diff --git a/packages/cli/package.json b/packages/cli/package.json
index bc1a349aa3..418e5f9fe2 100644
--- a/packages/cli/package.json
+++ b/packages/cli/package.json
@@ -29,6 +29,7 @@
     "backstage-cli": "bin/backstage-cli"
   },
   "devDependencies": {
+    "@types/diff": "^4.0.2",
     "@types/fs-extra": "^8.1.0",
     "@types/html-webpack-plugin": "^3.2.2",
     "@types/inquirer": "^6.5.0",
@@ -58,6 +59,7 @@
     "chokidar": "^3.3.1",
     "commander": "^4.1.1",
     "dashify": "^2.0.0",
+    "diff": "^4.0.2",
     "eslint-plugin-import": "^2.20.2",
     "eslint-plugin-monorepo": "^0.2.1",
     "fork-ts-checker-webpack-plugin": "^4.0.5",
diff --git a/packages/cli/src/commands/plugin/diff/handlers.ts b/packages/cli/src/commands/plugin/diff/handlers.ts
new file mode 100644
index 0000000000..df7ca081de
--- /dev/null
+++ b/packages/cli/src/commands/plugin/diff/handlers.ts
@@ -0,0 +1,209 @@
+/*
+ * 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 fs from 'fs-extra';
+import chalk from 'chalk';
+import { dirname } from 'path';
+import { diffLines } from 'diff';
+import { paths } from 'lib/paths';
+import { TemplateFile, PromptFunc, FileHandler } from './types';
+
+export async function writeTargetFile(targetPath: string, contents: string) {
+  const path = paths.resolveTarget(targetPath);
+  await fs.ensureDir(dirname(path));
+  await fs.writeFile(path, contents, 'utf8');
+}
+
+class PackageJsonHandler {
+  static async handler(file: TemplateFile, prompt: PromptFunc) {
+    console.log('Checking package.json');
+
+    if (!file.targetExists) {
+      throw new Error(`${file.targetPath} doesn't exist`);
+    }
+
+    const pkg = JSON.parse(file.templateContents);
+    const targetPkg = JSON.parse(file.targetContents);
+
+    const handler = new PackageJsonHandler(file, prompt, pkg, targetPkg);
+    await handler.handle();
+  }
+
+  constructor(
+    private readonly file: TemplateFile,
+    private readonly prompt: PromptFunc,
+    private readonly pkg: any,
+    private readonly targetPkg: any,
+  ) {}
+
+  async handle() {
+    await this.syncField('main');
+    await this.syncField('types');
+    await this.syncField('files');
+    await this.syncScripts();
+    await this.syncDependencies('dependencies');
+    await this.syncDependencies('devDependencies');
+  }
+
+  // Make sure a field inside package.json is in sync. This mutates the targetObj and writes package.json on change.
+  private async syncField(
+    fieldName: string,
+    obj: any = this.pkg,
+    targetObj: any = this.targetPkg,
+    prefix?: string,
+  ) {
+    const fullFieldName = chalk.cyan(
+      prefix ? `${prefix}[${fieldName}]` : fieldName,
+    );
+    const newValue = obj[fieldName];
+    const coloredNewValue = chalk.cyan(JSON.stringify(newValue));
+
+    if (fieldName in targetObj) {
+      const oldValue = targetObj[fieldName];
+      if (JSON.stringify(oldValue) === JSON.stringify(newValue)) {
+        return;
+      }
+
+      const coloredOldValue = chalk.cyan(JSON.stringify(oldValue));
+      const msg = `package.json has mismatched field, ${fullFieldName}, change from ${coloredOldValue} to ${coloredNewValue}?`;
+      if (await this.prompt(msg)) {
+        targetObj[fieldName] = newValue;
+        await this.write();
+      }
+    } else {
+      if (
+        await this.prompt(
+          `package.json is missing field ${fullFieldName}, set to ${coloredNewValue}?`,
+        )
+      ) {
+        targetObj[fieldName] = newValue;
+        await this.write();
+      }
+    }
+  }
+
+  private async syncScripts() {
+    const pkgScripts = this.pkg.scripts;
+    const targetScripts = (this.targetPkg.scripts =
+      this.targetPkg.scripts || {});
+
+    for (const key of Object.keys(pkgScripts)) {
+      await this.syncField(key, pkgScripts, targetScripts, 'scripts');
+    }
+  }
+
+  private async syncDependencies(fieldName: string) {
+    const pkgDeps = this.pkg[fieldName];
+    const targetDeps = (this.targetPkg[fieldName] =
+      this.targetPkg[fieldName] || {});
