diff --git a/Gemfile b/Gemfile
index b9de014..7ec4df3 100644
--- a/Gemfile
+++ b/Gemfile
@@ -8,9 +8,8 @@ gem 'fixer'
 gem 'newrelic_rpm'
 gem 'rake'
 gem 'sequel_pg'
-gem 'sinatra-jsonp'
+gem 'sinatra'
 gem 'unicorn'
-gem 'yajl-ruby'
 
 group :development do
   gem 'minitest'
diff --git a/Gemfile.lock b/Gemfile.lock
index 61074d7..3604a52 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -11,7 +11,6 @@ GEM
     minitest (5.8.4)
     minitest-around (0.3.2)
       minitest (~> 5.0)
-    multi_json (1.11.2)
     newrelic_rpm (3.15.1.316)
     oga (2.2)
       ast
@@ -41,15 +40,11 @@ GEM
       rack (~> 1.5)
       rack-protection (~> 1.4)
       tilt (>= 1.3, < 3)
-    sinatra-jsonp (0.4.4)
-      multi_json (~> 1.8)
-      sinatra (~> 1.0)
     slop (3.6.0)
     tilt (2.0.2)
     unicorn (5.1.0)
       kgio (~> 2.6)
       raindrops (~> 0.7)
-    yajl-ruby (1.2.1)
 
 PLATFORMS
   ruby
@@ -64,9 +59,8 @@ DEPENDENCIES
   rake
   sequel_pg
   shotgun
-  sinatra-jsonp
+  sinatra
   unicorn
-  yajl-ruby
 
 BUNDLED WITH
    1.11.2
diff --git a/config/app.rb b/config/app.rb
index 41193a0..a0ec39a 100644
--- a/config/app.rb
+++ b/config/app.rb
@@ -6,7 +6,7 @@ require 'pathname'
 # Encapsulates app configuration
 module App
   class << self
-    attr_reader :logger
+    attr_reader :logger, :version, :released_at
 
     def env
       ENV['RACK_ENV'] || 'development'
@@ -15,11 +15,9 @@ module App
     def root
       Pathname.pwd
     end
-
-    def version
-      `git rev-parse --short HEAD 2>/dev/null`.strip!
-    end
   end
 
   @logger = Logger.new(STDOUT)
+  @version = `git rev-parse --short HEAD 2>/dev/null`.strip!
+  @released_at = `git show -s --format=%ci HEAD`
 end
diff --git a/lib/api.rb b/lib/api.rb
index b3ac943..39a465f 100644
--- a/lib/api.rb
+++ b/lib/api.rb
@@ -1,8 +1,7 @@
 # frozen_string_literal: true
 
+require 'json'
 require 'sinatra'
-require 'sinatra/jsonp'
-require 'yajl'
 require 'quote'
 
 configure do
@@ -30,26 +29,31 @@ end
 helpers do
   def quote
     @quote ||= begin
-      ret = Quote.new(params).attributes
-      ret[:rates].keep_if { |k, _| symbols.include?(k) } if symbols
-
-      ret
+      Quote.new(params).attributes.tap do |quote|
+        quote[:rates].keep_if { |k, _| symbols.include?(k) } if symbols
+      end
     end
   rescue Quote::Invalid => ex
-    halt_with_message 422, ex.message
+    halt 422, JSON.generate(error: ex.message)
   end
 
   def symbols
-    return @symbols if defined?(@symbols)
-
-    @symbols = begin
-      ret = params.delete('symbols') || params.delete('currencies')
-      ret.split(',') if ret
+    @symbols ||= begin
+      params.values_at('symbols', 'currencies').first.tap do |symbols|
+        symbols.split(',') if symbols
+      end
     end
   end
 
-  def halt_with_message(status, message)
-    halt status, Yajl::Encoder.encode(error: message)
+  def jsonp(data)
+    callback = params.delete('callback')
+    if callback
+      content_type :js
+      "#{callback}(#{JSON.generate(data)})"
+    else
+      content_type :json
+      JSON.generate(data)
+    end
   end
 
   def enable_cross_origin
@@ -65,6 +69,7 @@ end
 
 get '/' do
   enable_cross_origin
+  last_modified App.released_at
   jsonp details: 'http://fixer.io', version: App.version
 end
 
@@ -81,5 +86,5 @@ get(/(?<date>\d{4}-\d{2}-\d{2})/) do
 end
 
 not_found do
-  halt_with_message 404, 'Not found'
+  halt 404, JSON.generate(error: 'Not found')
 end
diff --git a/spec/api_spec.rb b/spec/api_spec.rb
index fea9d0a..cdfa7a2 100644
--- a/spec/api_spec.rb
+++ b/spec/api_spec.rb
@@ -8,7 +8,7 @@ describe 'the API' do
   include Rack::Test::Methods
 
   let(:app)  { Sinatra::Application }
-  let(:json) { Yajl::Parser.new.parse last_response.body }
+  let(:json) { JSON.parse last_response.body }
   let(:headers) { last_response.headers }
 
   it 'describes itself' do
@@ -42,14 +42,11 @@ describe 'the API' do
     json['rates'].wont_be :empty?
   end
 
-  it 'returns a last modified header for latest quote' do
-    get '/latest'
-    headers['Last-Modified'].wont_be_nil
-  end
-
-  it 'returns a last modified header for historical quote' do
-    get '/2012-11-20'
-    headers['Last-Modified'].wont_be_nil
+  it 'returns a last modified header' do
+    %w(/ /latest /2012-11-20).each do |path|
+      get path
+      headers['Last-Modified'].wont_be_nil
+    end
   end
 
   it 'allows cross-origin requests' do
diff --git a/spec/edge_cases_spec.rb b/spec/edge_cases_spec.rb
index 08a5459..7e19789 100644
--- a/spec/edge_cases_spec.rb
+++ b/spec/edge_cases_spec.rb
@@ -6,31 +6,36 @@ describe 'the API' do
   include Rack::Test::Methods
 
   let(:app)  { Sinatra::Application }
-  let(:json) { Yajl::Parser.new.parse last_response.body }
+  let(:json) { JSON.parse last_response.body }
 
   it 'handles unfound pages' do
     get '/foo'
     last_response.status.must_equal 404
+    json.wont_be_empty
   end
 
   it 'will not process an invalid date' do
     get '/2010-31-01'
     last_response.must_be :unprocessable?
+    json.wont_be_empty
   end
 
   it 'will not process a date before 2000' do
     get '/1999-01-01'
     last_response.must_be :unprocessable?
+    json.wont_be_empty
   end
 
   it 'will not process an invalid base' do
     get '/latest?base=UAH'
     last_response.must_be :unprocessable?
+    json.wont_be_empty
   end
 
   it 'handles malformed queries' do
     get '/latest?base=USD?callback=?'
     last_response.must_be :unprocessable?
+    json.wont_be_empty
   end
 
   it 'returns fresh dates' do