diff --git a/.gitignore b/.gitignore
index 8b7ef35..e22ebed 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,3 @@
 /vendor
 composer.lock
+.DS_Store
\ No newline at end of file
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 727cb1b..4138996 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,24 @@
 # Changelog
 
+## v0.4.0
+* Make api key optional when initializing client.
+* Etsy::getUser now supports an optional user ID.
+* Add expiry value to access tokens.
+* Change Listing update request to use new PATCH method.
+* Add new associations to Listing resource.
+* Update endpoints for various Listing associated resources.
+
+### New
+* Added Etsy::getMe() method: [User getMe method](https://developers.etsy.com/documentation/reference#operation/getMe)
+* Added Etsy::tokenScopes method: [tokenScopes](https://developers.etsy.com/documentation/reference#operation/tokenScopes)
+* Added new [BuyerTaxonomy](https://developers.etsy.com/documentation/reference#tag/BuyerTaxonomy) and BuyerTaxonomyProperty resource and supporting methods.
+* Added Etsy::findShops() method: [findShops](https://developers.etsy.com/documentation/reference#operation/findShops)
+* Add new [ListingVideo](https://developers.etsy.com/documentation/reference#tag/ShopListing-Video) resource and supporting methods.
+* Add new [ProductionPartner](https://developers.etsy.com/documentation/reference#tag/Shop-ProductionPartner) resource and supporting methods.
+* Add new [ReturnPolicy](https://developers.etsy.com/documentation/reference#tag/Shop-Return-Policy) resource and supporting methods.
+
+---
+
 ## v0.3.4
 ### Fixed issues
 * Add pagination support for the Receipt resource. [Issue #15](https://github.com/rhysnhall/etsy-php-sdk/issues/15)
diff --git a/composer.json b/composer.json
index 2964881..eed1a65 100644
--- a/composer.json
+++ b/composer.json
@@ -1,6 +1,6 @@
 {
   "name": "rhysnhall/etsy-php-sdk",
-  "version": "0.3.4",
+  "version": "0.4.0",
   "description": "PHP SDK for Etsy API v3.",
   "type": "library",
   "keywords": [
@@ -15,6 +15,11 @@
       "name": "Rhys Hall",
       "email": "hello@rhyshall.com",
       "homepage": "https://github.com/rhysnhall"
+    },
+    {
+      "name": "Andrew Christensen",
+      "email": "andrew@critical-code.com",
+      "homepage": "https://github.com/erankco"
     }
   ],
   "require": {
diff --git a/src/Etsy.php b/src/Etsy.php
index d97bbbd..b34228d 100644
--- a/src/Etsy.php
+++ b/src/Etsy.php
@@ -29,7 +29,7 @@ class Etsy {
 
   public function __construct(
     string $client_id,
-    string $api_key,
+    string $api_key = null,
     array $config = []
   ) {
     $this->client_id = $client_id;
@@ -118,16 +118,38 @@ public function ping() {
   }
 
   /**
-   * Only supports getting the user for who the current API KEY is associated with.
+   * Gets the user id and shop id for the logged in user.
+   * 
+   * @return array
+   */
+  public function getMe() {
+    $response = static::$client->get("/application/users/me");
+    return $response ?? [];
+  }
+
+  /**
+   * Gets the scopes for the current token
+   * 
+   * @return array
+   */
+  public function tokenScopes() {
+    $response = static::$client->post("/application/scopes");
+    return $response ?? [];
+  }
+
+  /**
+   * Get the user for the current tokened user or for a specified user.
    *
+   * @params int|null $user_id
    * @return Etsy\Resources\User
    */
-  public function getUser() {
-    $user_id = explode(".", $this->api_key)[0];
-    $response = static::$client->get("/application/users/{$user_id}");
+  public function getUser($user_id = null) {
+    $user_id = $user_id ?? explode(".", $this->api_key)[0];
+    $response = static::$client->get("/application/users/{$user_id}", []);
     return static::getResource($response, "User");
   }
 
+
   /**
    * Gets an Etsy shop. If no shop_id is specified the current user will be queried for an associated shop.
    *
@@ -166,6 +188,7 @@ public function getShops($keyword, $params = []) {
   /**
    * Retrieves the full hierarchy tree of seller taxonomy nodes.
    *
+   * @link https://developers.etsy.com/documentation/reference#tag/getSellerTaxonomyNodes
    * @return Etsy\Collection[Etsy\Resources\Taxonomy]
    */
   public function getSellerTaxonomy() {
@@ -175,6 +198,19 @@ public function getSellerTaxonomy() {
     return static::getResource($response, "Taxonomy");
   }
 