+
+    for (const key of Object.keys(pkgDeps)) {
+      await this.syncField(key, pkgDeps, targetDeps, fieldName);
+    }
+  }
+
+  private async write() {
+    await fs.writeFile(
+      paths.resolveTarget(this.file.targetPath),
+      `${JSON.stringify(this.targetPkg, null, 2)}\n`,
+    );
+  }
+}
+
+// Make sure the file is an exact match of the template
+async function exactMatchHandler(file: TemplateFile, prompt: PromptFunc) {
+  console.log(`Checking ${file.targetPath}`);
+
+  const { targetPath, templateContents } = file;
+  const coloredPath = chalk.cyan(targetPath);
+
+  if (!file.targetExists) {
+    if (await prompt(`Missing ${coloredPath}, do you want to add it?`)) {
+      await writeTargetFile(targetPath, templateContents);
+    }
+    return;
+  }
+  if (file.targetContents === templateContents) {
+    return;
+  }
+
+  const diffs = diffLines(file.targetContents, templateContents);
+  for (const diff of diffs) {
+    if (diff.added) {
+      process.stdout.write(chalk.green(`+${diff.value}`));
+    } else if (diff.removed) {
+      process.stdout.write(chalk.red(`-${diff.value}`));
+    } else {
+      process.stdout.write(` ${diff.value}`);
+    }
+  }
+
+  if (
+    await prompt(
+      `Outdated ${coloredPath}, do you want to apply the above patch?`,
+    )
+  ) {
+    await writeTargetFile(targetPath, templateContents);
+  }
+}
+
+// Adds the file if it is missing, but doesn't check existing files
+async function existsHandler(file: TemplateFile, prompt: PromptFunc) {
+  console.log(`Making sure ${file.targetPath} exists`);
+
+  const { targetPath, templateContents } = file;
+  const coloredPath = chalk.cyan(targetPath);
+
+  if (!file.targetExists) {
+    if (await prompt(`Missing ${coloredPath}, do you want to add it?`)) {
+      await writeTargetFile(targetPath, templateContents);
+    }
+    return;
+  }
+}
+
+async function skipHandler(file: TemplateFile) {
+  console.log(`Skipping ${file.targetPath}`);
+}
+
+export const handlers = {
+  skip: skipHandler,
+  exists: existsHandler,
+  exactMatch: exactMatchHandler,
+  packageJson: PackageJsonHandler.handler,
+};
+
+export async function handleAllFiles(
+  fileHandlers: FileHandler[],
+  files: TemplateFile[],
+  promptFunc: PromptFunc,
+) {
+  for (const file of files) {
+    const { targetPath } = file;
+    const fileHandler = fileHandlers.find(handler =>
+      handler.patterns.some(pattern =>
+        typeof pattern === 'string'
+          ? pattern === targetPath
+          : pattern.test(targetPath),
+      ),
+    );
+    if (fileHandler) {
+      await fileHandler.handler(file, promptFunc);
+    } else {
+      throw new Error(`No template file handler found for ${targetPath}`);
+    }
+  }
+}
diff --git a/packages/cli/src/commands/plugin/diff/index.ts b/packages/cli/src/commands/plugin/diff/index.ts
new file mode 100644
index 0000000000..116ba9e633
--- /dev/null
+++ b/packages/cli/src/commands/plugin/diff/index.ts
@@ -0,0 +1,72 @@
+/*
+ * Copyright 2020 Spotify AB
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import chalk from 'chalk';
+import inquirer from 'inquirer';
+import { Command } from 'commander';
+import { readTemplateFiles } from './read';
+import { handlers, handleAllFiles } from './handlers';
+import { PromptFunc } from './types';
+
+const fileHandlers = [
+  {
+    patterns: ['package.json'],
+    handler: handlers.packageJson,
+  },
+  {
+    patterns: ['tsconfig.json'],
+    handler: handlers.exactMatch,
+  },
+  {
+    // make sure files in 1st level of src/ and dev/ exist
+    patterns: ['.eslintrc.js', /^(src|dev)\/[^/]+$/],
+    handler: handlers.exists,
+  },
+  {
+    patterns: ['README.md', /^src\//],
+    handler: handlers.skip,
+  },
+];
+
+const inquirerPromptFunc: PromptFunc = async msg => {
+  const { result } = await inquirer.prompt({
+    type: 'confirm',
+    name: 'result',
+    message: chalk.blue(msg),
+  });
+  return result;
+};
+
+const checkPromptFunc: PromptFunc = async msg => {
