diff --git a/packages/backend/src/plugins/app.ts b/packages/backend/src/plugins/app.ts
index 637af80974..5ee616b62f 100644
--- a/packages/backend/src/plugins/app.ts
+++ b/packages/backend/src/plugins/app.ts
@@ -15,12 +15,13 @@
  */
 
 import { createRouter } from '@backstage/plugin-app-backend';
+import { Router } from 'express';
 import { PluginEnvironment } from '../types';
 
 export default async function createPlugin({
   logger,
   config,
-}: PluginEnvironment) {
+}: PluginEnvironment): Promise<Router> {
   return await createRouter({
     logger,
     config,
diff --git a/packages/backend/src/plugins/auth.ts b/packages/backend/src/plugins/auth.ts
index 913c8b783d..2b1c85f052 100644
--- a/packages/backend/src/plugins/auth.ts
+++ b/packages/backend/src/plugins/auth.ts
@@ -15,6 +15,7 @@
  */
 
 import { createRouter } from '@backstage/plugin-auth-backend';
+import { Router } from 'express';
 import { PluginEnvironment } from '../types';
 
 export default async function createPlugin({
@@ -22,6 +23,6 @@ export default async function createPlugin({
   database,
   config,
   discovery,
-}: PluginEnvironment) {
+}: PluginEnvironment): Promise<Router> {
   return await createRouter({ logger, config, database, discovery });
 }
diff --git a/packages/backend/src/plugins/catalog.ts b/packages/backend/src/plugins/catalog.ts
index 1338fab440..eaca42717c 100644
--- a/packages/backend/src/plugins/catalog.ts
+++ b/packages/backend/src/plugins/catalog.ts
@@ -20,9 +20,12 @@ import {
   createRouter,
   runPeriodically,
 } from '@backstage/plugin-catalog-backend';
+import { Router } from 'express';
 import { PluginEnvironment } from '../types';
 
-export default async function createPlugin(env: PluginEnvironment) {
+export default async function createPlugin(
+  env: PluginEnvironment,
+): Promise<Router> {
   const builder = new CatalogBuilder(env);
   const {
     entitiesCatalog,
diff --git a/packages/backend/src/plugins/graphql.ts b/packages/backend/src/plugins/graphql.ts
index d52e28f9cb..c7f5d6e072 100644
--- a/packages/backend/src/plugins/graphql.ts
+++ b/packages/backend/src/plugins/graphql.ts
@@ -13,29 +13,15 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-/*
- * Copyright 2020 Spotify AB
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
 
 import { createRouter } from '@backstage/plugin-graphql-backend';
+import { Router } from 'express';
 import { PluginEnvironment } from '../types';
 
 export default async function createPlugin({
   logger,
   config,
-}: PluginEnvironment) {
+}: PluginEnvironment): Promise<Router> {
   return await createRouter({
     logger,
     config,
diff --git a/packages/backend/src/plugins/healthcheck.ts b/packages/backend/src/plugins/healthcheck.ts
index 3dd9a67827..8ecae6be87 100644
--- a/packages/backend/src/plugins/healthcheck.ts
+++ b/packages/backend/src/plugins/healthcheck.ts
@@ -15,8 +15,11 @@
  */
 
 import { createStatusCheckRouter } from '@backstage/backend-common';
+import { Router } from 'express';
 import { PluginEnvironment } from '../types';
 
-export default async function createRouter({ logger }: PluginEnvironment) {
+export default async function createRouter({
+  logger,
+}: PluginEnvironment): Promise<Router> {
   return await createStatusCheckRouter({ logger, path: '/healthcheck' });
 }
diff --git a/packages/backend/src/plugins/kafka.ts b/packages/backend/src/plugins/kafka.ts
index e65ce6719c..d5b5857027 100644
--- a/packages/backend/src/plugins/kafka.ts
+++ b/packages/backend/src/plugins/kafka.ts
@@ -15,11 +15,12 @@
  */
 
