diff --git a/.travis.yml b/.travis.yml
index 9b9f3b7..70c1660 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,8 +1,7 @@
 language: ruby
 rvm:
- - 2.0.0
- - 2.1.5
- - 2.2.1
- - 2.3.0
- - ruby-head
+ - 2.4
+ - 2.5
+ - 2.6
+ - 2.7
 script: bundle exec rake test
diff --git a/Gemfile b/Gemfile
index 9c451ee..7844371 100644
--- a/Gemfile
+++ b/Gemfile
@@ -6,5 +6,5 @@ gem "json"
 group :test do
   gem "rake"
   gem "minitest"
-  gem "fakeweb"
+  gem "webmock"
 end
diff --git a/Gemfile.lock b/Gemfile.lock
index b42e040..3bc12ac 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,23 +1,37 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    fakeweb (1.3.0)
-    httparty (0.14.0)
+    addressable (2.7.0)
+      public_suffix (>= 2.0.2, < 5.0)
+    crack (0.4.3)
+      safe_yaml (~> 1.0.0)
+    hashdiff (1.0.1)
+    httparty (0.18.1)
+      mime-types (~> 3.0)
       multi_xml (>= 0.5.2)
-    json (2.0.2)
-    minitest (5.10.1)
+    json (2.3.0)
+    mime-types (3.3.1)
+      mime-types-data (~> 3.2015)
+    mime-types-data (3.2020.0512)
+    minitest (5.14.1)
     multi_xml (0.6.0)
-    rake (12.0.0)
+    public_suffix (4.0.5)
+    rake (13.0.1)
+    safe_yaml (1.0.5)
+    webmock (3.8.3)
+      addressable (>= 2.3.6)
+      crack (>= 0.3.2)
+      hashdiff (>= 0.4.0, < 2.0.0)
 
 PLATFORMS
   ruby
 
 DEPENDENCIES
-  fakeweb
   httparty
   json
   minitest
   rake
+  webmock
 
 BUNDLED WITH
-   1.12.5
+   2.1.4
diff --git a/lib/woocommerce_api.rb b/lib/woocommerce_api.rb
index 4ef29b2..d363a31 100644
--- a/lib/woocommerce_api.rb
+++ b/lib/woocommerce_api.rb
@@ -97,7 +97,7 @@ def add_query_params endpoint, data
 
       endpoint += "?" unless endpoint.include? "?"
       endpoint += "&" unless endpoint.end_with? "?"
-      endpoint + URI.encode(flatten_hash(data).join("&"))
+      endpoint + URI.encode_www_form(flatten_hash(data))
     end
 
     # Internal: Get URL for requests
@@ -189,12 +189,12 @@ def flatten_hash hash
         case value
         when Hash
           value.map do |inner_key, inner_value|
-            "#{key}[#{inner_key}]=#{inner_value}"
+            ["#{key}[#{inner_key}]", "#{inner_value}"]
           end
         when Array
-          value.map { |inner_value| "#{key}[]=#{inner_value}" }
+          value.map { |inner_value| ["#{key}[]", "#{inner_value}"] }
         else
-          "#{key}=#{value}"
+          [["#{key}", "#{value}"]]
         end
       end
     end
diff --git a/lib/woocommerce_api/oauth.rb b/lib/woocommerce_api/oauth.rb
index c5bc44e..3df7c66 100644
--- a/lib/woocommerce_api/oauth.rb
+++ b/lib/woocommerce_api/oauth.rb
@@ -42,7 +42,7 @@ def get_oauth_url
       params["oauth_timestamp"] = Time.new.to_i
       params["oauth_signature"] = CGI::escape(generate_oauth_signature(params, url))
 
-      query_string = URI::encode(params.map{|key, value| "#{key}=#{value}"}.join("&"))
+      query_string = URI.encode_www_form(params)
 
       "#{url}?#{query_string}"
     end
diff --git a/test/test.rb b/test/test.rb
index 58f25f8..d273805 100644
--- a/test/test.rb
+++ b/test/test.rb
@@ -1,5 +1,5 @@
 require "minitest/autorun"
-require "fakeweb"
+require 'webmock/minitest'
 require "json"
 require "woocommerce_api"
 
