diff --git a/CHANGES.md b/CHANGES.md
index a4c08999..1d708345 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,4 +1,4 @@
-## [4.2.0](https://github.com/Nexmo/ruby-nexmo/tree/v4.2.0)
+# 4.2.0
 
 * Added get_sms_pricing method
 
@@ -10,7 +10,7 @@
 
 * Added more clearly named methods for Verify API
 
-## [4.1.0](https://github.com/Nexmo/ruby-nexmo/tree/v4.1.0)
+# 4.1.0
 
 * Added topup method
 
@@ -18,7 +18,7 @@
 
 * Added api_host option
 
-## [4.0.0](https://github.com/Nexmo/ruby-nexmo/tree/v4.0.0)
+# 4.0.0
 
 * Removed exception behaviour from #send_message
 
@@ -44,13 +44,13 @@
 
 * Changed license from LGPL-3.0 to MIT
 
-## [3.1.0](https://github.com/Nexmo/ruby-nexmo/tree/v3.1.0)
+# 3.1.0
 
 * Renamed #number_search method to #get_available_numbers
 
 * Added #control_verification_request method
 
-## [3.0.0](https://github.com/Nexmo/ruby-nexmo/tree/v3.0.0)
+# 3.0.0
 
 * Removed :http accessor
 
@@ -64,7 +64,7 @@
 
 * Added license info
 
-## [2.0.0](https://github.com/Nexmo/ruby-nexmo/tree/v2.0.0)
+# 2.0.0
 
 * Dropped support for Ruby 1.8.7
 
@@ -88,7 +88,7 @@
 
 * Added Voice API methods
 
-## [1.3.0](https://github.com/Nexmo/ruby-nexmo/tree/v1.3.0)
+# 1.3.0
 
 * Added Nexmo::Client#buy_number method
 
@@ -98,19 +98,19 @@
 
 * Added :host option for specifying a different hostname to connect to
 
-## [1.2.0](https://github.com/Nexmo/ruby-nexmo/tree/v1.2.0)
+# 1.2.0
 
 * Added initializer block functionality for tweaking response behaviour
 
 * Deprecated the :json option (use an initializer block instead)
 
-## [1.1.0](https://github.com/Nexmo/ruby-nexmo/tree/v1.1.0)
+# 1.1.0
 
 * Added default lookup of NEXMO_API_KEY and NEXMO_API_SECRET environment variables
 
 * Added preliminary/experimental support for [Nexmo OAuth](https://labs.nexmo.com/#oauth) (beta)
 
-## [1.0.0](https://github.com/Nexmo/ruby-nexmo/tree/v1.0.0)
+# 1.0.0
 
 * Ruby 1.8.7 compatibility
 
@@ -118,7 +118,7 @@
 
 * Added Nexmo::Client#send_message! method
 
-## [0.5.0](https://github.com/Nexmo/ruby-nexmo/tree/v0.5.0)
+# 0.5.0
 
 * Added Nexmo::Client#search_messages method
 
@@ -126,7 +126,7 @@
 
 * Added :json option for specifying an alternate JSON implementation
 
-## [0.4.0](https://github.com/Nexmo/ruby-nexmo/tree/v0.4.0)
+# 0.4.0
 
 * Added Nexmo::Client#get_balance method
 
@@ -142,30 +142,30 @@
 
 * Added Nexmo::Client#get_message_rejections method
 
-## [0.3.1](https://github.com/Nexmo/ruby-nexmo/tree/v0.3.1)
+# 0.3.1
 
 * Fixed content type checking (thanks @dbrock)
 
-## [0.3.0](https://github.com/Nexmo/ruby-nexmo/tree/v0.3.0)
+# 0.3.0
 
 * Fixed Nexmo::Client#send_message for unexpected HTTP responses
 
-## [0.2.2](https://github.com/Nexmo/ruby-nexmo/tree/v0.2.2)
+# 0.2.2
 
 * Added Nexmo status code to error messages
 
-## [0.2.1](https://github.com/Nexmo/ruby-nexmo/tree/v0.2.1)
+# 0.2.1
 
 * No significant changes
 
-## [0.2.0](https://github.com/Nexmo/ruby-nexmo/tree/v0.2.0)
+# 0.2.0
 
 * Added Nexmo::Client#headers method
 
-## [0.1.1](https://github.com/Nexmo/ruby-nexmo/tree/v0.1.1)
+# 0.1.1
 
 * Ruby 1.8.7 compatibility
 
-## [0.1.0](https://github.com/Nexmo/ruby-nexmo/tree/v0.1.0)
+# 0.1.0
 
 * First version!
diff --git a/README.md b/README.md
index dc81f21f..559b7558 100644
--- a/README.md
+++ b/README.md
@@ -8,7 +8,10 @@ need a Nexmo account. Sign up [for free at nexmo.com][signup].
 
 * [Installation](#installation)
 * [Usage](#usage)
-* [Examples](#examples)
+* [SMS API](#sms-api)
+* [Voice API](#voice-api)
+* [Verify API](#verify-api)
+* [Application API](#application-api)
 * [Coverage](#api-coverage)
 * [License](#license)
 
@@ -28,33 +31,36 @@ Alternatively you can clone the repository:
 Usage
 -----
 
-Specify your credentials using the `NEXMO_API_KEY` and `NEXMO_API_SECRET`
-environment variables; require the nexmo library; and construct a client object.
-For example:
+Begin by requiring the nexmo library:
 
 ```ruby
 require 'nexmo'
-
-client = Nexmo::Client.new
 ```
 
-Alternatively you can specify your credentials directly using the `key`
-and `secret` options:
+Then construct a client object with your key and secret:
 
 ```ruby
-require 'nexmo'
-
 client = Nexmo::Client.new(key: 'YOUR-API-KEY', secret: 'YOUR-API-SECRET')
 ```
 
+For production you can specify the `NEXMO_API_KEY` and `NEXMO_API_SECRET`
+environment variables instead of specifying the key and secret explicitly.
+
+For newer endpoints that support JWT authentication such as the Voice API,
+you can also specify the `application_id` and `private_key` arguments:
+
+```ruby
+client = Nexmo::Client.new(application_id: application_id, private_key: private_key)
+```
 
-Examples
---------
+In order to check signatures for incoming webhook requests, you'll also need
+to specify the `signature_secret` argument (or the `NEXMO_SIGNATURE_SECRET`
+environment variable).
 
