diff --git a/generate-swagger.js b/generate-swagger.js
index 9ef87eeb..090c8227 100644
--- a/generate-swagger.js
+++ b/generate-swagger.js
@@ -13,6 +13,9 @@ const {
 } = require('./util')
 const fp = require('fastify-plugin')
 const { loadEnvQuitely } = require('./env-loader')
+const deepmerge = require('@fastify/deepmerge')({
+  cloneProtoObject (obj) { return obj }
+})
 
 let Fastify = null
 
@@ -66,7 +69,13 @@ async function runFastify (opts) {
     return module.exports.stop(e)
   }
 
-  const fastify = Fastify(opts.options)
+  let options = {}
+
+  if (opts.options && file.options) {
+    options = deepmerge(options, file.options)
+  }
+
+  const fastify = Fastify(options)
 
   const pluginOptions = {}
   if (opts.prefix) {
diff --git a/help/generate-swagger.txt b/help/generate-swagger.txt
index 06ebf355..c641f846 100644
--- a/help/generate-swagger.txt
+++ b/help/generate-swagger.txt
@@ -6,3 +6,7 @@ OPTS
 
   --yaml=true
       generate in YAML format
+
+  -o, --options
+  [env: FASTIFY_OPTIONS]
+      Use custom options
diff --git a/test/generate-swagger.test.js b/test/generate-swagger.test.js
index f03ff405..792f19a8 100644
--- a/test/generate-swagger.test.js
+++ b/test/generate-swagger.test.js
@@ -28,3 +28,25 @@ test('should generate swagger in yaml format', async (t) => {
     t.assert.ifError(err)
   }
 })
+
+test('should not use custom options by default', async (t) => {
+  t.plan(1)
+
+  try {
+    const swagger = JSON.parse(await generateSwagger([swaggerplugin]))
+    t.assert.equal(swagger.info.description, 'Body limit: 1048576')
+  } catch (err) {
+    t.assert.ifError(err)
+  }
+})
+
+test('should use custom options', async (t) => {
+  t.plan(1)
+
+  try {
+    const swagger = JSON.parse(await generateSwagger(['-o', swaggerplugin]))
+    t.assert.equal(swagger.info.description, 'Body limit: 2097152')
+  } catch (err) {
+    t.assert.ifError(err)
+  }
+})
diff --git a/test/swaggerplugindir/plugin.js b/test/swaggerplugindir/plugin.js
index fee6af1e..ac7278a3 100644
--- a/test/swaggerplugindir/plugin.js
+++ b/test/swaggerplugindir/plugin.js
@@ -8,10 +8,11 @@ module.exports = fp(function (fastify, opts, next) {
       return `\
 openapi: 3.0.3
 info:
-version: 8.1.0
-title: "@fastify/swagger"
+  version: 8.1.0
+  title: "@fastify/swagger"
+  description: "Body limit: ${fastify.initialConfig.bodyLimit}"
 components:
-schemas: {}
+  schemas: {}
 paths:
 "/":
   get:
@@ -29,7 +30,8 @@ paths:
         openapi: '3.0.3',
         info: {
           version: '8.1.0',
-          title: '@fastify/swagger'
+          title: '@fastify/swagger',
+          description: `Body limit: ${fastify.initialConfig.bodyLimit}`
         },
         components: {
           schemas: {}
@@ -59,3 +61,7 @@ paths:
   })
   next()
 })
+
+module.exports.options = {
+  bodyLimit: 2097152
+}