Chapter quiz · Fastify Foundations

Test what you learned.

8 questions on Fastify Foundations. Pass 70% to clear the chapter.

Quiz

Fastify Foundations — Chapter Quiz

Eight questions on installing Fastify, routes, async handlers, the reply API, the Pino logger, env config, and TypeScript generics.

0/ 9

Question 1
1
What is Fastify, in one sentence?
AA bundler for Node.js appsBA low-overhead, schema-first Node web frameworkCA serverless platformDA React metaframework
Fastify is a Node.js web framework focused on performance and developer experience, built around JSON Schema for validation and serialization.
Question 2
2
Which package do you install for a minimal Fastify app?
A@fastify/coreBfastify-serverCfastifyD@nodejs/fastify
The framework ships as a single fastify package with no required peer dependencies.
Question 3
3
What status code does this handler return on success?
```
app.get('/', async () => {
  return { hello: 'world' };
});
```
A200B201C204DNo response sent
When an async handler returns a non-undefined value, Fastify sends it as JSON with status 200 by default.
Question 4
4
An async handler that throws an Error will automatically produce a 500 response with a JSON error payload.
TTrueFFalse
Fastify catches thrown errors from async handlers, runs the error hooks, and serializes a JSON error response — by default a 500. Use reply.code(...) or app.httpErrors.* to control the status.
Question 5
5
Which logger does Fastify use out of the box?
AWinstonBBunyanCPinoDconsole.log
Fastify integrates Pino — a fast, JSON-first logger — and exposes it as app.log and request.log.
Question 6
6
To set a 201 status before returning JSON, you write reply.____(201).send(data).
reply.code(201) (or its alias reply.status(201)) sets the HTTP status. Chain .send(...) to send the body, or just return the value from an async handler.
Question 7
7
What does @fastify/env do?
ALoads .env files and validates env vars against a JSON SchemaBConfigures the Node.js environment for productionCGenerates .env.example from your codeDHot-reloads the server on env changes
@fastify/env reads env vars (optionally from a .env file) and validates them against a JSON Schema, exposing the parsed values on app.config.
Question 8
8
Which of these are valid ways to type a request body in TypeScript with Fastify?
Select all that apply.
AGeneric Body parameter on FastifyRequest (e.g. { Body: { x: string } })BA JSON Schema plus TypeBox or json-schema-to-ts for inferenceCA global declare for request.body onlyDCasting request.body as any in every handler
Fastify's route generics ({ Body, Querystring, Params, Reply }) and TypeBox / json-schema-to-ts are the two idiomatic ways. Casting to any defeats the type system; a global declare doesn't scale per route.