diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8d0e26ad..b3706f43 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,10 @@
+# master
+Add a pretty print option to `toString(false)`
+pass true pretty print
+
 # 4.0.2
 Fix npx script error - needs the shebang
+
 # 4.0.1
 Validation functions which depend on xmllint will now warn if you do not have xmllint installed.
 
diff --git a/README.md b/README.md
index ccff793a..05dc65d4 100644
--- a/README.md
+++ b/README.md
@@ -16,22 +16,22 @@ Table of Contents
 
   * [Installation](#installation)
   * [Usage](#usage)
-    * [CLI](#CLI)
+    * [CLI](#cli)
     * [Example of using sitemap.js with <a href="https://expressjs.com/">express</a>:](#example-of-using-sitemapjs-with-express)
     * [Example of dynamic page manipulations into sitemap:](#example-of-dynamic-page-manipulations-into-sitemap)
     * [Example of most of the options you can use for sitemap](#example-of-most-of-the-options-you-can-use-for-sitemap)
     * [Building just the sitemap index file](#building-just-the-sitemap-index-file)
     * [Auto creating sitemap and index files from one large list](#auto-creating-sitemap-and-index-files-from-one-large-list)
-  * [API](#API)
+  * [API](#api)
     * [Create Sitemap](#create-sitemap)
     * [Sitemap](#sitemap)
     * [buildSitemapIndex](#buildsitemapindex)
     * [createSitemapIndex](#createsitemapindex)
     * [Sitemap Item Options](#sitemap-item-options)
-    * [ISitemapImage](#ISitemapImage)
-    * [IVideoItem](#IVideoItem)
-    * [ILinkItem](#ILinkItem)
-    * [INewsItem](#INewsItem)
+    * [ISitemapImage](#isitemapimage)
+    * [IVideoItem](#ivideoitem)
+    * [ILinkItem](#ilinkitem)
+    * [INewsItem](#inewsitem)
   * [License](#license)
 
 Installation
@@ -58,8 +58,6 @@ Or verify an existing sitemap
 
 ## As a library
 
-The main functions you want to use in the sitemap module are
-
 ```javascript
 const { createSitemap } = require('sitemap')
 // Creates a sitemap object given the input configuration with URLs
@@ -222,11 +220,11 @@ const smi = createSitemapIndex({
 ## API 
 
 
-## Sitemap
+### Sitemap
 