-### Sending a message
 
-To use [Nexmo's SMS API][doc_sms] to send an SMS message, call the Nexmo::Client#send_message
-method with a hash containing the API parameters. For example:
+## SMS API
+
+### Send a text message
 
 ```ruby
 response = client.send_message(from: 'Ruby', to: 'YOUR NUMBER', text: 'Hello world')
@@ -66,72 +72,109 @@ else
 end
 ```
 
-Specify `type: 'unicode'` if sending unicode characters. For example:
+Docs: [https://docs.nexmo.com/messaging/sms-api/api-reference#request](https://docs.nexmo.com/messaging/sms-api/api-reference#request?utm_source=DEV_REL&utm_medium=github&utm_campaign=ruby-client-library)
+
+
+## Voice API
+
+### Make a call
 
 ```ruby
-response = client.send_message(from: 'Ruby', to: 'YOUR NUMBER', text: "Unicode \u2713", type: 'unicode')
+response = client.create_call({
+  to: [{type: 'phone', number: '14843331234'}],
+  from: {type: 'phone', number: '14843335555'},
+  answer_url: ['https://example.com/answer']
+})
 ```
 
-Specify phone numbers in international format, prefixed with country code.
+Docs: [https://docs.nexmo.com/voice/voice-api/api-reference#call_create](https://docs.nexmo.com/voice/voice-api/api-reference#call_create?utm_source=DEV_REL&utm_medium=github&utm_campaign=ruby-client-library)
 
-Check `response['messages'][0]['status']` to see if the message was sent
-successfully or if there was an error with the request.
+### Retrieve a list of calls
 
-Country specific restrictions may apply. For example, US messages must
-originate from either a pre-approved long number or short code.
+```ruby
+response = client.get_calls
+```
 
-### Fetching a message
+Docs: [https://docs.nexmo.com/voice/voice-api/api-reference#call_retrieve](https://docs.nexmo.com/voice/voice-api/api-reference#call_retrieve?utm_source=DEV_REL&utm_medium=github&utm_campaign=ruby-client-library)
 
-You can retrieve a message log from the API using the ID of the message:
+### Retrieve a single call
 
 ```ruby
-message = client.get_message('02000000DA7C52E7')
+response = client.get_call(uuid)
+```
+
+Docs: [https://docs.nexmo.com/voice/voice-api/api-reference#call_retrieve_single](https://docs.nexmo.com/voice/voice-api/api-reference#call_retrieve_single?utm_source=DEV_REL&utm_medium=github&utm_campaign=ruby-client-library)
+
+### Update a call
 
-puts "The body of the message was: #{message['body']}"
+```ruby
+response = client.update_call(uuid, action: 'hangup')
 ```
 
-### Starting a verification
+Docs: [https://docs.nexmo.com/voice/voice-api/api-reference#call_modify_single](https://docs.nexmo.com/voice/voice-api/api-reference#call_modify_single?utm_source=DEV_REL&utm_medium=github&utm_campaign=ruby-client-library)
+
+### Stream audio to a call
+
+```ruby
+stream_url = 'https://nexmo-community.github.io/ncco-examples/assets/voice_api_audio_streaming.mp3'
+
+response = client.send_audio(uuid, stream_url: stream_url)
+```
 
-Nexmo's [Verify API][doc_verify] makes it easy to prove that a user has provided their
-own phone number during signup, or implement second factor authentication during signin.
+Docs: [https://docs.nexmo.com/voice/voice-api/api-reference#stream_put](https://docs.nexmo.com/voice/voice-api/api-reference#stream_put?utm_source=DEV_REL&utm_medium=github&utm_campaign=ruby-client-library)
 
-You can start the verification process by calling the start_verification method:
+### Stop streaming audio to a call
 
 ```ruby
-response = client.start_verification(number: '441632960960', brand: 'MyApp')
+response = client.stop_audio(uuid)
+```
 
-if response['status'] == '0'
-  puts "Started verification request_id=#{response['request_id']}"
-else
-  puts "Error: #{response['error_text']}"
-end
+Docs: [https://docs.nexmo.com/voice/voice-api/api-reference#stream_delete](https://docs.nexmo.com/voice/voice-api/api-reference#stream_delete?utm_source=DEV_REL&utm_medium=github&utm_campaign=ruby-client-library)
+
+### Send a synthesized speech message to a call
+
+```ruby
+response = client.send_speech(uuid, text: 'Hello')
 ```
 
-The response contains a verification request id which you will need to
-store temporarily (in the session, database, url etc).
+Docs: [https://docs.nexmo.com/voice/voice-api/api-reference#talk_put](https://docs.nexmo.com/voice/voice-api/api-reference#talk_put?utm_source=DEV_REL&utm_medium=github&utm_campaign=ruby-client-library)
+
+### Stop sending a synthesized speech message to a call
+
+```ruby
+response = client.stop_speech(uuid)
+```
 
-### Controlling a verification
+Docs: [https://docs.nexmo.com/voice/voice-api/api-reference#talk_delete](https://docs.nexmo.com/voice/voice-api/api-reference#talk_delete?utm_source=DEV_REL&utm_medium=github&utm_campaign=ruby-client-library)
 
-Call the cancel_verification method with the verification request id
-to cancel an in-progress verification:
+### Send DTMF tones to a call
 
 ```ruby
-client.cancel_verification('00e6c3377e5348cdaf567e1417c707a5')
+response = client.send_dtmf(uuid, digits: '1234')
 ```
 
-Call the trigger_next_verification_event method with the verification
-request id to trigger the next attempt to send the confirmation code:
+Docs: [https://docs.nexmo.com/voice/voice-api/api-reference#dtmf_put](https://docs.nexmo.com/voice/voice-api/api-reference#dtmf_put?utm_source=DEV_REL&utm_medium=github&utm_campaign=ruby-client-library)
+
+
+## Verify API
+
+### Start a verification
 
 ```ruby
-client.trigger_next_verification_event('00e6c3377e5348cdaf567e1417c707a5')
+response = client.start_verification(number: '441632960960', brand: 'MyApp')
+
+if response['status'] == '0'
+  puts "Started verification request_id=#{response['request_id']}"
+else
+  puts "Error: #{response['error_text']}"
+end
 ```
 
-The verification request id comes from the call to the start_verification method.
+Docs: [https://docs.nexmo.com/verify/api-reference/api-reference#vrequest](https://docs.nexmo.com/verify/api-reference/api-reference#vrequest?utm_source=DEV_REL&utm_medium=github&utm_campaign=ruby-client-library)
 
-### Checking a verification
+The response contains a verification request id which you will need to store temporarily.
 
