diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 969ef2b..eeaf9fa 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -28,6 +28,7 @@ jobs:
     - uses: actions/setup-ruby@v1
       with:
         ruby-version: ${{ matrix.ruby }}
+    - run: gem install bundler
     - run: bundle
     - run: sleep 10
     - run: bundle exec rspec
diff --git a/.rubocop.yml b/.rubocop.yml
index 954b518..30cea9e 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -1,6 +1,7 @@
 AllCops:
   NewCops: enable
-  TargetRubyVersion: 2.4
+  TargetRubyVersion: 2.5
+  SuggestExtensions: false
 
 Layout/EmptyLineBetweenDefs:
   EmptyLineBetweenClassDefs: false
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 95237c9..56f2a7e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,12 @@
 
 # CHANGELOG
 
+## v3.3.0
+
+* Update httprb
+* Changed oj default options
+* Allow to set oj json options
+
 ## v3.2.1
 
 * Fix `refresh` having a empty body breaking in elasticsearch 7.11
diff --git a/README.md b/README.md
index 279637d..4dcb4b5 100644
--- a/README.md
+++ b/README.md
@@ -3,7 +3,7 @@
 
 **Full-Featured Elasticsearch Ruby Client with a Chainable DSL**
 
-[![Build Status](https://secure.travis-ci.org/mrkamel/search_flip.svg?branch=master)](http://travis-ci.org/mrkamel/search_flip)
+[![Build](https://github.com/mrkamel/search_flip/workflows/test/badge.svg)](https://github.com/mrkamel/search_flip/actions?query=workflow%3Atest+branch%3Amaster)
 [![Gem Version](https://badge.fury.io/rb/search_flip.svg)](http://badge.fury.io/rb/search_flip)
 
 Using SearchFlip it is dead-simple to create index classes that correspond to
@@ -51,8 +51,7 @@ CommentIndex.search("hello world").where(available: true).sort(id: "desc").aggre
 
 ```
 
-Finally, SearchFlip comes with a minimal set of dependencies (http-rb, hashie
-and oj only).
+Finally, SearchFlip comes with a minimal set of dependencies.
 
 ## Reference Docs
 
@@ -883,52 +882,46 @@ Thus, if your ORM supports `.find_each`, `#id` and `#where` you are already
 good to go. Otherwise, simply add your custom implementation of those methods
 that work with whatever ORM you use.
 
-## Date and Timestamps in JSON
+## JSON
 
-Elasticsearch requires dates and timestamps to have one of the formats listed
-here: [https://www.elastic.co/guide/en/elasticsearch/reference/current/mapping-date-format.html#strict-date-time](https://www.elastic.co/guide/en/elasticsearch/reference/current/mapping-date-format.html#strict-date-time).
-
-However, `JSON.generate` in ruby by default outputs something like:
+SearchFlip is using the [Oj gem](https://github.com/ohler55/oj) to generate
+JSON. More concretely, SearchFlip is using:
 
 ```ruby
-JSON.generate(time: Time.now.utc)
-# => "{\"time\":\"2018-02-22 18:19:33 UTC\"}"
+Oj.dump({ key: "value" }, mode: :custom, use_to_json: true, time_format: :xmlschema, bigdecimal_as_decimal: false)
 ```
 
-This format is not compatible with Elasticsearch by default. If you're on
-Rails, ActiveSupport adds its own `#to_json` methods to `Time`, `Date`, etc.
-However, ActiveSupport checks whether they are used in combination with
-`JSON.generate` or not and adapt:
+The `use_to_json` option is used for maximum compatibility, most importantly
+when using rails `ActiveSupport::TimeWithZone` timestamps, which `oj` can not
+serialize natively. However, `use_to_json` adds performance overhead. You can
+change the json options via:
 
 ```ruby
-Time.now.utc.to_json
-=> "\"2018-02-22T18:18:22.088Z\""
-
-JSON.generate(time: Time.now.utc)
-=> "{\"time\":\"2018-02-22 18:18:59 UTC\"}"
+SearchFlip::Config[:json_options] = {
+  mode: :custom,
+  use_to_json: false,
+  time_format: :xmlschema,
+  bigdecimal_as_decimal: false
+}
 ```
 
-SearchFlip is using the [Oj gem](https://github.com/ohler55/oj) to generate
-JSON. More concretely, SearchFlip is using:
+However, you then have to convert timestamps manually for indexation via e.g.:
 
 ```ruby
-Oj.dump({ key: "value" }, mode: :custom, use_to_json: true)
-```
+class MyIndex
+  # ...
 
-This mitigates the issues if you're on Rails:
+  def self.serialize(model)
+    {
+      # ...
 