 ```
 const { Sitemap } = require('sitemap')
-const sm = new Sitemap({
+const smi = new Sitemap({
     urls: [{url: '/path'}],
     hostname: 'http://example.com',
     cacheTime: 0, // default
@@ -234,8 +232,75 @@ const sm = new Sitemap({
 })
 sm.toString() // returns the xml as a string
 ```
-
-## buildSitemapIndex
+  
+__toString__
+  ```
+  smi.toString(true)
+  ```
+  Converts the urls stored in an instance of Sitemap to a valid sitemap xml document as a string. Accepts a boolean as its first argument to designate on whether to pretty print. Defaults to false.
+  
+__toXML__
+alias for toString
+
+__toGzip__
+  ```
+  smi.toGzip ((xmlGzippedBuffer) => console.log(xmlGzippedBuffer));
+  smi.toGzip();
+  ```
+  like toString, it builds the xmlDocument, then it runs gzip on the resulting string and returns it as a Buffer via callback or direct invokation
+  
+__clearCache__
+  ```
+  smi.clearCache()
+  ```
+  cache will be emptied and will be bipassed until set again
+  
+__isCacheValid__
+  ```
+  smi.isCacheValid()
+  ```
+  returns true if it has been less than cacheTimeout ms since cache was set
+  
+__setCache__
+  ```
+  smi.setCache('...xmlDoc')
+  ```
+  stores the passed in string on the instance to be used when toString is called within the configured cacheTimeout
+  returns the passed in string unaltered
+  
+__add__
+  ```
+  smi.add('/path', 'warn')
+  ```
+  adds the provided url to the sitemap instance
+  takes an optional parameter level for whether to print a console warning in the event of bad data 'warn' (default), throw an exception 'throw', or quietly ignore bad data 'silent'
+  returns the number of locations currently in the sitemap instance
+  
+__contains__
+  ```
+  smi.contains('/path')
+  ```
+  Returns true if path is already a part of the sitemap instance, false otherwise. 
+  
+__del__
+  ```
+  smi.del('/path')
+  ```
+  removes the provided url or url option from the sitemap instance
+
+__normalizeURL__
+  ```
+  Sitemap.normalizeURL('/', undefined, 'http://example.com')
+  ```
+  static function that returns the stricter form of a options passed to SitemapItem
+  
+__normalizeURLs__
+  ```
+  Sitemap.normalizeURLs(['http://example.com', {url: 'http://example.com'}])
+  ```
+  static function that takes an array of urls and returns a Map of their resolved url to the strict form of SitemapItemOptions
+
+### buildSitemapIndex
 Build a sitemap index file
 ```
 const { buildSitemapIndex } = require('sitemap')
@@ -245,7 +310,7 @@ const index =   buildSitemapIndex({
 })
 ```
 
-## createSitemapIndex
+### createSitemapIndex
 Create several sitemaps and an index automatically from a list of urls
 ```
 const { createSitemapIndex } = require('sitemap')
@@ -262,7 +327,7 @@ createSitemapIndex({
 })
 ```
 
-## Sitemap Item Options
+### Sitemap Item Options
 
 |Option|Type|eg|Description|
 |------|----|--|-----------|
@@ -278,7 +343,7 @@ createSitemapIndex({
 |mobile|boolean or string|||
 |cdata|boolean|true|wrap url in cdata xml escape|
 
-## ISitemapImage
+### ISitemapImage
 
 Sitemap image
 https://support.google.com/webmasters/answer/178636?hl=en&ref_topic=4581190
@@ -291,7 +356,7 @@ https://support.google.com/webmasters/answer/178636?hl=en&ref_topic=4581190
 |geoLocation|string - optional|'Limerick, Ireland'|The geographic location of the image.|
 |license|string - optional|'http://example.com/license.txt'|A URL to the license of the image.|
 
-## IVideoItem
+### IVideoItem
 
 Sitemap video. https://support.google.com/webmasters/answer/80471?hl=en&ref_topic=4581190
 
@@ -326,7 +391,7 @@ Sitemap video. https://support.google.com/webmasters/answer/80471?hl=en&ref_topi
 |requires_subscription|string 'YES'\|'NO' - optional|'YES'|Indicates whether a subscription (either paid or free) is required to view the video. Allowed values are yes or no.|
 |live|string 'YES'\|'NO' - optional|'NO'|Indicates whether the video is a live stream. Supported values are yes or no.|
 
-## ILinkItem
+### ILinkItem
 
 https://support.google.com/webmasters/answer/189077
 
@@ -335,7 +400,7 @@ https://support.google.com/webmasters/answer/189077
 |lang|string|'en'||
 |url|string|'http://example.com/en/'||
 
-## INewsItem
+### INewsItem
 
 https://support.google.com/webmasters/answer/74288?hl=en&ref_topic=4581190
 
diff --git a/lib/sitemap.ts b/lib/sitemap.ts
index 9953fc80..1dfa6baf 100644
--- a/lib/sitemap.ts
+++ b/lib/sitemap.ts
@@ -299,7 +299,7 @@ export class Sitemap {
    *  Synchronous alias for toXML()
    *  @return {String}
    */
-  toString (): string {
+  toString (pretty = false): string {
     if (this.root.children.length) {
       this.root.children = []
     }
@@ -325,8 +325,11 @@ export class Sitemap {
     for (let [, smi] of this.urls) {
       (new SitemapItem(smi, this.root)).buildXML()
     }
-
-    return this.setCache(this.root.end())
+    let opts
+    if (pretty) {
+      opts = {pretty}
+    }
+    return this.setCache(this.root.end(opts))
   }
 
   toGzip (callback: CompressCallback): void;
diff --git a/package-lock.json b/package-lock.json
index 29f1da05..2ffbd2ed 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "sitemap",
-  "version": "3.2.2",
+  "version": "4.0.2",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
diff --git a/tests/sitemap.test.ts b/tests/sitemap.test.ts
index d60ac71c..e4c620c0 100644
--- a/tests/sitemap.test.ts
+++ b/tests/sitemap.test.ts
@@ -51,6 +51,17 @@ describe('sitemap', () => {
               '</urlset>')
   })
 
+  it('pretty prints', () => {
+    var ssp = new Sitemap({urls: ['http://ya.ru']})
+    expect(ssp.toString(true)).toBe(
+      xmlDef + '\n' +
+                urlset + '\n' +
+                '  <url>\n    ' +
+                    xmlLoc + '\n' +
+                '  </url>\n' +
+              '</urlset>')
+  })
+
   describe('normalizeURL', () => {
     it('turns strings into full urls', () => {
       expect(Sitemap.normalizeURL('http://example.com', create('urlset'))).toHaveProperty('url', 'http://example.com/')