+  /**
+   * Retrieves the full hierarchy tree of buyer taxonomy nodes.
+   *
+   * @link https://developers.etsy.com/documentation/reference#operation/getBuyerTaxonomyNodes
+   * @return Etsy\Collection[Etsy\Resources\BuyerTaxonomy]
+   */
+  public function getBuyerTaxonomy() {
+    $response = static::$client->get(
+      "/application/buyer-taxonomy/nodes"
+    );
+    return static::getResource($response, "BuyerTaxonomy");
+  }
+
   /**
    * Retrieves a list of available shipping carriers and the mail classes associated with them for a given country
    *
@@ -253,4 +289,23 @@ public function getListings(
     return static::getResource($response, "Listing");
   }
 
+  /**
+   * Find shops based on a shop name
+   *
+   * @param array $params
+   * @return Etsy\Collection[Etsy\Resources\Shop]
+   */
+  public function findShops(
+    array $params
+  ) {
+    if(!isset($params['shop_name'])) {
+      throw new ApiException("Etsy findShops operation expects a `shop_name` param.");
+    }
+    $response = static::$client->get(
+      "/application/shops",
+      $params
+    );
+    return static::getResource($response, "Shop");
+  }
+
 }
diff --git a/src/OAuth/Client.php b/src/OAuth/Client.php
index a6cd261..e213c6b 100644
--- a/src/OAuth/Client.php
+++ b/src/OAuth/Client.php
@@ -39,6 +39,11 @@ class Client {
    */
   protected $config = [];
 
+  /**
+   * @var array
+   */
+  public $headers = [];
+
   /**
    * Create a new instance of Client.
    *
@@ -79,11 +84,14 @@ public function setConfig($config) {
    * @param string $api_key
    * @return void
    */
-  public function setApiKey($api_key) {
-    $this->headers = [
-      'x-api-key' => $this->client_id,
-      'Authorization' => "Bearer {$api_key}"
+  public function setApiKey($api_key = null) {
+    $headers = [
+      'x-api-key' => $this->client_id
     ];
+    if ($api_key) {
+      $headers['Authorization'] = "Bearer {$api_key}";
+    }
+    $this->headers = $headers;
   }
 
   public function __call($method, $args) {
@@ -190,7 +198,8 @@ public function requestAccessToken(
       $response = json_decode($response->getBody(), false);
       return [
         'access_token' => $response->access_token,
-        'refresh_token' => $response->refresh_token
+        'refresh_token' => $response->refresh_token,
+        'expires_at' => (time() + $response->expires_in)
       ];
     }
     catch(\Exception $e) {
@@ -219,7 +228,8 @@ public function refreshAccessToken(
       $response = json_decode($response->getBody(), false);
       return [
         'access_token' => $response->access_token,
-        'refresh_token' => $response->refresh_token
+        'refresh_token' => $response->refresh_token,
+        'expires_at' => (time() + $response->expires_in)
       ];
     }
     catch(\Exception $e) {
@@ -248,7 +258,8 @@ public function exchangeLegacyToken(
       $response = json_decode($response->getBody(), false);
       return [
         'access_token' => $response->access_token,
-        'refresh_token' => $response->refresh_token
+        'refresh_token' => $response->refresh_token,
+        'expires_at' => (time() + $response->expires_in)
       ];
     }
     catch(\Exception $e) {
diff --git a/src/Resources/BuyerTaxonomy.php b/src/Resources/BuyerTaxonomy.php
new file mode 100644
index 0000000..8591aff
--- /dev/null
+++ b/src/Resources/BuyerTaxonomy.php
@@ -0,0 +1,28 @@
+<?php
+
+namespace Etsy\Resources;
+
+use Etsy\Resource;
+
+/**
+ * BuyerTaxonomy resource class. Represents a buyer taxonomy within Etsy. These are essentially categories used for listing.
+ *
+ * @link https://developers.etsy.com/documentation/reference/#tag/BuyerTaxonomy
+ * @author Andrew Christensen andrew@critical-code.com
+ */
+class BuyerTaxonomy extends Resource {
+
+  /**
+   * Get the properties for this Buyer Taxonomy node.
+   *
+   * @return \Etsy\Collection
+   */
+  public function getProperties() {
+    return $this->request(
+        'GET',
+        "/application/buyer-taxonomy/nodes/{$this->id}/properties",
+        "BuyerTaxonomyProperty"
+      );
+  }
+
+}
diff --git a/src/Resources/BuyerTaxonomyProperty.php b/src/Resources/BuyerTaxonomyProperty.php
new file mode 100644
index 0000000..1b82369
--- /dev/null
+++ b/src/Resources/BuyerTaxonomyProperty.php
@@ -0,0 +1,13 @@
+<?php
+
+namespace Etsy\Resources;
+
+use Etsy\Resource;
+
+/**
+ * BuyerTaxonomyProperty resource class. Represents an optional listing field for a specific buyer taxonomy.
+ *
+ * @link https://developers.etsy.com/documentation/reference/#operation/getPropertiesByBuyerTaxonomyId
+ * @author Andrew Christensen andrew@critical-code.com
+ */
+class BuyerTaxonomyProperty extends Resource {}
diff --git a/src/Resources/Listing.php b/src/Resources/Listing.php
index 6ee802f..59782cc 100644
--- a/src/Resources/Listing.php
+++ b/src/Resources/Listing.php
@@ -19,7 +19,11 @@ class Listing extends Resource {
   protected $_associations = [
     "Shop" => "Shop",
     "User" => "User",
-    "Images" => "Image"
+    "Images" => "Image",
+    "Translations" => "Translation",
+    "Inventory" => "Inventory",
+    "Videos" => "Video",
+    "Shipping" => "Shipping"
   ];
 
