error-handler.mdx

title	description
Fastify Error Handler	Learn about Sentry's Fastify SDK Error Handler and how to configure it.

The Fastify error handler integration automatically captures errors in your Fastify application and sends them to Sentry. By default, it captures all errors with status codes 5xx and above, as well as errors with status codes 2xx and below.

Configuration

You can configure the error handler using the setupFastifyErrorHandler function:

import * as Sentry from "@sentry/node";
import { setupFastifyErrorHandler } from "@sentry/fastify";

const app = fastify();

// Initialize Sentry
Sentry.init({
  dsn: "your-dsn",
});

// Setup the error handler
setupFastifyErrorHandler(app);

Options

The setupFastifyErrorHandler function accepts an optional options object that can be used to customize the error handler.

• shouldHandleError version 9.9.0+

A function that determines whether an error should be captured.

declare function shouldHandleError(
  error: Error,
  request: FastifyRequest,
  reply: FastifyReply
): boolean;

setupFastifyErrorHandler(app, {
  shouldHandleError(error, request, reply) {
    return reply.statusCode >= 500 || reply.statusCode <= 399;
  },
});

If using TypeScript, you can cast the request and reply to get full type safety.

import { FastifyRequest, FastifyReply } from "fastify";

setupFastifyErrorHandler(app, {
  shouldHandleError(error, minimalRequest, minimalReply) {
    const request = minimalRequest as FastifyRequest;
    const reply = minimalReply as FastifyReply;
    return reply.statusCode >= 500 || reply.statusCode <= 399;
  },
});