+  throw new Error(`Check failed, the following change was needed: ${msg}`);
+};
+const yesPromptFunc: PromptFunc = async msg => {
+  console.log(`Accepting: "${msg}"`);
+  return true;
+};
+
+export default async (cmd: Command) => {
+  let promptFunc = inquirerPromptFunc;
+
+  if (cmd.check) {
+    promptFunc = checkPromptFunc;
+  } else if (cmd.yes) {
+    promptFunc = yesPromptFunc;
+  }
+
+  const templateFiles = await readTemplateFiles('default-plugin');
+  await handleAllFiles(fileHandlers, templateFiles, promptFunc);
+};
diff --git a/packages/cli/src/commands/plugin/diff/read.ts b/packages/cli/src/commands/plugin/diff/read.ts
new file mode 100644
index 0000000000..ef981a0081
--- /dev/null
+++ b/packages/cli/src/commands/plugin/diff/read.ts
@@ -0,0 +1,110 @@
+/*
+ * 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 fs from 'fs-extra';
+import { relative as relativePath } from 'path';
+import handlebars from 'handlebars';
+import recursiveReadDir from 'recursive-readdir';
+import { paths } from 'lib/paths';
+import { version } from 'lib/version';
+import { PluginInfo, TemplateFile } from './types';
+
+// Reads info from the existing plugin
+export async function readPluginInfo(): Promise<PluginInfo> {
+  let name: string;
+  try {
+    const pkg = require(paths.resolveTarget('package.json'));
+    name = pkg.name;
+  } catch (error) {
+    throw new Error(`Failed to read target package, ${error}`);
+  }
+
+  const pluginTsContents = await fs.readFile(
+    paths.resolveTarget('src/plugin.ts'),
+    'utf8',
+  );
+  // TODO: replace with some proper parsing logic or plugin metadata file
+  const pluginIdMatch = pluginTsContents.match(/id: ['"`](.+?)['"`]/);
+  if (!pluginIdMatch) {
+    throw new Error(`Failed to parse plugin.ts, no plugin ID found`);
+  }
+
+  const id = pluginIdMatch[1];
+
+  return { id, name };
+}
+
+export async function readTemplateFile(
+  templateFile: string,
+  templateVars: any,
+): Promise<string> {
+  const contents = await fs.readFile(templateFile, 'utf8');
+
+  if (!templateFile.endsWith('.hbs')) {
+    return contents;
+  }
+
+  return handlebars.compile(contents)(templateVars);
+}
+
+export async function readTemplate(
+  templateDir: string,
+  templateVars: any,
+): Promise<TemplateFile[]> {
+  const templateFilePaths = await recursiveReadDir(templateDir).catch(error => {
+    throw new Error(`Failed to read template directory: ${error.message}`);
+  });
+
+  const templateFiles = new Array<TemplateFile>();
+  for (const templateFile of templateFilePaths) {
+    // Target file inside the target dir without template extension
+    const targetFile = templateFile
+      .replace(templateDir, paths.targetDir)
+      .replace(/\.hbs$/, '');
+    const targetPath = relativePath(paths.targetDir, targetFile);
+
+    const templateContents = await readTemplateFile(templateFile, templateVars);
+
+    const targetExists = await fs.pathExists(targetFile);
+    if (targetExists) {
+      const targetContents = await fs.readFile(targetFile, 'utf8');
+      templateFiles.push({
+        targetPath,
+        targetExists,
+        targetContents,
+        templateContents,
+      });
+    } else {
+      templateFiles.push({
+        targetPath,
+        targetExists,
+        templateContents,
+      });
+    }
+  }
+
+  return templateFiles;
+}
+
+// Read all template files for a given template, along with all matching files in the target dir
+export async function readTemplateFiles(template: string) {
+  const pluginInfo = await readPluginInfo();
+  const templateVars = { version, ...pluginInfo };
+
+  const templateDir = paths.resolveOwn('templates', template);
+
+  return await readTemplate(templateDir, templateVars);
+}
diff --git a/packages/cli/src/commands/plugin/diff/types.ts b/packages/cli/src/commands/plugin/diff/types.ts
new file mode 100644
index 0000000000..7a04cf8d2e
--- /dev/null
+++ b/packages/cli/src/commands/plugin/diff/types.ts
@@ -0,0 +1,50 @@
+/*
+ * 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.