-Call the check_verification method with the verification request id and the
-PIN code to complete the verification process:
+### Check a verification
 
 ```ruby
 response = client.check_verification('00e6c3377e5348cdaf567e1417c707a5', code: '1234')
@@ -143,9 +186,88 @@ else
 end
 ```
 
+Docs: [https://docs.nexmo.com/verify/api-reference/api-reference#check](https://docs.nexmo.com/verify/api-reference/api-reference#check?utm_source=DEV_REL&utm_medium=github&utm_campaign=ruby-client-library)
+
 The verification request id comes from the call to the start_verification method.
+
 The PIN code is entered into your application by the user.
 
+### Cancel a verification
+
+```ruby
+client.cancel_verification('00e6c3377e5348cdaf567e1417c707a5')
+```
+
+Docs: [https://docs.nexmo.com/verify/api-reference/api-reference#control](https://docs.nexmo.com/verify/api-reference/api-reference#control?utm_source=DEV_REL&utm_medium=github&utm_campaign=ruby-client-library)
+
+### Trigger next verification step
+
+```ruby
+client.trigger_next_verification_event('00e6c3377e5348cdaf567e1417c707a5')
+```
+
+Docs: [https://docs.nexmo.com/verify/api-reference/api-reference#control](https://docs.nexmo.com/verify/api-reference/api-reference#control?utm_source=DEV_REL&utm_medium=github&utm_campaign=ruby-client-library?utm_source=DEV_REL&utm_medium=github&utm_campaign=ruby-client-library)
+
+
+## Application API
+
+### Create an application
+
+```ruby
+response = client.create_application(name: 'Example App', type: 'voice', answer_url: answer_url)
+```
+
+Docs: [https://docs.nexmo.com/tools/application-api/api-reference#create](https://docs.nexmo.com/tools/application-api/api-reference#create?utm_source=DEV_REL&utm_medium=github&utm_campaign=ruby-client-library)
+
+### Retrieve a list of applications
+
+```ruby
+response = client.get_applications
+```
+
+Docs: [https://docs.nexmo.com/tools/application-api/api-reference#list](https://docs.nexmo.com/tools/application-api/api-reference#list?utm_source=DEV_REL&utm_medium=github&utm_campaign=ruby-client-library)
+
+### Retrieve a single application
+
+```ruby
+response = client.get_application(uuid)
+```
+
+Docs: [https://docs.nexmo.com/tools/application-api/api-reference#retrieve](https://docs.nexmo.com/tools/application-api/api-reference#retrieve?utm_source=DEV_REL&utm_medium=github&utm_campaign=ruby-client-library)
+
+### Update an application
+
+```ruby
+response = client.update_application(uuid, answer_method: 'POST')
+```
+
+Docs: [https://docs.nexmo.com/tools/application-api/api-reference#update](https://docs.nexmo.com/tools/application-api/api-reference#update?utm_source=DEV_REL&utm_medium=github&utm_campaign=ruby-client-library)
+
+### Delete an application
+
+```ruby
+response = client.delete_application(uuid)
+```
+
+Docs: [https://docs.nexmo.com/tools/application-api/api-reference#delete](https://docs.nexmo.com/tools/application-api/api-reference#delete?utm_source=DEV_REL&utm_medium=github&utm_campaign=ruby-client-library)
+
+
+## Validate webhook signatures
+
+```ruby
+client = Nexmo::Client.new(signature_secret: 'secret')
+
+if client.check_signature(request.params):
+  # valid signature
+else:
+  # invalid signature
+```
+
+Docs: [https://docs.nexmo.com/messaging/signing-messages](https://docs.nexmo.com/messaging/signing-messages?utm_source=DEV_REL&utm_medium=github&utm_campaign=ruby-client-library)
+
+Note: you'll need to contact support@nexmo.com to enable message signing on
+your account before you can validate webhook signatures.
+
 
 API Coverage
 ------------
@@ -196,6 +318,4 @@ License
 This library is released under the [MIT License][license]
 
 [signup]: https://dashboard.nexmo.com/sign-up?utm_source=DEV_REL&utm_medium=github&utm_campaign=ruby-client-library
-[doc_sms]: https://docs.nexmo.com/messaging/sms-api?utm_source=DEV_REL&utm_medium=github&utm_campaign=ruby-client-library
-[doc_verify]: https://docs.nexmo.com/verify/api-reference?utm_source=DEV_REL&utm_medium=github&utm_campaign=ruby-client-library
 [license]: LICENSE.txt
diff --git a/lib/nexmo.rb b/lib/nexmo.rb
index b4e914f1..e4545c2d 100644
--- a/lib/nexmo.rb
+++ b/lib/nexmo.rb
@@ -1,17 +1,15 @@
 require 'nexmo/version'
+require 'nexmo/params'
+require 'nexmo/jwt'
+require 'nexmo/signature'
+require 'nexmo/errors/error'
+require 'nexmo/errors/client_error'
+require 'nexmo/errors/server_error'
+require 'nexmo/errors/authentication_error'
 require 'net/http'
 require 'json'
-require 'cgi'
 
 module Nexmo
-  class Error < StandardError; end
-
-  class ClientError < Error; end
-
-  class ServerError < Error; end
-
-  class AuthenticationError < ClientError; end
-
   class Client
     attr_accessor :key, :secret
 
@@ -20,6 +18,12 @@ def initialize(options = {})
 
       @secret = options.fetch(:secret) { ENV.fetch('NEXMO_API_SECRET') }
 
+      @signature_secret = options.fetch(:signature_secret) { ENV['NEXMO_SIGNATURE_SECRET'] }
+
+      @application_id = options[:application_id]
+
+      @private_key = options[:private_key]
+
       @host = options.fetch(:host) { 'rest.nexmo.com' }
 
       @api_host = options.fetch(:api_host) { 'api.nexmo.com' }
@@ -134,14 +138,20 @@ def sns_subscribe(recipient, params)
     end
 
     def initiate_call(params)
+      Kernel.warn "#{self.class}##{__method__} is deprecated (use the Voice API instead)."
+
       post(@host, '/call/json', params)
     end
 
     def initiate_tts_call(params)
+      Kernel.warn "#{self.class}##{__method__} is deprecated (use the Voice API instead)."
+
       post(@api_host, '/tts/json', params)
     end
 
     def initiate_tts_prompt_call(params)
+      Kernel.warn "#{self.class}##{__method__} is deprecated (use the Voice API instead)."
+
       post(@api_host, '/tts-prompt/json', params)
     end
 
@@ -201,16 +211,75 @@ def request_number_insight(params)
       post(@host, '/ni/json', params)
     end
 
