diff --git a/index.js b/index.js
index 4732f50..f9ec675 100644
--- a/index.js
+++ b/index.js
@@ -8,6 +8,8 @@ const kGenerateCallbackUriParams = Symbol.for('fastify-oauth2.generate-callback-
 
 const { promisify, callbackify } = require('util')
 
+const USER_AGENT = 'fastify-oauth2'
+
 function defaultGenerateStateFunction () {
   return randomBytes(16).toString('base64url')
 }
@@ -69,6 +71,9 @@ function fastifyOauth2 (fastify, options, next) {
   if (options.cookie && typeof options.cookie !== 'object') {
     return next(new Error('options.cookie should be an object'))
   }
+  if (options.userAgent && typeof options.userAgent !== 'string') {
+    return next(new Error('options.userAgent should be a string'))
+  }
 
   if (!fastify.hasReplyDecorator('cookie')) {
     fastify.register(require('@fastify/cookie'))
@@ -76,7 +81,6 @@ function fastifyOauth2 (fastify, options, next) {
 
   const {
     name,
-    credentials,
     callbackUri,
     callbackUriParams = {},
     tokenRequestParams = {},
@@ -88,6 +92,19 @@ function fastifyOauth2 (fastify, options, next) {
     schema = { tags }
   } = options
 
+  const userAgent = options.userAgent === false
+    ? undefined
+    : (options.userAgent || USER_AGENT)
+  const credentials = {
+    ...options.credentials,
+    http: {
+      ...options.credentials.http,
+      headers: {
+        'User-Agent': userAgent,
+        ...options.credentials.http?.headers
+      }
+    }
+  }
   const generateCallbackUriParams = (credentials.auth && credentials.auth[kGenerateCallbackUriParams]) || defaultGenerateCallbackUriParams
   const cookieOpts = Object.assign({ httpOnly: true, sameSite: 'lax' }, options.cookie)
 
diff --git a/package.json b/package.json
index 0f6a964..8f8c071 100644
--- a/package.json
+++ b/package.json
@@ -8,7 +8,7 @@
     "lint": "standard | snazzy",
     "lint:fix": "standard --fix",
     "test": "npm run test:unit && npm run test:typescript",
-    "test:coverage": "npm run unit -- --cov --coverage-report=html",
+    "test:coverage": "npm run test:unit -- --cov --coverage-report=html",
     "test:typescript": "tsd",
     "test:unit": "tap"
   },
diff --git a/test/index.test.js b/test/index.test.js
index f1bbd4a..635c7f9 100644
--- a/test/index.test.js
+++ b/test/index.test.js
@@ -8,7 +8,7 @@ const fastifyOauth2 = require('..')
 
 nock.disableNetConnect()
 
-function makeRequests (t, fastify) {
+function makeRequests (t, fastify, userAgentHeaderMatcher) {
   fastify.listen({ port: 0 }, function (err) {
     t.error(err)
 
@@ -39,17 +39,11 @@ function makeRequests (t, fastify) {
       }
 
       const githubScope = nock('https://github.com')
-        .post('/login/oauth/access_token', 'grant_type=authorization_code&code=my-code&redirect_uri=http%3A%2F%2Flocalhost%3A3000%2Fcallback', {
-          reqheaders: {
-            authorization: 'Basic bXktY2xpZW50LWlkOm15LXNlY3JldA=='
-          }
-        })
+        .matchHeader('Authorization', 'Basic bXktY2xpZW50LWlkOm15LXNlY3JldA==')
+        .matchHeader('User-Agent', userAgentHeaderMatcher || 'fastify-oauth2')
+        .post('/login/oauth/access_token', 'grant_type=authorization_code&code=my-code&redirect_uri=http%3A%2F%2Flocalhost%3A3000%2Fcallback')
         .reply(200, RESPONSE_BODY)
-        .post('/login/oauth/access_token', 'grant_type=refresh_token&refresh_token=my-refresh-token', {
-          reqheaders: {
-            authorization: 'Basic bXktY2xpZW50LWlkOm15LXNlY3JldA=='
-          }
-        })
+        .post('/login/oauth/access_token', 'grant_type=refresh_token&refresh_token=my-refresh-token')
         .reply(200, RESPONSE_BODY_REFRESHED)
 
       fastify.inject({
@@ -192,6 +186,128 @@ t.test('fastify-oauth2', t => {
     })
   })
 