@@ -19,9 +19,11 @@ def setup
   end
 
   def test_basic_auth_get
-    FakeWeb.register_uri(:get, "https://user:pass@dev.test/wc-api/v3/customers",
-      body: '{"customers":[]}',
-      content_type: "application/json"
+    stub_request(:get, "https://dev.test/wc-api/v3/customers")
+      .with(headers: { 'Authorization'=>'Basic dXNlcjpwYXNz' })
+      .to_return(
+        body: '{"customers":[]}',
+        headers: { content_type: "application/json" },
     )
     response = @basic_auth.get "customers"
 
@@ -29,9 +31,9 @@ def test_basic_auth_get
   end
 
   def test_oauth_get
-    FakeWeb.register_uri(:get, /http:\/\/dev\.test\/wc-api\/v3\/customers\?oauth_consumer_key=user&oauth_nonce=(.*)&(.*)oauth_signature_method=HMAC-SHA256&oauth_timestamp=(.*)/,
+    stub_request(:get, /http:\/\/dev\.test\/wc-api\/v3\/customers\?oauth_consumer_key=user&oauth_nonce=(.*)&(.*)oauth_signature_method=HMAC-SHA256&oauth_timestamp=(.*)/).and_return(
       body: '{"customers":[]}',
-      content_type: "application/json"
+      headers: { content_type: "application/json" },
     )
     response = @oauth.get "customers"
 
@@ -39,9 +41,9 @@ def test_oauth_get
   end
 
   def test_oauth_get_puts_data_in_alpha_order
-    FakeWeb.register_uri(:get, /http:\/\/dev\.test\/wc-api\/v3\/customers\?abc=123&oauth_consumer_key=user&oauth_d=456&oauth_nonce=(.*)&(.*)oauth_signature_method=HMAC-SHA256&oauth_timestamp=(.*)&xyz=789/,
+    stub_request(:get, /http:\/\/dev\.test\/wc-api\/v3\/customers\?abc=123&oauth_consumer_key=user&oauth_d=456&oauth_nonce=(.*)&(.*)oauth_signature_method=HMAC-SHA256&oauth_timestamp=(.*)&xyz=789/).and_return(
       body: '{"customers":[]}',
-      content_type: "application/json"
+      headers: { content_type: "application/json" },
     )
     response = @oauth.get "customers", abc: '123', oauth_d: '456', xyz: '789'
 
@@ -49,10 +51,12 @@ def test_oauth_get_puts_data_in_alpha_order
   end
 
   def test_basic_auth_post
-    FakeWeb.register_uri(:post, "https://user:pass@dev.test/wc-api/v3/products",
-      body: '{"products":[]}',
-      content_type: "application/json",
-      status: ["201", "Created"]
+    stub_request(:post, "https://dev.test/wc-api/v3/products")
+      .with(headers: { 'Authorization'=>'Basic dXNlcjpwYXNz' })
+      .to_return(
+        body: '{"products":[]}',
+        headers: { content_type: "application/json" },
+        status: 201
     )
 
     data = {
@@ -66,10 +70,10 @@ def test_basic_auth_post
   end
 
   def test_oauth_post
-    FakeWeb.register_uri(:post, /http:\/\/dev\.test\/wc-api\/v3\/products\?oauth_consumer_key=user&oauth_nonce=(.*)&(.*)oauth_signature_method=HMAC-SHA256&oauth_timestamp=(.*)/,
+    stub_request(:post, /http:\/\/dev\.test\/wc-api\/v3\/products\?oauth_consumer_key=user&oauth_nonce=(.*)&(.*)oauth_signature_method=HMAC-SHA256&oauth_timestamp=(.*)/).and_return(
       body: '{"products":[]}',
-      content_type: "application/json",
-      status: ["201", "Created"]
+      headers: { content_type: "application/json" },
+      status: 201
     )
 
     data = {
@@ -83,10 +87,16 @@ def test_oauth_post
   end
 
   def test_basic_auth_put
-    FakeWeb.register_uri(:put, "https://user:pass@dev.test/wc-api/v3/products/1234",
-      body: '{"customers":[]}',
-      content_type: "application/json"
-    )
+    stub_request(:put, "https://dev.test/wc-api/v3/products/1234").
+      with(
+        body: "{\"product\":{\"title\":\"Updating product title\"}}",
+        headers: {
+          'Authorization'=>'Basic dXNlcjpwYXNz',
+        }).
+        to_return(
+          body: '{"customers":[]}',
+          headers: { content_type: "application/json" }
+        )
 