+    def get_applications(params = {})
+      get(@api_host, '/v1/applications', params)
+    end
+
+    def get_application(id)
+      get(@api_host, "/v1/applications/#{id}")
+    end
+
+    def create_application(params)
+      post(@api_host, '/v1/applications', params)
+    end
+
+    def update_application(id, params)
+      put(@api_host, "/v1/applications/#{id}", params)
+    end
+
+    def delete_application(id)
+      delete(@api_host, "/v1/applications/#{id}")
+    end
+
+    def create_call(params)
+      api_request(Net::HTTP::Post, '/v1/calls', params)
+    end
+
+    def get_calls(params = nil)
+      api_request(Net::HTTP::Get, '/v1/calls', params)
+    end
+
+    def get_call(uuid)
+      api_request(Net::HTTP::Get, "/v1/calls/#{uuid}")
+    end
+
+    def update_call(uuid, params)
+      api_request(Net::HTTP::Put, "/v1/calls/#{uuid}", params)
+    end
+
+    def send_audio(uuid, params)
+      api_request(Net::HTTP::Put, "/v1/calls/#{uuid}/stream", params)
+    end
+
+    def stop_audio(uuid)
+      api_request(Net::HTTP::Delete, "/v1/calls/#{uuid}/stream")
+    end
+
+    def send_speech(uuid, params)
+      api_request(Net::HTTP::Put, "/v1/calls/#{uuid}/talk", params)
+    end
+
+    def stop_speech(uuid)
+      api_request(Net::HTTP::Delete, "/v1/calls/#{uuid}/talk")
+    end
+
+    def send_dtmf(uuid, params)
+      api_request(Net::HTTP::Put, "/v1/calls/#{uuid}/dtmf", params)
+    end
+
+    def check_signature(params)
+      Signature.check(params, @signature_secret)
+    end
+
     private
 
     def get(host, request_uri, params = {})
       uri = URI('https://' + host + request_uri)
-      uri.query = query_string(params.merge(api_key: @key, api_secret: @secret))
+      uri.query = Params.encode(params.merge(api_key: @key, api_secret: @secret))
 
       message = Net::HTTP::Get.new(uri.request_uri)
-      message['User-Agent'] = @user_agent
 
-      parse(request(uri, message), host)
+      request(uri, message)
     end
 
     def post(host, request_uri, params)
@@ -218,19 +287,60 @@ def post(host, request_uri, params)
 
       message = Net::HTTP::Post.new(uri.request_uri)
       message.form_data = params.merge(api_key: @key, api_secret: @secret)
-      message['User-Agent'] = @user_agent
 
-      parse(request(uri, message), host)
+      request(uri, message)
+    end
+
+    def put(host, request_uri, params)
+      uri = URI('https://' + host + request_uri)
+
+      message = Net::HTTP::Put.new(uri.request_uri)
+      message.form_data = params.merge(api_key: @key, api_secret: @secret)
+
+      request(uri, message)
+    end
+
+    def delete(host, request_uri)
+      uri = URI('https://' + host + request_uri)
+      uri.query = Params.encode({api_key: @key, api_secret: @secret})
+
+      message = Net::HTTP::Delete.new(uri.request_uri)
+
+      request(uri, message)
+    end
+
+    def api_request(message_class, path, params = nil)
+      uri = URI('https://' + @api_host + path)
+
+      unless message_class::REQUEST_HAS_BODY || params.nil? || params.empty?
+        uri.query = Params.encode(params)
+      end
+
+      message = message_class.new(uri.request_uri)
+
+      if message_class::REQUEST_HAS_BODY
+        message['Content-Type'] = 'application/json'
+        message.body = JSON.generate(params)
+      end
+
+      auth_payload = {application_id: @application_id}
+
+      message['Authorization'] = JWT.auth_header(auth_payload, @private_key)
+
+      request(uri, message)
     end
 
     def request(uri, message)
       http = Net::HTTP.new(uri.host, Net::HTTP.https_default_port)
       http.use_ssl = true
-      http.request(message)
-    end
 