   /**
@@ -32,7 +36,8 @@ class Listing extends Resource {
   public function update(array $data) {
     return $this->updateRequest(
       "/application/shops/{$this->shop_id}/listings/{$this->listing_id}",
-      $data
+      $data,
+      'PATCH'
     );
   }
 
@@ -44,7 +49,7 @@ public function update(array $data) {
    */
   public function delete() {
     return $this->deleteRequest(
-      "/application/shops/{$this->shop_id}/listings/{$this->listing_id}"
+      "/application/listings/{$this->listing_id}"
     );
   }
 
@@ -153,7 +158,7 @@ public function uploadFile(array $data) {
   public function getImages() {
     return $this->request(
       "GET",
-      "/application/shops/{$this->shop_id}/listings/{$this->listing_id}/images",
+      "/application/listings/{$this->listing_id}/images",
       "ListingImage"
     )
       ->append(["shop_id" => $this->shop_id]);
@@ -169,7 +174,7 @@ public function getImages() {
   public function getImage($listing_image_id) {
     $listing_image = $this->request(
       "GET",
-      "/application/shops/{$this->shop_id}/listings/{$this->listing_id}/images/{$listing_image_id}",
+      "/application/listings/{$this->listing_id}/images/{$listing_image_id}",
       "ListingImage"
     );
     if($listing_image) {
@@ -177,7 +182,7 @@ public function getImage($listing_image_id) {
     }
     return $listing_image;
   }
-
+  
   /**
    * Upload a listing image.
    *
@@ -201,6 +206,63 @@ public function uploadImage(array $data) {
     return $listing_image;
   }
 
+  /**
+   * Get the Listing Videos for the listing.
+   *
+   * @link https://developers.etsy.com/documentation/reference#operation/getListingVideos
+   * @return Etsy\Collection[Etsy\Resources\ListingVideo]
+   */
+  public function getVideos() {
+    return $this->request(
+      "GET",
+      "/application/listings/{$this->listing_id}/videos",
+      "ListingVideo"
+    )
+      ->append(["shop_id" => $this->shop_id]);
+  }
+
+  /**
+   * Get a specific listing video.
+   *
+   * @link https://developers.etsy.com/documentation/reference#operation/getListingVideo
+   * @param integer|string $listing_video_id
+   * @return Etsy\Resources\ListingVideo
+   */
+  public function getVideo($listing_video_id) {
+    $listing_video = $this->request(
+      "GET",
+      "/application/listings/{$this->listing_id}/videos/{$listing_video_id}",
+      "ListingVideo"
+    );
+    if($listing_video) {
+      $listing_video->shop_id = $this->shop_id;
+    }
+    return $listing_video;
+  }
+  
+  /**
+   * Upload a listing video.
+   *
+   * @link https://developers.etsy.com/documentation/reference#operation/uploadListingVideo
+   * @param array $data
+   * @return Etsy\Resources\ListingVideo
+   */
+  public function uploadVideo(array $data) {
+    if(!isset($data['video']) && !isset($data['video_id'])) {
+      throw new ApiException("Request requires either 'video_id' or 'video' paramater.");
+    }
+    $listing_video = $this->request(
+      "POST",
+      "/application/shops/{$this->shop_id}/listings/{$this->listing_id}/videos",
+      "ListingVideo",
+      $data
+    );
+    if($listing_video) {
+      $listing_video->shop_id = $this->shop_id;
+    }
+    return $listing_video;
+  }
+
   /**
    * Get the inventory for the listing.
    *
@@ -247,6 +309,27 @@ public function updateInventory(array $data) {
     return $inventory;
   }
 