 import { createRouter } from '@backstage/plugin-kafka-backend';
+import { Router } from 'express';
 import { PluginEnvironment } from '../types';
 
 export default async function createPlugin({
   logger,
   config,
-}: PluginEnvironment) {
+}: PluginEnvironment): Promise<Router> {
   return await createRouter({ logger, config });
 }
diff --git a/packages/backend/src/plugins/kubernetes.ts b/packages/backend/src/plugins/kubernetes.ts
index 7906765533..131c5c8eee 100644
--- a/packages/backend/src/plugins/kubernetes.ts
+++ b/packages/backend/src/plugins/kubernetes.ts
@@ -15,11 +15,12 @@
  */
 
 import { createRouter } from '@backstage/plugin-kubernetes-backend';
+import { Router } from 'express';
 import { PluginEnvironment } from '../types';
 
 export default async function createPlugin({
   logger,
   config,
-}: PluginEnvironment) {
+}: PluginEnvironment): Promise<Router> {
   return await createRouter({ logger, config });
 }
diff --git a/packages/backend/src/plugins/proxy.ts b/packages/backend/src/plugins/proxy.ts
index 867e742dc0..8c5e3284c0 100644
--- a/packages/backend/src/plugins/proxy.ts
+++ b/packages/backend/src/plugins/proxy.ts
@@ -14,14 +14,14 @@
  * limitations under the License.
  */
 
-// @ts-ignore
 import { createRouter } from '@backstage/plugin-proxy-backend';
+import { Router } from 'express';
 import { PluginEnvironment } from '../types';
 
 export default async function createPlugin({
   logger,
   config,
   discovery,
-}: PluginEnvironment) {
+}: PluginEnvironment): Promise<Router> {
   return await createRouter({ logger, config, discovery });
 }
diff --git a/packages/backend/src/plugins/rollbar.ts b/packages/backend/src/plugins/rollbar.ts
index c6a2c27e9b..b510346af5 100644
--- a/packages/backend/src/plugins/rollbar.ts
+++ b/packages/backend/src/plugins/rollbar.ts
@@ -15,11 +15,12 @@
  */
 
 import { createRouter } from '@backstage/plugin-rollbar-backend';
+import { Router } from 'express';
 import type { PluginEnvironment } from '../types';
 
 export default async function createPlugin({
   logger,
   config,
-}: PluginEnvironment) {
+}: PluginEnvironment): Promise<Router> {
   return await createRouter({ logger, config });
 }
diff --git a/packages/backend/src/plugins/scaffolder.ts b/packages/backend/src/plugins/scaffolder.ts
index 10da5f0e15..1b97f735a0 100644
--- a/packages/backend/src/plugins/scaffolder.ts
+++ b/packages/backend/src/plugins/scaffolder.ts
@@ -14,24 +14,25 @@
  * limitations under the License.
  */
 
+import { SingleHostDiscovery } from '@backstage/backend-common';
+import { CatalogClient } from '@backstage/catalog-client';
 import {
   CookieCutter,
+  CreateReactAppTemplater,
   createRouter,
   Preparers,
   Publishers,
-  CreateReactAppTemplater,
   Templaters,
 } from '@backstage/plugin-scaffolder-backend';
-import { SingleHostDiscovery } from '@backstage/backend-common';
-import type { PluginEnvironment } from '../types';
 import Docker from 'dockerode';
-import { CatalogClient } from '@backstage/catalog-client';
+import { Router } from 'express';
+import type { PluginEnvironment } from '../types';
 
 export default async function createPlugin({
   logger,
   config,
   database,
-}: PluginEnvironment) {
+}: PluginEnvironment): Promise<Router> {
   const cookiecutterTemplater = new CookieCutter();
   const craTemplater = new CreateReactAppTemplater();
   const templaters = new Templaters();
diff --git a/packages/backend/src/plugins/techdocs.ts b/packages/backend/src/plugins/techdocs.ts
index afe92cc347..9883f2afbc 100644
--- a/packages/backend/src/plugins/techdocs.ts
+++ b/packages/backend/src/plugins/techdocs.ts
@@ -15,19 +15,20 @@
  */
 import {
   createRouter,
-  Preparers,
   Generators,
+  Preparers,
   Publisher,
 } from '@backstage/plugin-techdocs-backend';
-import { PluginEnvironment } from '../types';
 import Docker from 'dockerode';
+import { Router } from 'express';
+import { PluginEnvironment } from '../types';
 