-    def parse(http_response, host)
+      message['User-Agent'] = @user_agent
+
+      http_response = http.request(message)
+
       case http_response
+      when Net::HTTPNoContent
+        :no_content
       when Net::HTTPSuccess
         if http_response['Content-Type'].split(';').first == 'application/json'
           JSON.parse(http_response.body)
@@ -238,22 +348,14 @@ def parse(http_response, host)
           http_response.body
         end
       when Net::HTTPUnauthorized
-        raise AuthenticationError, "#{http_response.code} response from #{host}"
+        raise AuthenticationError, "#{http_response.code} response from #{uri.host}"
       when Net::HTTPClientError
-        raise ClientError, "#{http_response.code} response from #{host}"
+        raise ClientError, "#{http_response.code} response from #{uri.host}"
       when Net::HTTPServerError
-        raise ServerError, "#{http_response.code} response from #{host}"
+        raise ServerError, "#{http_response.code} response from #{uri.host}"
       else
-        raise Error, "#{http_response.code} response from #{host}"
+        raise Error, "#{http_response.code} response from #{uri.host}"
       end
     end
-
-    def query_string(params)
-      params.flat_map { |k, vs| Array(vs).map { |v| "#{escape(k)}=#{escape(v)}" } }.join('&')
-    end
-
-    def escape(component)
-      CGI.escape(component.to_s)
-    end
   end
 end
diff --git a/lib/nexmo/errors/authentication_error.rb b/lib/nexmo/errors/authentication_error.rb
new file mode 100644
index 00000000..433a7d24
--- /dev/null
+++ b/lib/nexmo/errors/authentication_error.rb
@@ -0,0 +1,4 @@
+module Nexmo
+  class AuthenticationError < ClientError
+  end
+end
diff --git a/lib/nexmo/errors/client_error.rb b/lib/nexmo/errors/client_error.rb
new file mode 100644
index 00000000..c7092858
--- /dev/null
+++ b/lib/nexmo/errors/client_error.rb
@@ -0,0 +1,4 @@
+module Nexmo
+  class ClientError < Error
+  end
+end
diff --git a/lib/nexmo/errors/error.rb b/lib/nexmo/errors/error.rb
new file mode 100644
index 00000000..64972800
--- /dev/null
+++ b/lib/nexmo/errors/error.rb
@@ -0,0 +1,4 @@
+module Nexmo
+  class Error < StandardError
+  end
+end
diff --git a/lib/nexmo/errors/server_error.rb b/lib/nexmo/errors/server_error.rb
new file mode 100644
index 00000000..929f93f7
--- /dev/null
+++ b/lib/nexmo/errors/server_error.rb
@@ -0,0 +1,4 @@
+module Nexmo
+  class ServerError < Error
+  end
+end
diff --git a/lib/nexmo/jwt.rb b/lib/nexmo/jwt.rb
new file mode 100644
index 00000000..37c3085c
--- /dev/null
+++ b/lib/nexmo/jwt.rb
@@ -0,0 +1,19 @@
+require 'securerandom'
+require 'openssl'
+require 'jwt'
+
+module Nexmo
+  module JWT
+    def self.auth_header(payload, private_key)
+      payload[:iat] = iat = Time.now.to_i
+      payload[:exp] = iat + 60
+      payload[:jti] = SecureRandom.uuid
+
+      private_key = OpenSSL::PKey::RSA.new(private_key) unless private_key.respond_to?(:sign)
+
+      token = ::JWT.encode(payload, private_key, 'RS256')
+
+      "Bearer #{token}"
+    end
+  end
+end
diff --git a/lib/nexmo/params.rb b/lib/nexmo/params.rb
new file mode 100644
index 00000000..63d75dd9
--- /dev/null
+++ b/lib/nexmo/params.rb
@@ -0,0 +1,13 @@
+require 'cgi'
+
+module Nexmo
+  module Params
+    def self.encode(params)
+      params.flat_map { |k, vs| Array(vs).map { |v| "#{escape(k)}=#{escape(v)}" } }.join('&')
+    end
+
+    def self.escape(component)
+      CGI.escape(component.to_s)
+    end
+  end
+end
diff --git a/lib/nexmo/signature.rb b/lib/nexmo/signature.rb
new file mode 100644
index 00000000..31c5a5d0
--- /dev/null
+++ b/lib/nexmo/signature.rb
@@ -0,0 +1,26 @@
+require 'digest/md5'
+require 'jwt'
+
+module Nexmo
+  module Signature
+    def self.check(params, secret)
+      params = params.dup
+
+      signature = params.delete(:sig)
+
+      ::JWT.secure_compare(signature, digest(params, secret))
+    end
+
+    def self.digest(params, secret)
+      md5 = Digest::MD5.new
+
+      params.sort.each do |k, v|
+        md5.update("&#{k}=#{v}")
+      end
+
+      md5.update(secret)
+
+      md5.hexdigest
+    end
+  end
+end
diff --git a/nexmo.gemspec b/nexmo.gemspec
index 0013c0d8..f428097c 100644
--- a/nexmo.gemspec
+++ b/nexmo.gemspec
@@ -12,6 +12,7 @@ Gem::Specification.new do |s|
   s.summary = 'This is the Ruby client library for Nexmo\'s API. To use it you\'ll need a Nexmo account. Sign up for free at https://www.nexmo.com'
   s.files = Dir.glob('{lib,spec}/**/*') + %w(LICENSE.txt README.md nexmo.gemspec)
   s.required_ruby_version = '>= 1.9.3'
+  s.add_dependency('jwt')
   s.add_development_dependency('rake', '~> 10.1')
   s.add_development_dependency('webmock', '~> 1.18')
   s.add_development_dependency('minitest', '~> 5.0')
diff --git a/spec/nexmo_spec.rb b/spec/nexmo_spec.rb
index 5f8f5ee7..81aaf5fb 100644
--- a/spec/nexmo_spec.rb
+++ b/spec/nexmo_spec.rb
@@ -8,6 +8,10 @@
 
     @api_secret = 'api_secret_xxx'
 
+    @application_id = 'nexmo-application-id'
+
+    @private_key = File.read('test/private_key.txt')
+
     @base_url = 'https://rest.nexmo.com'
 
     @api_base_url = 'https://api.nexmo.com'
@@ -18,16 +22,14 @@
 
     @response_object = {'key' => 'value'}
 
-    @example_message_hash = {from: 'ruby', to: 'number', text: 'Hey!'}
-
-    @client = Nexmo::Client.new(key: @api_key, secret: @api_secret)
+    @client = Nexmo::Client.new(key: @api_key, secret: @api_secret, application_id: @application_id, private_key: @private_key)
   end
 
   describe 'send_message method' do
     it 'posts to the sms resource and returns the response object' do
       expect_post "#@base_url/sms/json", "from=ruby&to=number&text=Hey!&api_key=#@api_key&api_secret=#@api_secret"
 
-      @client.send_message(@example_message_hash).must_equal(@response_object)
+      @client.send_message(from: 'ruby', to: 'number', text: 'Hey!').must_equal(@response_object)
     end
   end
 
@@ -161,7 +163,7 @@
     it 'posts to the ussd resource and returns the response object' do
       expect_post "#@base_url/ussd/json", "api_key=#@api_key&api_secret=#@api_secret&from=MyCompany20&to=447525856424&text=Hello"
 
-      @client.send_ussd_push_message(from: 'MyCompany20', to: '447525856424', text: 'Hello')
+      @client.send_ussd_push_message(from: 'MyCompany20', to: '447525856424', text: 'Hello').must_equal(@response_object)
     end
   end
 
@@ -169,7 +171,7 @@
     it 'posts to the ussd prompt resource and returns the response object' do
       expect_post "#@base_url/ussd-prompt/json", "api_key=#@api_key&api_secret=#@api_secret&from=virtual-number&to=447525856424&text=Hello"
 
-      @client.send_ussd_prompt_message(from: 'virtual-number', to: '447525856424', text: 'Hello')
+      @client.send_ussd_prompt_message(from: 'virtual-number', to: '447525856424', text: 'Hello').must_equal(@response_object)
     end
   end
 
@@ -177,7 +179,7 @@
     it 'posts to the short code two factor authentication resource and returns the response object' do
       expect_post "#@base_url/sc/us/2fa/json", "api_key=#@api_key&api_secret=#@api_secret&to=16365553226&pin=1234"
 
-      @client.send_2fa_message(to: '16365553226', pin: 1234)
+      @client.send_2fa_message(to: '16365553226', pin: 1234).must_equal(@response_object)
     end
   end
 
@@ -185,7 +187,7 @@
     it 'posts to the short code alert resource and returns the response object' do
       expect_post "#@base_url/sc/us/alert/json", "api_key=#@api_key&api_secret=#@api_secret&to=16365553226&server=host&link=http://example.com/"
 
-      @client.send_event_alert_message(to: '16365553226', server: 'host', link: 'http://example.com/')
+      @client.send_event_alert_message(to: '16365553226', server: 'host', link: 'http://example.com/').must_equal(@response_object)
     end
   end
 
@@ -193,7 +195,7 @@
     it 'posts to the short code marketing resource and returns the response object' do
       expect_post "#@base_url/sc/us/marketing/json", "api_key=#@api_key&api_secret=#@api_secret&from=666&to=16365553226&keyword=NEXMO&text=Hello"
 
-      @client.send_marketing_message(from: '666', to: '16365553226', keyword: 'NEXMO', text: 'Hello')
+      @client.send_marketing_message(from: '666', to: '16365553226', keyword: 'NEXMO', text: 'Hello').must_equal(@response_object)
     end
   end
 
