What logging strategies would you use to debug issues in a REST API?

• Structured logging with libraries like Serilog, NLog, or built-in ILogger.
• Log requests and responses, including headers and payloads (avoid sensitive info).
• Use correlation IDs to trace requests across services.
• Centralize logs using ELK Stack, Seq, or Azure Application Insights.
• Log different levels: Information, Warning, Error, Critical.

Example using ILogger in ASP.NET Core:

private readonly ILogger<MyController> _logger;

public MyController(ILogger<MyController> logger)

_logger = logger;

[HttpGet("{id}")]

public IActionResult GetUser(int id)

_logger.LogInformation("Fetching user with id {UserId}", id);

try

var user = dbContext.Users.Find(id);

if (user == null)

_logger.LogWarning("User with id {UserId} not found",

id);

return NotFound();

return Ok(user);

catch (Exception ex)

_logger.LogError(ex, "Error fetching user with id {UserId}",

id);

return StatusCode(500, "Internal Server Error");

This covers all core aspects of error handling and debugging for REST APIs.