - startTime; console.log(`API ${operationName} completed`, { status: response.status, duration: `${duration}ms`, correlationId: result.correlationId, }); if (!result.success) { throw new ApiError(result.errors, result.correlationId); } return result.data!; } catch (error) { const duration = Date.now() - startTime; console.error(`API ${operationName} failed`, { duration: `${duration}ms`, error: error.message, }); throw error; } } ``` ### Python ```python import logging import time import requests logger = logging.getLogger(__name__) def fetch_with_logging(url, headers, operation_name): start_time = time.time() try: response = requests.get(url, headers=headers) result = response.json() duration_ms = (time.time() - start_time) * 1000 logger.info( f"API {operation_name} completed. " f"Status: {response.status_code}, " f"Duration: {duration_ms:.0f}ms, " f"CorrelationId: {result.get('correlationId')}" ) if not result.get('success'): raise ApiError(result.get('errors'), result.get('correlationId')) return result.get('data') except Exception as e: duration_ms = (time.time() - start_time) * 1000 logger.error( f"API {operation_name} failed. " f"Duration: {duration_ms:.0f}ms, " f"Error: {str(e)}" ) raise ``` *** ## Best Practices ### 1. Store Correlation IDs with Business Transactions ```csharp public class Order { public string OrderId { get; set; } public string ApiCorrelationId { get; set; } // Store for debugging public DateTime CreatedAt { get; set; } } // When creating an order var response = await CreateOrder(orderRequest); order.ApiCorrelationId = response.CorrelationId; await SaveOrder(order); ``` ### 2. Include in Application Logs Structure your logs to make correlation IDs searchable: ```json { "timestamp": "2025-10-21T14:30:00.000Z", "level": "info", "message": "Order created successfully", "orderId": "ORD-12345", "apiCorrelationId": "0HN7QJKV3QJ8K:00000001", "userId": "jsmith" } ``` ### 3. Create a Correlation ID Index For high-volume integrations, maintain an index of correlation IDs: ```sql CREATE INDEX idx_api_correlation ON api_requests(correlation_id); -- Query for debugging SELECT * FROM api_requests WHERE correlation_id = '0HN7QJKV3QJ8K:00000001'; ``` *** ## Troubleshooting with Correlation IDs When debugging an issue: 1. **Find the correlation ID** from your logs or error response 2. **Note the timestamp** of when the error occurred 3. **Gather context** - what operation was being performed? 4. **Contact support** with all this information Support can use the correlation ID to: * Find the exact request in server logs * See what data was sent and received * Identify where in the processing pipeline an error occurred * Trace the request through multiple internal services --- # Agent Instructions This documentation is published with GitBook. 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