@@ -201,7 +203,7 @@
     it 'fetches the short code alert opt-in query resource and returns the response object' do
       expect_get "#@base_url/sc/us/alert/opt-in/query/json?api_key=#@api_key&api_secret=#@api_secret"
 
-      @client.get_event_alert_numbers
+      @client.get_event_alert_numbers.must_equal(@response_object)
     end
   end
 
@@ -209,7 +211,7 @@
     it 'posts to the short code alert opt-in manage resource and returns the response object' do
       expect_post "#@base_url/sc/us/alert/opt-in/manage/json", "api_key=#@api_key&api_secret=#@api_secret&msisdn=441632960960"
 
-      @client.resubscribe_event_alert_number(msisdn: '441632960960')
+      @client.resubscribe_event_alert_number(msisdn: '441632960960').must_equal(@response_object)
     end
   end
 
@@ -217,7 +219,7 @@
     it 'posts to the sns resource and returns the response object' do
       expect_post "#@sns_base_url/sns/json", "api_key=#@api_key&api_secret=#@api_secret&cmd=publish&message=Hello&topic=arn&from=MyCompany20"
 
-      @client.sns_publish('Hello', topic: 'arn', from: 'MyCompany20')
+      @client.sns_publish('Hello', topic: 'arn', from: 'MyCompany20').must_equal(@response_object)
     end
   end
 
@@ -225,7 +227,7 @@
     it 'posts to the sns resource and returns the response object' do
       expect_post "#@sns_base_url/sns/json", "api_key=#@api_key&api_secret=#@api_secret&cmd=subscribe&to=447525856424&topic=arn"
 
-      @client.sns_subscribe('447525856424', topic: 'arn')
+      @client.sns_subscribe('447525856424', topic: 'arn').must_equal(@response_object)
     end
   end
 
@@ -233,7 +235,9 @@
     it 'posts to the call resource and returns the response object' do
       expect_post "#@base_url/call/json", "api_key=#@api_key&api_secret=#@api_secret&to=16365553226&answer_url=http://example.com/answer"
 
-      @client.initiate_call(to: '16365553226', answer_url: 'http://example.com/answer')
+      Kernel.stub :warn, proc { |message| message.must_match(/initiate_call is deprecated/) } do
+        @client.initiate_call(to: '16365553226', answer_url: 'http://example.com/answer').must_equal(@response_object)
+      end
     end
   end
 
@@ -241,7 +245,9 @@
     it 'posts to the tts resource and returns the response object' do
       expect_post "#@api_base_url/tts/json", "api_key=#@api_key&api_secret=#@api_secret&to=16365553226&text=Hello"
 
-      @client.initiate_tts_call(to: '16365553226', text: 'Hello')
+      Kernel.stub :warn, proc { |message| message.must_match(/initiate_tts_call is deprecated/) } do
+        @client.initiate_tts_call(to: '16365553226', text: 'Hello').must_equal(@response_object)
+      end
     end
   end
 
@@ -249,7 +255,9 @@
     it 'posts to the tts prompt resource and returns the response object' do
       expect_post "#@api_base_url/tts-prompt/json", "api_key=#@api_key&api_secret=#@api_secret&to=16365553226&text=Hello&max_digits=4&bye_text=Goodbye"
 
-      @client.initiate_tts_prompt_call(to: '16365553226', text: 'Hello', max_digits: 4, bye_text: 'Goodbye')
+      Kernel.stub :warn, proc { |message| message.must_match(/initiate_tts_prompt_call is deprecated/) } do
+        @client.initiate_tts_prompt_call(to: '16365553226', text: 'Hello', max_digits: 4, bye_text: 'Goodbye').must_equal(@response_object)
+      end
     end
   end
 
@@ -257,7 +265,7 @@
     it 'posts to the verify json resource and returns the response object' do
       expect_post "#@api_base_url/verify/json", "api_key=#@api_key&api_secret=#@api_secret&number=447525856424&brand=MyApp"
 
-      @client.start_verification(number: '447525856424', brand: 'MyApp')
+      @client.start_verification(number: '447525856424', brand: 'MyApp').must_equal(@response_object)
     end
   end
 
@@ -266,7 +274,7 @@
       expect_post "#@api_base_url/verify/json", "api_key=#@api_key&api_secret=#@api_secret&number=447525856424&brand=MyApp"
 
       Kernel.stub :warn, proc { |message| message.must_match(/send_verification_request is deprecated/) } do
-        @client.send_verification_request(number: '447525856424', brand: 'MyApp')
+        @client.send_verification_request(number: '447525856424', brand: 'MyApp').must_equal(@response_object)
       end
     end
   end
@@ -275,7 +283,7 @@
     it 'posts to the verify check resource and returns the response object' do
       expect_post "#@api_base_url/verify/check/json", "api_key=#@api_key&api_secret=#@api_secret&request_id=8g88g88eg8g8gg9g90&code=123445"
 
-      @client.check_verification('8g88g88eg8g8gg9g90', code: '123445')
+      @client.check_verification('8g88g88eg8g8gg9g90', code: '123445').must_equal(@response_object)
     end
   end
 
@@ -284,7 +292,7 @@
       expect_post "#@api_base_url/verify/check/json", "api_key=#@api_key&api_secret=#@api_secret&request_id=8g88g88eg8g8gg9g90&code=123445"
 
       Kernel.stub :warn, proc { |message| message.must_match(/check_verification_request is deprecated/) } do
-        @client.check_verification_request(request_id: '8g88g88eg8g8gg9g90', code: '123445')
+        @client.check_verification_request(request_id: '8g88g88eg8g8gg9g90', code: '123445').must_equal(@response_object)
       end
     end
   end
@@ -293,7 +301,7 @@
     it 'fetches the verify search resource with the given request id and returns the response object' do
       expect_get "#@api_base_url/verify/search/json?api_key=#@api_key&api_secret=#@api_secret&request_id=8g88g88eg8g8gg9g90"
 
-      @client.get_verification('8g88g88eg8g8gg9g90')
+      @client.get_verification('8g88g88eg8g8gg9g90').must_equal(@response_object)
     end
   end
 
@@ -302,7 +310,7 @@
       expect_get "#@api_base_url/verify/search/json?api_key=#@api_key&api_secret=#@api_secret&request_id=8g88g88eg8g8gg9g90"
 