+  /**
+   * Get an offering for a listing. Use this method to bypass going through the ListingInventory resource.
+   *
+   * @link https://developers.etsy.com/documentation/reference#tag/ShopListing-Offering
+   * @param integer|string $product_id
+   * @param integer|string $product_offering_id
+   * @return Etsy\Resources\ListingOffering
+   */
+  public function getOffering($product_id, $product_offering_id) {
+    $offering = $this->request(
+      "GET",
+      "/application/listings/{$this->listing_id}/inventory/products/{$product_id}/offerings/{$product_offering_id}",
+      "ListingOffering"
+    );
+    if($offering) {
+      $offering->listing_id = $this->listing_id;
+      $offering->product_id = $product_id;
+    }
+    return $offering;
+  }
+
   /**
    * Get a specific product for a listing. Use this method to bypass going through the ListingInventory resource.
    *
@@ -341,4 +424,34 @@ public function updateVariationImages(array $data) {
     );
   }
 
+  /**
+   * Get all reviews for the listing.
+   *
+   * @param array $params
+   * @return Etsy\Collection[Etsy\Resources\Review]
+   */
+  public function getReviews(array $params = []) {
+    return $this->request(
+      "GET",
+      "/application/listings/{$this->listing_id}/reviews",
+      "Review",
+      $params
+    );
+  }
+
+  /**
+   * Get all transactions for the listing.
+   *
+   * @link https://developers.etsy.com/documentation/reference#operation/getShopReceiptTransactionsByListing
+   * @param array $params
+   * @return Etsy\Collection[Etsy\Resources\Transaction]
+   */
+  public function getTransactions(array $params = []) {
+    return $this->request(
+      "GET",
+      "/application/shops/{$this->shop_id}/listing/{$this->listing_id}/transactions",
+      "Transaction",
+      $params
+    );
+  }
 }
diff --git a/src/Resources/ListingVideo.php b/src/Resources/ListingVideo.php
new file mode 100644
index 0000000..423c98b
--- /dev/null
+++ b/src/Resources/ListingVideo.php
@@ -0,0 +1,25 @@
+<?php
+
+namespace Etsy\Resources;
+
+use Etsy\Resource;
+
+/**
+ * Listing Video class.
+ *
+ * @author Andrew Christensen andrew@critical-code.com
+ */
+class ListingVideo extends Resource {
+
+  /**
+   * Delete the listing video.
+   *
+   * @link https://developers.etsy.com/documentation/reference#operation/deleteListingVideo
+   * @return boolean
+   */
+  public function delete() {
+    return $this->deleteRequest(
+      "/application/shops/{$this->shop_id}/listings/{$this->listing_id}/videos/{$this->listing_video_id}"
+    );
+  }
+}
diff --git a/src/Resources/ProductionPartner.php b/src/Resources/ProductionPartner.php
new file mode 100644
index 0000000..77be23b
--- /dev/null
+++ b/src/Resources/ProductionPartner.php
@@ -0,0 +1,13 @@
+<?php
+
+namespace Etsy\Resources;
+
+use Etsy\Resource;
+
+/**
+ * ProductionPartner resource class. Represents a Etsy shop production partner.
+ *
+ * @link https://developers.etsy.com/documentation/reference/#tag/Shop-ProductionPartner
+ * @author Andrew Christensen andrew@critical-code.com
+ */
+class ProductionPartner extends Resource {}
diff --git a/src/Resources/ReturnPolicy.php b/src/Resources/ReturnPolicy.php
new file mode 100644
index 0000000..bb2b76f
--- /dev/null
+++ b/src/Resources/ReturnPolicy.php
@@ -0,0 +1,58 @@
+<?php
+
+namespace Etsy\Resources;
+
+use Etsy\Resource;
+
+/**
+ * ReturnPolicy resource class. Represents a Etsy shop return policy.
+ *
+ * @link https://developers.etsy.com/documentation/reference/#tag/Shop-Return-Policy
+ * @author Andrew Christensen andrew@critical-code.com
+ */
+class ReturnPolicy extends Resource {
+
+   /**
+   * Update the shop return policy.
+   *
+   * @link https://developers.etsy.com/documentation/reference#operation/updateShopReturnPolicy
+   * @param array $data
+   * @return Etsy\Resources\ReturnPolicy
+   */
+  public function update(array $data) {
+    return $this->updateRequest(
+      "/application/shops/{$this->shop_id}/policies/return/{$this->return_policy_id}",
+      $data,
+      'PUT'
+    );
+  }
+
+  /**
+   * Delete the return policy.
+   *
+   * @link https://developers.etsy.com/documentation/reference#operation/deleteShopReturnPolicy
+   * @return boolean
+   */
+  public function delete() {
+    return $this->deleteRequest(
+      "/application/shops/{$this->shop_id}/policies/return/{$this->return_policy_id}"
+    );
+  }
+
+
+   /**
+   * Get all listings associated with the shop return policy.
+   *
+   * @link https://developers.etsy.com/documentation/reference#operation/getListingsByShopReturnPolicy
+   * @param array $params
+   * @return Etsy\Collection[Etsy\Resources\Listing]
+   */
+  public function getListings() {
+    return $this->request(
+        "GET",
+        "/application/shops/{$this->shop_id}/policies/return/{$this->return_policy_id}/listings",
+        "Listing"
+      );
+  }
+
+}
diff --git a/src/Resources/Shop.php b/src/Resources/Shop.php
index 3428969..acc018e 100644
--- a/src/Resources/Shop.php
+++ b/src/Resources/Shop.php
@@ -78,6 +78,21 @@ public function createSection(string $title) {
     );
   }
 
