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fastifyApiUi

Fastify plugin factory that mounts the @opra/api-ui reference page as a Fastify plugin, registered with app.register().

import { fastifyApiUi } from '@opra/api-ui';

Signature​

function fastifyApiUi(
  document: ApiDocument,
  options?: ApiUiOptions,
): FastifyPluginAsync

Returns a Fastify plugin (compatible with app.register(plugin, { prefix })).

Usage​

import Fastify from 'fastify';
import { fastifyApiUi } from '@opra/api-ui';

const app = Fastify();

app.register(fastifyApiUi(apiDocument, {
  pageTitle: 'My API',
}), { prefix: '/reference' });

With scope selector​

app.register(fastifyApiUi(apiDocument, {
  scopes: ['public', 'internal'],
}), { prefix: '/reference' });
// GET /reference/public/  → public scope
// GET /reference/internal/ → internal scope

Fastify specifics​

Unlike Express, Fastify does not strip the mount prefix from req.url. fastifyApiUi reads the full prefix from instance.prefix (which includes all parent prefixes) and passes it to the underlying handler correctly. Responses are delivered via reply.hijack() on the raw Node.js socket, bypassing Fastify's serialization.

See also​