       Kernel.stub :warn, proc { |message| message.must_match(/get_verification_request is deprecated/) } do
-        @client.get_verification_request('8g88g88eg8g8gg9g90')
+        @client.get_verification_request('8g88g88eg8g8gg9g90').must_equal(@response_object)
       end
     end
   end
@@ -311,7 +319,7 @@
     it 'posts to the verify control resource and returns the response object' do
       expect_post "#@api_base_url/verify/control/json", "api_key=#@api_key&api_secret=#@api_secret&request_id=8g88g88eg8g8gg9g90&cmd=cancel"
 
-      @client.cancel_verification('8g88g88eg8g8gg9g90')
+      @client.cancel_verification('8g88g88eg8g8gg9g90').must_equal(@response_object)
     end
   end
 
@@ -319,7 +327,7 @@
     it 'posts to the verify control resource and returns the response object' do
       expect_post "#@api_base_url/verify/control/json", "api_key=#@api_key&api_secret=#@api_secret&request_id=8g88g88eg8g8gg9g90&cmd=trigger_next_event"
 
-      @client.trigger_next_verification_event('8g88g88eg8g8gg9g90')
+      @client.trigger_next_verification_event('8g88g88eg8g8gg9g90').must_equal(@response_object)
     end
   end
 
@@ -328,7 +336,7 @@
       expect_post "#@api_base_url/verify/control/json", "api_key=#@api_key&api_secret=#@api_secret&request_id=8g88g88eg8g8gg9g90&cmd=cancel"
 
       Kernel.stub :warn, proc { |message| message.must_match(/control_verification_request is deprecated/) } do
-        @client.control_verification_request(request_id: '8g88g88eg8g8gg9g90', cmd: 'cancel')
+        @client.control_verification_request(request_id: '8g88g88eg8g8gg9g90', cmd: 'cancel').must_equal(@response_object)
       end
     end
   end
@@ -337,7 +345,7 @@
     it 'fetches the number format resource and returns the response object' do
       expect_get "#@api_base_url/number/format/json?api_key=#@api_key&api_secret=#@api_secret&number=447525856424"
 
-      @client.get_basic_number_insight(number: '447525856424')
+      @client.get_basic_number_insight(number: '447525856424').must_equal(@response_object)
     end
   end
 
@@ -345,7 +353,7 @@
     it 'fetches the number lookup resource and returns the response object' do
       expect_get "#@api_base_url/number/lookup/json?api_key=#@api_key&api_secret=#@api_secret&number=447525856424"
 
-      @client.get_number_insight(number: '447525856424')
+      @client.get_number_insight(number: '447525856424').must_equal(@response_object)
     end
   end
 
@@ -353,34 +361,162 @@
     it 'posts to the number insight resource and returns the response object' do
       expect_post "#@base_url/ni/json", "api_key=#@api_key&api_secret=#@api_secret&number=447525856424&callback=https://example.com"
 
-      @client.request_number_insight(number: '447525856424', callback: 'https://example.com')
+      @client.request_number_insight(number: '447525856424', callback: 'https://example.com').must_equal(@response_object)
+    end
+  end
+
+  describe 'get_applications method' do
+    it 'fetches the applications resource and returns the response object' do
+      expect_get "#@api_base_url/v1/applications?api_key=#@api_key&api_secret=#@api_secret"
+
+      @client.get_applications.must_equal(@response_object)
+    end
+  end
+
+  describe 'get_application method' do
+    it 'fetches the application resource with the given id and returns the response object' do
+      expect_get "#@api_base_url/v1/applications/xx-xx-xx-xx?api_key=#@api_key&api_secret=#@api_secret"
+
+      @client.get_application('xx-xx-xx-xx').must_equal(@response_object)
+    end
+  end
+
+  describe 'create_application method' do
+    it 'posts to the applications resource and returns the response object' do
+      expect_post "#@api_base_url/v1/applications", "api_key=#@api_key&api_secret=#@api_secret&name=Example+App&type=voice"
+
+      @client.create_application(name: 'Example App', type: 'voice')
+    end
+  end
+
+  describe 'update_application method' do
+    it 'puts to the application resource with the given id and returns the response object' do
+      expect_put "#@api_base_url/v1/applications/xx-xx-xx-xx", "api_key=#@api_key&api_secret=#@api_secret&answer_url=https%3A%2F%2Fexample.com%2Fncco"
+
+      @client.update_application('xx-xx-xx-xx', answer_url: 'https://example.com/ncco')
+    end
+  end
+
+  describe 'delete_application method' do
+    it 'deletes the application resource with the given id' do
+      expect_delete "#@api_base_url/v1/applications/xx-xx-xx-xx?api_key=#@api_key&api_secret=#@api_secret"
+
+      @client.delete_application('xx-xx-xx-xx')
+    end
+  end
+
+  describe 'create_call method' do
+    it 'posts to the calls resource and returns the response object' do
+      params = {
+        to: [{type: 'phone', number: '14843331234'}],
+        from: {type: 'phone', number: '14843335555'},
+        answer_url: ['https://example.com/answer']
+      }
+
+      expect :post, "#@api_base_url/v1/calls", params
+
+      @client.create_call(params).must_equal(@response_object)
+    end
+  end
+
+  describe 'get_calls method' do
+    it 'fetches the calls resource and returns the response object' do
+      expect :get, "#@api_base_url/v1/calls?status=completed"
+
+      @client.get_calls(status: 'completed').must_equal(@response_object)
+    end
+  end
+
+  describe 'get_call method' do
+    it 'fetches the call resource with the given uuid and returns the response object' do
+      expect :get, "#@api_base_url/v1/calls/xx-xx-xx-xx"
+
+      @client.get_call('xx-xx-xx-xx').must_equal(@response_object)
+    end
+  end
+
+  describe 'update_call method' do
+    it 'puts to the call resource with the given uuid and returns the response object' do
+      expect :put, "#@api_base_url/v1/calls/xx-xx-xx-xx", {action: 'hangup'}
+
+      @client.update_call('xx-xx-xx-xx', action: 'hangup').must_equal(@response_object)
+    end
+  end
+
+  describe 'send_audio method' do
+    it 'puts to the call stream resource with the given uuid and returns the response object' do
+      expect :put, "#@api_base_url/v1/calls/xx-xx-xx-xx/stream", {stream_url: 'http://example.com/audio.mp3'}
+
+      @client.send_audio('xx-xx-xx-xx', stream_url: 'http://example.com/audio.mp3').must_equal(@response_object)
+    end
+  end
+
+  describe 'stop_audio method' do
+    it 'deletes the call stream resource with the given uuid' do
+      expect :delete, "#@api_base_url/v1/calls/xx-xx-xx-xx/stream"
+
+      @client.stop_audio('xx-xx-xx-xx')
+    end
+  end
+
+  describe 'send_speech method' do
+    it 'puts to the call talk resource with the given uuid and returns the response object' do
+      expect :put, "#@api_base_url/v1/calls/xx-xx-xx-xx/talk", {text: 'Hello'}
+
+      @client.send_speech('xx-xx-xx-xx', text: 'Hello').must_equal(@response_object)
+    end
+  end
+
+  describe 'stop_speech method' do
+    it 'deletes the call talk resource with the given uuid' do
+      expect :delete, "#@api_base_url/v1/calls/xx-xx-xx-xx/talk"
+
+      @client.stop_speech('xx-xx-xx-xx')
+    end
+  end
+
+  describe 'send_dtmf method' do
+    it 'puts to the call dtmf resource with the given uuid and returns the response object' do
+      expect :put, "#@api_base_url/v1/calls/xx-xx-xx-xx/dtmf", {digits: '1234'}
+
+      @client.send_dtmf('xx-xx-xx-xx', digits: '1234').must_equal(@response_object)
+    end
+  end
+
+  describe 'check_signature method' do
+    it 'returns true if the signature in the given params is correct' do
+      params = {'a': '1', 'b': '2', 'timestamp': '1461605396', 'sig': '6af838ef94998832dbfc29020b564830'}
+
+      client = Nexmo::Client.new(key: @api_key, secret: @api_secret, signature_secret: 'secret')
+
+      client.check_signature(params).must_equal(true)
     end
   end
 