+  /**
+   * Get all production partners for the shop.
+   *
+   * @param array $params
+   * @return \Etsy\Collection
+   */
+  public function getProductionPartners() {
+    return $this->request(
+      "GET",
+      "/application/shops/{$this->shop_id}/production-partners",
+      "ProductionPartner"
+    )
+      ->append(['shop_id' => $this->shop_id]);
+  }
+
   /**
    * Get all reviews for the shop.
    *
@@ -119,7 +134,7 @@ public function getShippingProfiles() {
    * Gets a single shipping profile for the shop.
    *
    * @param integer|string $shipping_profile_id
-   * @return Etsy\Resources\ShippingProfile
+   * @return Etsy\Collection[Etsy\Resources\ShippingProfile]
    */
   public function getShippingProfile($shipping_profile_id) {
     $profile = $this->request(
@@ -137,7 +152,7 @@ public function getShippingProfile($shipping_profile_id) {
    *
    * @link https://developers.etsy.com/documentation/reference/#operation/createShopShippingProfile
    * @param array $data
-   * @return Etsy\Resources\ShippingProfile
+   * @return Etsy\Collection[Etsy\Resources\ShippingProfile]
    */
   public function createShippingProfile(array $data) {
     $profile = $this->request(
@@ -151,6 +166,70 @@ public function createShippingProfile(array $data) {
     return $profile;
   }
 
+  /**
+   * Get all return policies for the shop.
+   *
+   * @return Etsy\Collection[Etsy\Resources\ReturnPolicy]
+   */
+  public function getReturnPolicies() {
+    $policies = $this->request(
+      "GET",
+      "/application/shops/{$this->shop_id}/policies/return",
+      "ReturnPolicy"
+    )->append(['shop_id' => $this->shop_id]);
+    return $policies;
+  }
+
+  /**
+   * Gets a single shipping profile for the shop.
+   *
+   * @param integer $policy_id
+   * @return Etsy\Resources\ReturnPolicy
+   */
+  public function getReturnPolicy($policy_id) {
+    $policy = $this->request(
+      "GET",
+      "/application/shops/{$this->shop_id}/shipping-profiles/{$policy_id}",
+      "ReturnPolicy"
+    );
+    return $policy;
+  }
+
+  /**
+   * Consolidate two shop return policies.
+   *
+   * @param integer $source_policy_id
+   * @param integer $destination_policy_id
+   * @return Etsy\Resources\ReturnPolicy
+   */
+  public function consolidateReturnPolicies(int $source_policy_id, int $destination_policy_id) {
+    $data = [
+      'source_policy_id' => $source_policy_id,
+      'destination_policy_id' => $destination_policy_id
+    ];
+    return $this->updateRequest(
+      "/application/shops/{$this->shop_id}/policies/return/consolidate",
+      $data,
+      'POST'
+    );
+  }
+  /**
+   * Creates a new return policy for the shop.
+   *
+   * @link https://developers.etsy.com/documentation/reference#operation/createShopReturnPolicy
+   * @param array $data
+   * @return Etsy\Resources\ReturnPolicy
+   */
+  public function createReturnPolicy(array $data) {
+    $policy = $this->request(
+      "POST",
+      "/application/shops/{$this->shop_id}/policies/return",
+      "ReturnPolicy",
+      $data
+    );
+    return $policy;
+  }
+
   /**
    * Assigns the shop ID to a shipping profile.
    *