 export default async function createPlugin({
   logger,
   config,
   discovery,
   reader,
-}: PluginEnvironment) {
+}: PluginEnvironment): Promise<Router> {
   // Preparers are responsible for fetching source files for documentation.
   const preparers = await Preparers.fromConfig(config, {
     logger,
diff --git a/packages/cli/package.json b/packages/cli/package.json
index 4a95df0f38..d0f78c90a2 100644
--- a/packages/cli/package.json
+++ b/packages/cli/package.json
@@ -52,7 +52,7 @@
     "@types/start-server-webpack-plugin": "^2.2.0",
     "@types/webpack-env": "^1.15.2",
     "@types/webpack-node-externals": "^2.5.0",
-    "@typescript-eslint/eslint-plugin": "^v4.14.0",
+    "@typescript-eslint/eslint-plugin": "^v4.15.2",
     "@typescript-eslint/parser": "^v4.14.0",
     "@yarnpkg/lockfile": "^1.1.0",
     "babel-plugin-dynamic-import-node": "^2.3.3",
diff --git a/packages/create-app/templates/default-app/packages/backend/src/plugins/app.ts b/packages/create-app/templates/default-app/packages/backend/src/plugins/app.ts
index 51316949cb..07fb04fca2 100644
--- a/packages/create-app/templates/default-app/packages/backend/src/plugins/app.ts
+++ b/packages/create-app/templates/default-app/packages/backend/src/plugins/app.ts
@@ -1,10 +1,11 @@
 import { createRouter } from '@backstage/plugin-app-backend';
+import { Router } from 'express';
 import { PluginEnvironment } from '../types';
 
 export default async function createPlugin({
   logger,
   config,
-}: PluginEnvironment) {
+}: PluginEnvironment): Promise<Router> {
   return await createRouter({
     logger,
     config,
diff --git a/packages/create-app/templates/default-app/packages/backend/src/plugins/auth.ts b/packages/create-app/templates/default-app/packages/backend/src/plugins/auth.ts
index fe19855d5d..52165104a2 100644
--- a/packages/create-app/templates/default-app/packages/backend/src/plugins/auth.ts
+++ b/packages/create-app/templates/default-app/packages/backend/src/plugins/auth.ts
@@ -1,4 +1,5 @@
 import { createRouter } from '@backstage/plugin-auth-backend';
+import { Router } from 'express';
 import { PluginEnvironment } from '../types';
 
 export default async function createPlugin({
@@ -6,6 +7,6 @@ export default async function createPlugin({
   database,
   config,
   discovery,
-}: PluginEnvironment) {
+}: PluginEnvironment): Promise<Router> {
   return await createRouter({ logger, config, database, discovery });
 }
diff --git a/packages/create-app/templates/default-app/packages/backend/src/plugins/catalog.ts b/packages/create-app/templates/default-app/packages/backend/src/plugins/catalog.ts
index 10ac116ded..883b70c587 100644
--- a/packages/create-app/templates/default-app/packages/backend/src/plugins/catalog.ts
+++ b/packages/create-app/templates/default-app/packages/backend/src/plugins/catalog.ts
@@ -2,11 +2,12 @@ import { useHotCleanup } from '@backstage/backend-common';
 import {
   CatalogBuilder,
   createRouter,
-  runPeriodically,
+  runPeriodically
 } from '@backstage/plugin-catalog-backend';
+import { Router } from 'express';
 import { PluginEnvironment } from '../types';
 