+  t.test('custom user-agent', t => {
+    const fastify = createFastify({ logger: { level: 'silent' } })
+
+    fastify.register(fastifyOauth2, {
+      name: 'githubOAuth2',
+      credentials: {
+        client: {
+          id: 'my-client-id',
+          secret: 'my-secret'
+        },
+        auth: fastifyOauth2.GITHUB_CONFIGURATION
+      },
+      startRedirectPath: '/login/github',
+      callbackUri: 'http://localhost:3000/callback',
+      scope: ['notifications'],
+      userAgent: 'test/1.2.3'
+    })
+
+    fastify.get('/', function (request, reply) {
+      return this.githubOAuth2.getAccessTokenFromAuthorizationCodeFlow(request)
+        .then(result => {
+          // attempts to refresh the token
+          return this.githubOAuth2.getNewAccessTokenUsingRefreshToken(result.token)
+        })
+        .then(token => {
+          return {
+            access_token: token.token.access_token,
+            refresh_token: token.token.refresh_token,
+            expires_in: token.token.expires_in,
+            token_type: token.token.token_type
+          }
+        })
+    })
+
+    t.teardown(fastify.close.bind(fastify))
+
+    makeRequests(t, fastify, 'test/1.2.3')
+  })
+
+  t.test('overridden user-agent', t => {
+    const fastify = createFastify({ logger: { level: 'silent' } })
+
+    fastify.register(fastifyOauth2, {
+      name: 'githubOAuth2',
+      credentials: {
+        client: {
+          id: 'my-client-id',
+          secret: 'my-secret'
+        },
+        auth: fastifyOauth2.GITHUB_CONFIGURATION,
+        http: {
+          headers: {
+            'User-Agent': 'foo/4.5.6'
+          }
+        }
+      },
+      startRedirectPath: '/login/github',
+      callbackUri: 'http://localhost:3000/callback',
+      scope: ['notifications'],
+      userAgent: 'test/1.2.3'
+    })
+
+    fastify.get('/', function (request, reply) {
+      return this.githubOAuth2.getAccessTokenFromAuthorizationCodeFlow(request)
+        .then(result => {
+          // attempts to refresh the token
+          return this.githubOAuth2.getNewAccessTokenUsingRefreshToken(result.token)
+        })
+        .then(token => {
+          return {
+            access_token: token.token.access_token,
+            refresh_token: token.token.refresh_token,
+            expires_in: token.token.expires_in,
+            token_type: token.token.token_type
+          }
+        })
+    })
+
+    t.teardown(fastify.close.bind(fastify))
+
+    makeRequests(t, fastify, /^foo\/4\.5\.6$/)
+  })
+
+  t.test('disabled user-agent', t => {
+    const fastify = createFastify({ logger: { level: 'silent' } })
+
+    fastify.register(fastifyOauth2, {
+      name: 'githubOAuth2',
+      credentials: {
+        client: {
+          id: 'my-client-id',
+          secret: 'my-secret'
+        },
+        auth: fastifyOauth2.GITHUB_CONFIGURATION
+      },
+      startRedirectPath: '/login/github',
+      callbackUri: 'http://localhost:3000/callback',
+      scope: ['notifications'],
+      userAgent: false
+    })
+
+    fastify.get('/', function (request, reply) {
+      return this.githubOAuth2.getAccessTokenFromAuthorizationCodeFlow(request)
+        .then(result => {
+          // attempts to refresh the token
+          return this.githubOAuth2.getNewAccessTokenUsingRefreshToken(result.token)
+        })
+        .then(token => {
+          return {
+            access_token: token.token.access_token,
+            refresh_token: token.token.refresh_token,
+            expires_in: token.token.expires_in,
+            token_type: token.token.token_type
+          }
+        })
+    })
+
+    t.teardown(fastify.close.bind(fastify))
+
+    makeRequests(t, fastify, userAgent => userAgent === undefined)
+  })
+
   t.end()
 })
 
@@ -624,6 +740,28 @@ t.test('options.cookie should be an object', t => {
     })
 })
 
+t.test('options.userAgent should be a string', t => {
+  t.plan(1)
+
+  const fastify = createFastify({ logger: { level: 'silent' } })
+
+  fastify.register(fastifyOauth2, {
+    name: 'the-name',
+    credentials: {
+      client: {
+        id: 'my-client-id',
+        secret: 'my-secret'
+      },
+      auth: fastifyOauth2.GITHUB_CONFIGURATION
+    },
+    callbackUri: '/callback',
+    userAgent: 1
+  })
+    .ready(err => {
+      t.strictSame(err.message, 'options.userAgent should be a string')
+    })
+})
+
 t.test('options.schema', t => {
   const fastify = createFastify({ logger: { level: 'silent' }, exposeHeadRoutes: false })
 
diff --git a/types/index.d.ts b/types/index.d.ts
index eef2b11..5ed0543 100644
--- a/types/index.d.ts
+++ b/types/index.d.ts
@@ -33,6 +33,7 @@ declare namespace fastifyOauth2 {
     tags?: string[];
     schema?: object;
     cookie?: CookieSerializeOptions;
+    userAgent?: string | false;
   }
 
     export type TToken = 'access_token' | 'refresh_token'