   it 'raises an authentication error exception if the response code is 401' do
-    stub_request(:post, "#@base_url/sms/json").to_return(status: 401)
+    stub_request(:get, /#{@base_url}/).to_return(status: 401)
 
-    proc { @client.send_message(@example_message_hash) }.must_raise(Nexmo::AuthenticationError)
+    proc { @client.get_balance }.must_raise(Nexmo::AuthenticationError)
   end
 
   it 'raises a client error exception if the response code is 4xx' do
-    stub_request(:post, "#@base_url/sms/json").to_return(status: 400)
+    stub_request(:get, /#{@base_url}/).to_return(status: 400)
 
-    proc { @client.send_message(@example_message_hash) }.must_raise(Nexmo::ClientError)
+    proc { @client.get_balance }.must_raise(Nexmo::ClientError)
   end
 
   it 'raises a server error exception if the response code is 5xx' do
-    stub_request(:post, "#@base_url/sms/json").to_return(status: 500)
+    stub_request(:get, /#{@base_url}/).to_return(status: 500)
 
-    proc { @client.send_message(@example_message_hash) }.must_raise(Nexmo::ServerError)
+    proc { @client.get_balance }.must_raise(Nexmo::ServerError)
   end
 
   it 'includes a user-agent header with the library version number and ruby version number' do
     headers = {'User-Agent' => "ruby-nexmo/#{Nexmo::VERSION}/#{RUBY_VERSION}"}
 
-    stub_request(:post, "#@base_url/sms/json").with(headers: headers).to_return(@response_body)
+    stub_request(:get, /#{@base_url}/).with(headers: headers).to_return(@response_body)
 
-    @client.send_message(@example_message_hash)
+    @client.get_balance
   end
 
   it 'provides options for application name and version to be included in the user-agent header' do
@@ -388,11 +524,11 @@
 
     headers = {'User-Agent' => "ruby-nexmo/#{Nexmo::VERSION}/#{RUBY_VERSION}/#{app_name}/#{app_version}"}
 
-    stub_request(:post, "#@base_url/sms/json").with(headers: headers).to_return(@response_body)
+    stub_request(:get, /#{@base_url}/).with(headers: headers).to_return(@response_body)
 
     @client = Nexmo::Client.new(key: @api_key, secret: @api_secret, app_name: app_name, app_version: app_version)
 
-    @client.send_message(@example_message_hash)
+    @client.get_balance
   end
 
   it 'provides an option for specifying a different hostname to connect to' do
@@ -413,6 +549,22 @@
 
   private
 
+  def expect(method_symbol, url, body = nil)
+    headers = {'Authorization' => /\ABearer (.+)\.(.+)\.(.+)\z/}
+
+    @request = stub_request(method_symbol, url)
+
+    if method_symbol == :delete
+      @request.with(headers: headers).to_return(status: 204)
+    elsif body.nil?
+      @request.with(headers: headers).to_return(@response_body)
+    else
+      headers['Content-Type'] = 'application/json'
+
+      @request.with(headers: headers, body: body).to_return(@response_body)
+    end
+  end
+
   def expect_get(url)
     @request = stub_request(:get, url).to_return(@response_body)
   end
@@ -425,6 +577,18 @@ def expect_post(url, data)
     @request = stub_request(:post, url).with(body: body, headers: headers).to_return(@response_body)
   end
 
+  def expect_put(url, data)
+    body = WebMock::Util::QueryMapper.query_to_values(data)
+
+    headers = {'Content-Type' => 'application/x-www-form-urlencoded'}
+
+    @request = stub_request(:put, url).with(body: body, headers: headers).to_return(@response_body)
+  end
+
+  def expect_delete(url)
+    @request = stub_request(:delete, url).to_return(status: 204)
+  end
+
   after do
     assert_requested(@request) if defined?(@request)
   end
diff --git a/test/private_key.txt b/test/private_key.txt
new file mode 100644
index 00000000..163ff367
--- /dev/null
+++ b/test/private_key.txt
@@ -0,0 +1,28 @@
+-----BEGIN PRIVATE KEY-----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+-----END PRIVATE KEY-----
diff --git a/test/public_key.txt b/test/public_key.txt
new file mode 100644
index 00000000..a1715089
--- /dev/null
+++ b/test/public_key.txt
@@ -0,0 +1,9 @@
+-----BEGIN PUBLIC KEY-----
+MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA0HQB6iR7P2vkWtrm70nd
+b8/2lpSfQapzFLQe4Lk5coIHRDQG5XiJM3qeplB3qQyXUIfEL+s0t5aVHitFJA36
+9fxb7L8bqxsP2GD2oFBIT/x8TG7Nq50E4gHVjk/lMfbzwAaMjWL2QfdMTSFYQQ0V
+oJM9Rz0AUTYxXJtzTqJfN4eVMKeWK6Bk1sfq6ZiIkYUI95r+pbpNdNnfeeLpaT6c
+3GFiiKSTXXJSaxJAWWoIQ2UzqW7+/anfnbPQFadY/IvXBv6MASabCVsX8ErTA6TX
+hGaqKXkFpgNdtbEhLMaQGyieQwOxf5ZnJMe+LLpSh19Xw1k++nEYZaGhEFZhE3Y9
+FQIDAQAB
+-----END PUBLIC KEY-----