-export default async function createPlugin(env: PluginEnvironment) {
+export default async function createPlugin(env: PluginEnvironment): Promise<Router> {
   const builder = new CatalogBuilder(env);
   const {
     entitiesCatalog,
diff --git a/packages/create-app/templates/default-app/packages/backend/src/plugins/proxy.ts b/packages/create-app/templates/default-app/packages/backend/src/plugins/proxy.ts
index 388d3fc446..506f6d98f9 100644
--- a/packages/create-app/templates/default-app/packages/backend/src/plugins/proxy.ts
+++ b/packages/create-app/templates/default-app/packages/backend/src/plugins/proxy.ts
@@ -1,11 +1,11 @@
-// @ts-ignore
 import { createRouter } from '@backstage/plugin-proxy-backend';
+import { Router } from 'express';
 import { PluginEnvironment } from '../types';
 
 export default async function createPlugin({
   logger,
   config,
   discovery,
-}: PluginEnvironment) {
+}: PluginEnvironment): Promise<Router> {
   return await createRouter({ logger, config, discovery });
 }
diff --git a/packages/create-app/templates/default-app/packages/backend/src/plugins/scaffolder.ts b/packages/create-app/templates/default-app/packages/backend/src/plugins/scaffolder.ts
index 6f42aaa327..49cd8a9cda 100644
--- a/packages/create-app/templates/default-app/packages/backend/src/plugins/scaffolder.ts
+++ b/packages/create-app/templates/default-app/packages/backend/src/plugins/scaffolder.ts
@@ -1,21 +1,25 @@
+import { SingleHostDiscovery } from '@backstage/backend-common';
+import { CatalogClient } from '@backstage/catalog-client';
 import {
   CookieCutter,
-  createRouter,
+
+
+
+  CreateReactAppTemplater, createRouter,
   Preparers,
   Publishers,
-  CreateReactAppTemplater,
-  Templaters,
+
+  Templaters
 } from '@backstage/plugin-scaffolder-backend';
-import { SingleHostDiscovery } from '@backstage/backend-common';
-import type { PluginEnvironment } from '../types';
 import Docker from 'dockerode';
-import { CatalogClient } from '@backstage/catalog-client';
+import { Router } from 'express';
+import type { PluginEnvironment } from '../types';
 
 export default async function createPlugin({
   logger,
   config,
   database,
-}: PluginEnvironment) {
+}: PluginEnvironment): Promise<Router> {
   const cookiecutterTemplater = new CookieCutter();
   const craTemplater = new CreateReactAppTemplater();
   const templaters = new Templaters();
diff --git a/packages/create-app/templates/default-app/packages/backend/src/plugins/techdocs.ts b/packages/create-app/templates/default-app/packages/backend/src/plugins/techdocs.ts
index 5c7ec50ae6..0ba08cefaf 100644
--- a/packages/create-app/templates/default-app/packages/backend/src/plugins/techdocs.ts
+++ b/packages/create-app/templates/default-app/packages/backend/src/plugins/techdocs.ts
@@ -1,18 +1,20 @@
 import {
   createRouter,
-  Preparers,
-  Generators,
-  Publisher,
+
+  Generators, Preparers,
+
+  Publisher
 } from '@backstage/plugin-techdocs-backend';
-import { PluginEnvironment } from '../types';
 import Docker from 'dockerode';
+import { Router } from 'express';
+import { PluginEnvironment } from '../types';
 
 export default async function createPlugin({
   logger,
   config,
   discovery,
   reader,
-}: PluginEnvironment) {
+}: PluginEnvironment): Promise<Router> {
   // Preparers are responsible for fetching source files for documentation.
   const preparers = await Preparers.fromConfig(config, {
     logger,
diff --git a/yarn.lock b/yarn.lock
index 818d8d9c9e..deaadc7f25 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -6965,13 +6965,13 @@
   resolved "https://registry.npmjs.org/@types/zen-observable/-/zen-observable-0.8.2.tgz#808c9fa7e4517274ed555fa158f2de4b4f468e71"
   integrity sha512-HrCIVMLjE1MOozVoD86622S7aunluLb2PJdPfb3nYiEtohm8mIB/vyv0Fd37AdeMFrTUQXEunw78YloMA3Qilg==
 