     data = {
       product: {
@@ -99,9 +109,9 @@ def test_basic_auth_put
   end
 
   def test_oauth_put
-    FakeWeb.register_uri(:put, /http:\/\/dev\.test\/wc-api\/v3\/products\?oauth_consumer_key=user&oauth_nonce=(.*)&(.*)oauth_signature_method=HMAC-SHA256&oauth_timestamp=(.*)/,
+    stub_request(:put, /http:\/\/dev\.test\/wc-api\/v3\/products\?oauth_consumer_key=user&oauth_nonce=(.*)&(.*)oauth_signature_method=HMAC-SHA256&oauth_timestamp=(.*)/).and_return(
       body: '{"products":[]}',
-      content_type: "application/json"
+      headers: { content_type: "application/json" },
     )
 
     data = {
@@ -115,47 +125,57 @@ def test_oauth_put
   end
 
   def test_basic_auth_delete
-    FakeWeb.register_uri(:delete, "https://user:pass@dev.test/wc-api/v3/products/1234?force=true",
-      body: '{"message":"Permanently deleted product"}',
-      content_type: "application/json",
-      status: ["202", "Accepted"]
-    )
+    stub_request(:delete, "https://dev.test/wc-api/v3/products/1234?force=true").
+      with(
+        headers: {
+          'Authorization'=>'Basic dXNlcjpwYXNz',
+        }).
+        to_return(
+          body: '{"message":"Permanently deleted product"}',
+          headers: { content_type: "application/json" },
+          status: 202,
+        )
 
     response = @basic_auth.delete "products/1234?force=true"
 
     assert_equal 202, response.code
-    assert_equal '{"message":"Permanently deleted product"}', response.to_json
+    assert_equal '{"message":"Permanently deleted product"}', response.body
   end
 
   def test_basic_auth_delete_params
-    FakeWeb.register_uri(:delete, "https://user:pass@dev.test/wc-api/v3/products/1234?force=true",
-      body: '{"message":"Permanently deleted product"}',
-      content_type: "application/json",
-      status: ["202", "Accepted"]
-    )
+    stub_request(:delete, "https://dev.test/wc-api/v3/products/1234?force=true").
+      with(
+        headers: {
+          'Authorization'=>'Basic dXNlcjpwYXNz',
+        }).
+        to_return(
+          body: '{"message":"Permanently deleted product"}',
+          headers: { content_type: "application/json" },
+          status: 202,
+        )
 
     response = @basic_auth.delete "products/1234", force: true
 
     assert_equal 202, response.code
-    assert_equal '{"message":"Permanently deleted product"}', response.to_json
+    assert_equal '{"message":"Permanently deleted product"}', response.body
   end
 
-  def test_oauth_put
-    FakeWeb.register_uri(:delete, /http:\/\/dev\.test\/wc-api\/v3\/products\/1234\?force=true&oauth_consumer_key=user&oauth_nonce=(.*)&(.*)oauth_signature_method=HMAC-SHA256&oauth_timestamp=(.*)/,
+  def test_oauth_delete
+    stub_request(:delete, /http:\/\/dev\.test\/wc-api\/v3\/products\/1234\?force=true&oauth_consumer_key=user&oauth_nonce=(.*)&(.*)oauth_signature_method=HMAC-SHA256&oauth_timestamp=(.*)/).and_return(
       body: '{"message":"Permanently deleted product"}',
-      content_type: "application/json",
-      status: ["202", "Accepted"]
+      headers: { content_type: "application/json" },
+      status: 202
     )
 
     response = @oauth.delete "products/1234?force=true"
 
     assert_equal 202, response.code
-    assert_equal '{"message":"Permanently deleted product"}', response.to_json
+    assert_equal '{"message":"Permanently deleted product"}', response.body
   end
 
   def test_adding_query_params
     url = @oauth.send(:add_query_params, 'foo.com', filter: { sku: '123' }, order: 'created_at')
-    assert_equal url, URI.encode('foo.com?filter[sku]=123&order=created_at')
+    assert_equal url, 'foo.com?filter%5Bsku%5D=123&order=created_at'
   end
 
   def test_invalid_signature_method