diff --git a/README.md b/README.md
index 698be99..1830e2c 100644
--- a/README.md
+++ b/README.md
@@ -11,7 +11,7 @@
 
 ## Overview
 
-Wrap your own eslint rules in a easy-to-use command line tool and/or a JS module.
+Wrap your own eslint and prettier rules in a easy-to-use command line tool and/or a JS module.
 
 ## Install
 
@@ -61,6 +61,7 @@ require('standard-engine').cli(opts)
 
 ```js
 const eslint = require('eslint')
+const prettier = require('prettier')
 const path = require('path')
 const pkg = require('./package.json')
 
@@ -70,10 +71,14 @@ module.exports = {
   homepage: pkg.homepage,
   bugs: pkg.bugs.url,
   eslint: eslint, // pass any version of eslint >= 1.0.0
+  prettier: prettier, // pass any version of prettier >= 2.0.0
   cmd: 'pocketlint', // should match the "bin" key in your package.json
   tagline: 'Live by your own standards!', // displayed in output --help
   eslintConfig: {
-    configFile: path.join(__dirname, 'eslintrc.json')
+    configFile: path.join(__dirname, '.eslintrc.json')
+  },
+  prettierConfig: {
+    configFile: path.join(__dirname, '.prettierrc.json')
   },
   cwd: '' // current working directory, passed to eslint
 }
@@ -81,9 +86,9 @@ module.exports = {
 
 Additionally an optional `resolveEslintConfig()` function can be provided. See below for details.
 
-### `eslintrc.json`
+### `.eslintrc.json`
 
-Put all your .eslintrc rules in this file. A good practice is to create an  [ESLint Shareable Config](http://eslint.org/docs/developer-guide/shareable-configs) and extend it, but its not required:
+Put all your .eslintrc rules in this file. A good practice is to create an [ESLint Shareable Config](http://eslint.org/docs/developer-guide/shareable-configs) and extend it, but its not required:
 
 ```js
 {
@@ -165,12 +170,7 @@ a `ignore` property to `package.json`:
 Some files are ignored by default:
 
 ```js
-const DEFAULT_IGNORE = [
-  '*.min.js',
-  'coverage/',
-  'node_modules/',
-  'vendor/'
-]
+const DEFAULT_IGNORE = ['*.min.js', 'coverage/', 'node_modules/', 'vendor/']
 ```
 