-"@typescript-eslint/eslint-plugin@^v4.14.0":
-  version "4.14.0"
-  resolved "https://registry.npmjs.org/@typescript-eslint/eslint-plugin/-/eslint-plugin-4.14.0.tgz#92db8e7c357ed7d69632d6843ca70b71be3a721d"
-  integrity sha512-IJ5e2W7uFNfg4qh9eHkHRUCbgZ8VKtGwD07kannJvM5t/GU8P8+24NX8gi3Hf5jST5oWPY8kyV1s/WtfiZ4+Ww==
+"@typescript-eslint/eslint-plugin@^v4.15.2":
+  version "4.15.2"
+  resolved "https://registry.npmjs.org/@typescript-eslint/eslint-plugin/-/eslint-plugin-4.15.2.tgz#981b26b4076c62a5a55873fbef3fe98f83360c61"
+  integrity sha512-uiQQeu9tWl3f1+oK0yoAv9lt/KXO24iafxgQTkIYO/kitruILGx3uH+QtIAHqxFV+yIsdnJH+alel9KuE3J15Q==
   dependencies:
-    "@typescript-eslint/experimental-utils" "4.14.0"
-    "@typescript-eslint/scope-manager" "4.14.0"
+    "@typescript-eslint/experimental-utils" "4.15.2"
+    "@typescript-eslint/scope-manager" "4.15.2"
     debug "^4.1.1"
     functional-red-black-tree "^1.0.1"
     lodash "^4.17.15"
@@ -6979,15 +6979,15 @@
     semver "^7.3.2"
     tsutils "^3.17.1"
 
-"@typescript-eslint/experimental-utils@4.14.0", "@typescript-eslint/experimental-utils@^4.0.1":
-  version "4.14.0"
-  resolved "https://registry.npmjs.org/@typescript-eslint/experimental-utils/-/experimental-utils-4.14.0.tgz#5aa7b006736634f588a69ee343ca959cd09988df"
-  integrity sha512-6i6eAoiPlXMKRbXzvoQD5Yn9L7k9ezzGRvzC/x1V3650rUk3c3AOjQyGYyF9BDxQQDK2ElmKOZRD0CbtdkMzQQ==
+"@typescript-eslint/experimental-utils@4.15.2", "@typescript-eslint/experimental-utils@^4.0.1":
+  version "4.15.2"
+  resolved "https://registry.npmjs.org/@typescript-eslint/experimental-utils/-/experimental-utils-4.15.2.tgz#5efd12355bd5b535e1831282e6cf465b9a71cf36"
+  integrity sha512-Fxoshw8+R5X3/Vmqwsjc8nRO/7iTysRtDqx6rlfLZ7HbT8TZhPeQqbPjTyk2RheH3L8afumecTQnUc9EeXxohQ==
   dependencies:
     "@types/json-schema" "^7.0.3"
-    "@typescript-eslint/scope-manager" "4.14.0"
-    "@typescript-eslint/types" "4.14.0"
-    "@typescript-eslint/typescript-estree" "4.14.0"
+    "@typescript-eslint/scope-manager" "4.15.2"
+    "@typescript-eslint/types" "4.15.2"
+    "@typescript-eslint/typescript-estree" "4.15.2"
     eslint-scope "^5.0.0"
     eslint-utils "^2.0.0"
 
@@ -7009,11 +7009,24 @@
     "@typescript-eslint/types" "4.14.0"
     "@typescript-eslint/visitor-keys" "4.14.0"
 