+ */
+
+export type PluginInfo = {
+  id: string;
+  name: string;
+};
+
+export type TemplateFile = {
+  // Relative path within the target directory
+  targetPath: string;
+  // Contents of the compiled template file
+  templateContents: string;
+} & (
+  | {
+      // Whether the template file exists in the target directory
+      targetExists: true;
+      // Contents of the file in the target directory, if it exists
+      targetContents: string;
+    }
+  | {
+      // Whether the template file exists in the target directory
+      targetExists: false;
+    }
+);
+
+export type PromptFunc = (msg: string) => Promise<boolean>;
+
+export type HandlerFunc = (
+  file: TemplateFile,
+  prompt: PromptFunc,
+) => Promise<void>;
+
+export type FileHandler = {
+  patterns: Array<string | RegExp>;
+  handler: HandlerFunc;
+};
diff --git a/packages/cli/src/index.ts b/packages/cli/src/index.ts
index 1c3f66bce7..6c6aec3776 100644
--- a/packages/cli/src/index.ts
+++ b/packages/cli/src/index.ts
@@ -62,6 +62,13 @@ const main = (argv: string[]) => {
     .description('Serves the dev/ folder of a plugin')
     .action(actionHandler(() => require('commands/plugin/serve')));
 
+  program
+    .command('plugin:diff')
+    .option('--check', 'Fail if changes are required')
+    .option('--yes', 'Apply all changes')
+    .description('Diff an existing plugin with the creation template')
+    .action(actionHandler(() => require('commands/plugin/diff')));
+
   program
     .command('lint')
     .option('--fix', 'Attempt to automatically fix violations')
diff --git a/yarn.lock b/yarn.lock
index fd89c86b9f..ab56118174 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -3947,6 +3947,11 @@
   resolved "https://registry.npmjs.org/@types/debug/-/debug-4.1.5.tgz#b14efa8852b7768d898906613c23f688713e02cd"
   integrity sha512-Q1y515GcOdTHgagaVFhHnIFQ38ygs/kmxdNpvpou+raI9UO3YZcHDngBSYKQklcKlvA7iuQlmIKbzvmxcOE9CQ==
 
+"@types/diff@^4.0.2":
+  version "4.0.2"
+  resolved "https://registry.npmjs.org/@types/diff/-/diff-4.0.2.tgz#2e9bb89f9acc3ab0108f0f3dc4dbdcf2fff8a99c"
+  integrity sha512-mIenTfsIe586/yzsyfql69KRnA75S8SVXQbTLpDejRrjH0QSJcpu3AUOi/Vjnt9IOsXKxPhJfGpQUNMueIU1fQ==
+
 "@types/eslint-visitor-keys@^1.0.0":
   version "1.0.0"
   resolved "https://registry.npmjs.org/@types/eslint-visitor-keys/-/eslint-visitor-keys-1.0.0.tgz#1ee30d79544ca84d68d4b3cdb0af4f205663dd2d"
@@ -8187,7 +8192,7 @@ diff-sequences@^25.1.0:
   resolved "https://registry.npmjs.org/diff-sequences/-/diff-sequences-25.1.0.tgz#fd29a46f1c913fd66c22645dc75bffbe43051f32"
   integrity sha512-nFIfVk5B/NStCsJ+zaPO4vYuLjlzQ6uFvPxzYyHlejNZ/UGa7G/n7peOXVrVNvRuyfstt+mZQYGpjxg9Z6N8Kw==
 
-diff@^4.0.1:
+diff@^4.0.1, diff@^4.0.2:
   version "4.0.2"
   resolved "https://registry.npmjs.org/diff/-/diff-4.0.2.tgz#60f3aecb89d5fae520c11aa19efc2bb982aade7d"
   integrity sha512-58lmxKSA4BNyLz+HHMUzlOEpg09FV+ev6ZMe3vJihgdxzgcwZ8VoEEPmALCZG9LmqfVoNMMKpttIYTVG6uDY7A==