 You can disable these default ignores by setting the `noDefaultIgnore` option to `true`.
@@ -272,6 +272,7 @@ You can provide a `resolveEslintConfig()` function in the `options.js` exports:
 
 ```js
 const eslint = require('eslint')
+const prettier = require('prettier')
 const path = require('path')
 const pkg = require('./package.json')
 
@@ -281,10 +282,14 @@ module.exports = {
   homepage: pkg.homepage,
   bugs: pkg.bugs.url,
   eslint: eslint, // pass any version of eslint >= 1.0.0
+  prettier: prettier, // pass any version of prettier >= 2.0.0
   cmd: 'pocketlint', // should match the "bin" key in your package.json
   tagline: 'Live by your own standards!', // displayed in output --help
   eslintConfig: {
-    configFile: path.join(__dirname, 'eslintrc.json')
+    configFile: path.join(__dirname, '.eslintrc.json')
+  },
+  prettierConfig: {
+    configFile: path.join(__dirname, '.prettierrc.json')
   },
   resolveEslintConfig: function (eslintConfig, opts, packageOpts, rootDir) {
     // provide implementation here, then return the eslintConfig object (or a new one)
@@ -312,6 +317,7 @@ be provided:
   // common to lintText and lintFiles
   cwd: '',              // current working directory (default: process.cwd())
   fix: false,           // automatically fix problems
+  format: false,        // aggressively format code for consistency
   extensions: [],       // file extensions to lint (has sane defaults)
   globals: [],          // custom global variables to declare
   plugins: [],          // custom eslint plugins
@@ -335,9 +341,7 @@ const results = {
   results: [
     {
       filePath: '',
-      messages: [
-        { ruleId: '', message: '', line: 0, column: 0 }
-      ],
+      messages: [{ ruleId: '', message: '', line: 0, column: 0 }],
       errorCount: 0,
       warningCount: 0,
       output: '' // fixed source code (only present with {fix: true} option)
@@ -365,6 +369,7 @@ Lint the provided `files` globs. An `opts` object may be provided:
   // common to lintText and lintFiles
   cwd: '',              // current working directory (default: process.cwd())
   fix: false,           // automatically fix problems
+  format: false,        // aggressively format code for consistency
   extensions: [],       // file extensions to lint (has sane defaults)
   globals: [],          // custom global variables to declare
   plugins: [],          // custom eslint plugins
@@ -394,6 +399,7 @@ This is the full set of options accepted by the above APIs. Not all options make
   filename: '', // path of the file containing the text being linted (optional)
   fix: false,   // automatically fix problems
   globals: [],  // custom global variables to declare
+  format: false, // aggressively format code for consistency
   plugins: [],  // custom eslint plugins
   envs: [],     // custom eslint environment
   parser: ''    // custom js parser (e.g. babel-eslint)
diff --git a/bin/cmd.js b/bin/cmd.js
index 5f0d4c6..08d8495 100755
--- a/bin/cmd.js
+++ b/bin/cmd.js
@@ -34,6 +34,7 @@ function cli (rawOpts) {
     },
     boolean: [
       'fix',
+      'format',
       'help',
       'stdin',
       'version'
@@ -69,6 +70,7 @@ Usage:
 
 Flags:
         --fix       Automatically fix problems
+        --format    Aggressively format code for consistency
         --version   Show current version
     -h, --help      Show usage information
 
@@ -92,6 +94,7 @@ Flags (advanced):
 
   const lintOpts = {
     fix: argv.fix,
+    format: argv.format,
     extensions: argv.ext,
     globals: argv.global,
     plugins: argv.plugin,
diff --git a/index.js b/index.js
index 14ee6c3..89707f2 100644
--- a/index.js
+++ b/index.js
@@ -1,7 +1,9 @@
 /*! standard-engine. MIT License. Feross Aboukhadijeh <https://feross.org/opensource> */
 
 const os = require('os')
+const fs = require('fs')
 const path = require('path')
+const globby = require('globby')
 
 const CACHE_HOME = require('xdg-basedir').cache || os.tmpdir()
 
@@ -11,12 +13,19 @@ const { resolveEslintConfig } = require('./lib/resolve-eslint-config')
 /** @typedef {Omit<import('./lib/resolve-eslint-config').ResolveOptions, 'cmd'|'cwd'>} BaseLintOptions */
 /** @typedef {(err: Error|unknown, result?: import('eslint').CLIEngine.LintReport) => void} LinterCallback */
 
+/**
+ * @typedef PrettierOptions
+ * @property {string | null} [configFile]
+ */
+
 /**
  * @typedef LinterOptions
  * @property {string} cmd
  * @property {import('eslint')} eslint
+ * @property {import('prettier')} prettier
  * @property {string} [cwd]
  * @property {CLIEngineOptions} [eslintConfig]
+ * @property {PrettierOptions} [prettierConfig]
  * @property {import('./lib/resolve-eslint-config').CustomEslintConfigResolver} [resolveEslintConfig]
  * @property {string} [version]
  */
@@ -28,11 +37,14 @@ class Linter {
   constructor (opts) {
     if (!opts || !opts.cmd) throw new Error('opts.cmd option is required')
     if (!opts.eslint) throw new Error('opts.eslint option is required')
+    if (!opts.prettier) throw new Error('opts.prettier option is required')
 
     /** @type {string} */
     this.cmd = opts.cmd
