Error handling

Authentify It implements a centralized and structured error handling strategy to ensure system resilience, developer observability, and client transparency.

General Methods

• try/catch blocks are used in critical services to capture and gracefully handle unexpected errors.

• Centralized exception filters in NestJS provide a unified mechanism to process, log, and format errors before sending them back to clients.

• This guarantees that sensitive system details are never exposed, while still providing clients with actionable information.

Example: centralized exception filter in NestJS

import { ExceptionFilter, Catch, ArgumentsHost, HttpException, HttpStatus, Logger } from '@nestjs/common';

@Catch()
export class AllExceptionsFilter implements ExceptionFilter {
  private readonly logger = new Logger(AllExceptionsFilter.name);

  catch(exception: unknown, host: ArgumentsHost) {
    const ctx = host.switchToHttp();
    const response = ctx.getResponse();

    const status =
      exception instanceof HttpException
        ? exception.getStatus()
        : HttpStatus.INTERNAL_SERVER_ERROR;

    const message =
      exception instanceof HttpException ? exception.getResponse() : exception;

    // Log error internally (can be sent to Sentry, Slack, etc.)
    this.logger.error(`Error occurred: ${JSON.stringify(message)}`);

    // Return safe error response to client
    response.status(status).json({
      statusCode: status,
      timestamp: new Date().toISOString(),
      message,
    });
  }
}

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Error Types

• Internal Errors (500)

  • Logged in detail.

  • Alerts sent to Sentry for real-time monitoring.

  • Sanitized response returned to clients to prevent information leakage.

• Client Errors (400, 401, 403, etc.)

  • Handled explicitly within business logic and controllers.

  • Returned to clients with clear, descriptive messages (e.g., invalid input, unauthorized access).