How do you implement a filter that adds a request correlation ID to every error response in NestJS?

Q: How do you implement a filter that adds a request correlation ID to every error response in NestJS?

import { randomUUID } from 'crypto'; @Catch() export class CorrelationIdFilter implements ExceptionFilter { catch(exception: unknown, host: ArgumentsHost): void { const ctx = host.switchToHttp(); const req = ctx.getRequest (); const res = ctx.getResponse (); // Read from incoming header or generate a new ID const correlationId = (req.headers['x-correlation-id'] as string) ?? randomUUID(); const status = exception instanceof HttpException ? exception.getStatus() : 500; const message = exception instanceof HttpException ? exception.message : 'Internal server error'; // Echo the ID in the response header res.setHeader('X-Correlation-Id', correlationId); res.status(status).json({ statusCode: status, message, correlationId, // include in body for client-side log correlation timestamp: new Date().toISOString(), }); } } Upstream API gateways (AWS ALB, nginx) often inject x-correlation-id — always read it if present. Fall back to randomUUID() so every error response has a trackable ID even without a gateway. Set the ID in both the response header and body — some clients read headers, others parse the body. Pair with a middleware that attaches the correlation ID to req at the start of every request lifecycle. Log the correlation ID alongside every error so server logs and client error reports can be joined.

Difficulty: 5/10

Exception Filters, Correlation ID, Error Handling

Read the correlation ID from the incoming request header — set by upstream infrastructure or a middleware. Fall back to generating a new UUID if absent. Echo the ID back in both the response header and the response body so clients can correlate errors with distributed logs.

Exception filter with correlation ID propagation

Correlation ID best practices:

1
Upstream API gateways (AWS ALB, nginx) often inject x-correlation-id — always read it if present.
2

How do you implement a filter that adds a request correlation ID to every error response in NestJS?

Difficulty: 5/10

Exception Filters, Correlation ID, Error Handling

Read the correlation ID from the incoming request header — set by upstream infrastructure or a middleware. Fall back to generating a new UUID if absent. Echo the ID back in both the response header and the response body so clients can correlate errors with distributed logs.

Exception filter with correlation ID propagation

Correlation ID best practices:

1
Upstream API gateways (AWS ALB, nginx) often inject x-correlation-id — always read it if present.
2

How do you implement a filter that adds a request correlation ID to every error response in NestJS?

Read the correlation ID from the incoming request header — set by upstream infrastructure or a middleware. Fall back to generating a new UUID if absent. Echo the ID back in both the response header and the response body so clients can correlate errors with distributed logs.

How do you implement a filter that adds a request correlation ID to every error response in NestJS?

Read the correlation ID from the incoming request header — set by upstream infrastructure or a middleware. Fall back to generating a new UUID if absent. Echo the ID back in both the response header and the response body so clients can correlate errors with distributed logs.

Scenario Questions

Follow-up Questions