+"@typescript-eslint/scope-manager@4.15.2":
+  version "4.15.2"
+  resolved "https://registry.npmjs.org/@typescript-eslint/scope-manager/-/scope-manager-4.15.2.tgz#5725bda656995960ae1d004bfd1cd70320f37f4f"
+  integrity sha512-Zm0tf/MSKuX6aeJmuXexgdVyxT9/oJJhaCkijv0DvJVT3ui4zY6XYd6iwIo/8GEZGy43cd7w1rFMiCLHbRzAPQ==
+  dependencies:
+    "@typescript-eslint/types" "4.15.2"
+    "@typescript-eslint/visitor-keys" "4.15.2"
+
 "@typescript-eslint/types@4.14.0":
   version "4.14.0"
   resolved "https://registry.npmjs.org/@typescript-eslint/types/-/types-4.14.0.tgz#d8a8202d9b58831d6fd9cee2ba12f8a5a5dd44b6"
   integrity sha512-VsQE4VvpldHrTFuVPY1ZnHn/Txw6cZGjL48e+iBxTi2ksa9DmebKjAeFmTVAYoSkTk7gjA7UqJ7pIsyifTsI4A==
 
+"@typescript-eslint/types@4.15.2":
+  version "4.15.2"
+  resolved "https://registry.npmjs.org/@typescript-eslint/types/-/types-4.15.2.tgz#04acf3a2dc8001a88985291744241e732ef22c60"
+  integrity sha512-r7lW7HFkAarfUylJ2tKndyO9njwSyoy6cpfDKWPX6/ctZA+QyaYscAHXVAfJqtnY6aaTwDYrOhp+ginlbc7HfQ==
+
 "@typescript-eslint/typescript-estree@4.14.0":
   version "4.14.0"
   resolved "https://registry.npmjs.org/@typescript-eslint/typescript-estree/-/typescript-estree-4.14.0.tgz#4bcd67486e9acafc3d0c982b23a9ab8ac8911ed7"
@@ -7028,6 +7041,19 @@
     semver "^7.3.2"
     tsutils "^3.17.1"
 
+"@typescript-eslint/typescript-estree@4.15.2":
+  version "4.15.2"
+  resolved "https://registry.npmjs.org/@typescript-eslint/typescript-estree/-/typescript-estree-4.15.2.tgz#c2f7a1e94f3428d229d5ecff3ead6581ee9b62fa"
+  integrity sha512-cGR8C2g5SPtHTQvAymEODeqx90pJHadWsgTtx6GbnTWKqsg7yp6Eaya9nFzUd4KrKhxdYTTFBiYeTPQaz/l8bw==
+  dependencies:
+    "@typescript-eslint/types" "4.15.2"
+    "@typescript-eslint/visitor-keys" "4.15.2"
+    debug "^4.1.1"
+    globby "^11.0.1"
+    is-glob "^4.0.1"
+    semver "^7.3.2"
+    tsutils "^3.17.1"
+
 "@typescript-eslint/visitor-keys@4.14.0":
   version "4.14.0"
   resolved "https://registry.npmjs.org/@typescript-eslint/visitor-keys/-/visitor-keys-4.14.0.tgz#b1090d9d2955b044b2ea2904a22496849acbdf54"
@@ -7036,6 +7062,14 @@
     "@typescript-eslint/types" "4.14.0"
     eslint-visitor-keys "^2.0.0"
 
+"@typescript-eslint/visitor-keys@4.15.2":
+  version "4.15.2"
+  resolved "https://registry.npmjs.org/@typescript-eslint/visitor-keys/-/visitor-keys-4.15.2.tgz#3d1c7979ce75bf6acf9691109bd0d6b5706192b9"
+  integrity sha512-TME1VgSb7wTwgENN5KVj4Nqg25hP8DisXxNBojM4Nn31rYaNDIocNm5cmjOFfh42n7NVERxWrDFoETO/76ePyg==
+  dependencies:
+    "@typescript-eslint/types" "4.15.2"
+    eslint-visitor-keys "^2.0.0"
+
 "@webassemblyjs/ast@1.9.0":
   version "1.9.0"
   resolved "https://registry.npmjs.org/@webassemblyjs/ast/-/ast-1.9.0.tgz#bd850604b4042459a5a41cd7d338cbed695ed964"