     /** @type {import('eslint')} */
     this.eslint = opts.eslint
+    /** @type {import('prettier')} */
+    this.prettier = opts.prettier
     /** @type {string} */
     this.cwd = opts.cwd || process.cwd()
     this.customEslintConfigResolver = opts.resolveEslintConfig
@@ -57,6 +69,11 @@ class Linter {
       ...(opts.eslintConfig || {})
     }
 
+    /** @type {PrettierOptions} */
+    this.prettierConfig = {
+      configFile: opts.prettierConfig != null ? opts.prettierConfig.configFile : null
+    }
+
     if (this.eslintConfig.configFile != null) {
       this.eslintConfig.resolvePluginsRelativeTo = path.dirname(
         this.eslintConfig.configFile
@@ -102,19 +119,54 @@ class Linter {
    * Lint files to enforce JavaScript Style.
    *
    * @param {Array.<string>} files          file globs to lint
-   * @param {BaseLintOptions & { cwd?: string }} [opts] base options + file globs to ignore (has sane defaults) + current working directory (default: process.cwd())
+   * @param {BaseLintOptions & { cwd?: string, format?: boolean }} [opts] base options + file globs to ignore (has sane defaults) + current working directory (default: process.cwd())
    * @param {LinterCallback} [cb]
    * @returns {void}
    */
   lintFiles (files, opts, cb) {
     if (typeof opts === 'function') { return this.lintFiles(files, undefined, opts) }
     if (!cb) throw new Error('callback is required')
+    const format = opts == null ? false : opts.format
 
     const eslintConfig = this.resolveEslintConfig(opts)
 
     if (typeof files === 'string') files = [files]
     if (files.length === 0) files = ['.']
 
+    if (format) {
+      /** @type {string[]} */
+      const extensionsArray = []
+      this.prettier.getSupportInfo().languages.forEach((language) => {
+        if (language != null && language.extensions != null) {
+          extensionsArray.push(...language.extensions)
+        }
+      })
+      const extensions = extensionsArray.join(',')
+      const prettierOptions = this.prettier.resolveConfig.sync(
+        this.prettierConfig.configFile == null ? path.join(__dirname, '.prettierrc.json') : this.prettierConfig.configFile
+      ) || {}
+      const ignore = typeof eslintConfig.ignorePattern === 'string'
+        ? [eslintConfig.ignorePattern]
+        : eslintConfig.ignorePattern == null
+          ? []
+          : eslintConfig.ignorePattern
+      const files = globby.sync([`**/*{${extensions}}`], {
+        ignore,
+        cwd: opts == null ? undefined : opts.cwd
+      })
+      for (const file of files) {
+        const filePath = path.join(process.cwd(), file)
+        const fileInfo = this.prettier.getFileInfo.sync(filePath, {})
+        prettierOptions.parser = fileInfo.inferredParser == null ? 'babel' : fileInfo.inferredParser
+        const input = fs.readFileSync(filePath, 'utf8')
+        const output = this.prettier.format(input, prettierOptions)
+        const formatted = input !== output
+        if (formatted) {
+          fs.writeFileSync(filePath, output, { encoding: 'utf8' })
+        }
+      }
+    }
+
     let result
     try {
       result = new this.eslint.CLIEngine(eslintConfig).executeOnFiles(files)
@@ -122,7 +174,7 @@ class Linter {
       return cb(err)
     }
 
-    if (eslintConfig.fix) {
+    if (eslintConfig.fix || format) {
       this.eslint.CLIEngine.outputFixes(result)
     }
 
diff --git a/package.json b/package.json
index 3d0e73c..2c78ac6 100644
--- a/package.json
+++ b/package.json
@@ -39,6 +39,7 @@
   },
   "dependencies": {
     "get-stdin": "^8.0.0",
+    "globby": "^11.0.4",
     "minimist": "^1.2.5",
     "pkg-conf": "^3.1.0",
     "xdg-basedir": "^4.0.0"
@@ -48,6 +49,7 @@
     "@types/eslint": "^7.28.0",
     "@types/minimist": "^1.2.2",
     "@types/node": "~12.20.0",
+    "@types/prettier": "^2.3.2",
     "cross-spawn": "^7.0.3",
     "eslint": "^7.12.1",
     "eslint-config-standard": "^16.0.0",
@@ -56,6 +58,7 @@
     "eslint-plugin-node": "^11.1.0",
     "eslint-plugin-promise": "^5.1.0",
     "eslint-plugin-react": "^7.21.5",
+    "prettier": "^2.4.0",
     "standard": "*",
     "tape": "^5.0.1",
     "typescript": "~4.4.3"
diff --git a/test/api.js b/test/api.js
index dd51d2b..9e5e084 100644
--- a/test/api.js
+++ b/test/api.js
@@ -1,4 +1,5 @@
 const eslint = require('eslint')
+const prettier = require('prettier')
 const path = require('path')
 const test = require('tape')
 
@@ -9,6 +10,7 @@ function getStandard () {
     cmd: 'pocketlint',
     version: '0.0.0',
     eslint,
+    prettier,
     eslintConfig: require('../tmp/standard/options').eslintConfig
   })
 }
diff --git a/test/lib/standard-cmd.js b/test/lib/standard-cmd.js
index 2f898f9..f7f144e 100755
--- a/test/lib/standard-cmd.js
+++ b/test/lib/standard-cmd.js
@@ -1,11 +1,13 @@
 #!/usr/bin/env node
 const path = require('path')
 const eslint = require('eslint')
+const prettier = require('prettier')
 
 const opts = {
   cmd: 'pocketlint',
   version: '0.0.0',
   eslint,
+  prettier,
   eslintConfig: {
     configFile: path.join(__dirname, 'standard.json'),
     useEslintrc: false