-```ruby
-Oj.dump(Time.now, mode: :custom, use_to_json: true)
-# => "\"2018-02-22T18:21:21.064Z\""
+      created_at: model.created_at.to_time
+    }
+  end
+end
 ```
 
-However, if you're not on Rails, you need to add `#to_json` methods to `Time`,
-`Date` and `DateTime` to get proper serialization. You can either add them on
-your own, via other libraries or by simply using:
-
-```ruby
-require "search_flip/to_json"
-```
+Please check out the oj docs for more details.
 
 ## Feature Support
 
diff --git a/lib/search_flip.rb b/lib/search_flip.rb
index 6f2c9da..f1ad4df 100644
--- a/lib/search_flip.rb
+++ b/lib/search_flip.rb
@@ -3,6 +3,7 @@
 require "http"
 require "hashie"
 require "thread"
+require "json"
 require "oj"
 require "set"
 
diff --git a/lib/search_flip/bulk.rb b/lib/search_flip/bulk.rb
index f6eff9f..11c6cc8 100644
--- a/lib/search_flip/bulk.rb
+++ b/lib/search_flip/bulk.rb
@@ -143,7 +143,7 @@ def upload
 
       return if options[:raise] == false
 
-      parsed_response = response.parse
+      parsed_response = SearchFlip::JSON.parse(response.to_s)
 
       return unless parsed_response["errors"]
 
diff --git a/lib/search_flip/config.rb b/lib/search_flip/config.rb
index f56fef2..fcadcdb 100644
--- a/lib/search_flip/config.rb
+++ b/lib/search_flip/config.rb
@@ -5,6 +5,12 @@ module SearchFlip
     bulk_limit: 1_000,
     bulk_max_mb: 100,
     auto_refresh: false,
-    instrumenter: NullInstrumenter.new
+    instrumenter: NullInstrumenter.new,
+    json_options: {
+      mode: :custom,
+      use_to_json: true,
+      time_format: :xmlschema,
+      bigdecimal_as_decimal: false
+    }
   }
 end
diff --git a/lib/search_flip/connection.rb b/lib/search_flip/connection.rb
index 5983b9a..9effae0 100644
--- a/lib/search_flip/connection.rb
+++ b/lib/search_flip/connection.rb
@@ -28,7 +28,11 @@ def initialize(options = {})
 
     def version
       @version_mutex.synchronize do
-        @version ||= http_client.headers(accept: "application/json").get("#{base_url}/").parse["version"]["number"]
+        @version ||= begin
+          response = http_client.headers(accept: "application/json").get("#{base_url}/")
+
+          SearchFlip::JSON.parse(response.to_s)["version"]["number"]
+        end
       end
     end
 
@@ -40,7 +44,9 @@ def version
     # @return [Hash] The raw response
 
     def cluster_health
-      http_client.headers(accept: "application/json").get("#{base_url}/_cluster/health").parse
+      response = http_client.headers(accept: "application/json").get("#{base_url}/_cluster/health")
+
+      SearchFlip::JSON.parse(response.to_s)
     end
 
     # Uses the Elasticsearch Multi Search API to execute multiple search requests
@@ -71,7 +77,7 @@ def msearch(criterias)
           .headers(accept: "application/json", content_type: "application/x-ndjson")
           .post("#{base_url}/_msearch", body: payload)
 
-      raw_response.parse["responses"].map.with_index do |response, index|
+      SearchFlip::JSON.parse(raw_response.to_s)["responses"].map.with_index do |response, index|
         SearchFlip::Response.new(criterias[index], response)
       end
     end
@@ -90,10 +96,11 @@ def msearch(criterias)
     # @return [Hash] The raw response
 
     def update_aliases(payload)
-      http_client
+      response = http_client
         .headers(accept: "application/json", content_type: "application/json")
         .post("#{base_url}/_aliases", body: SearchFlip::JSON.generate(payload))
-        .parse
+
+      SearchFlip::JSON.parse(response.to_s)
     end
 
     # Sends an analyze request to Elasticsearch. Raises
@@ -105,10 +112,11 @@ def update_aliases(payload)
     # @return [Hash] The raw response
 
     def analyze(request, params = {})
-      http_client
+      response = http_client
         .headers(accept: "application/json")
         .post("#{base_url}/_analyze", json: request, params: params)
-        .parse
+
+      SearchFlip::JSON.parse(response.to_s)
     end
 
     # Fetches information about the specified index aliases. Raises
@@ -124,10 +132,11 @@ def analyze(request, params = {})
     # @return [Hash] The raw response
 
     def get_aliases(index_name: "*", alias_name: "*")
-      http_client
+      response = http_client
         .headers(accept: "application/json", content_type: "application/json")
         .get("#{base_url}/#{index_name}/_alias/#{alias_name}")
-        .parse
+
+      SearchFlip::JSON.parse(response.to_s)
     end
 
     # Returns whether or not the associated Elasticsearch alias already
@@ -159,10 +168,11 @@ def alias_exists?(alias_name)
     # @return [Array] The raw response
 
     def get_indices(name = "*", params: {})
-      http_client
+      response = http_client
         .headers(accept: "application/json", content_type: "application/json")
         .get("#{base_url}/_cat/indices/#{name}", params: params)
-        .parse
+
+      SearchFlip::JSON.parse(response.to_s)
     end
 
     alias_method :cat_indices, :get_indices
@@ -259,10 +269,11 @@ def update_index_settings(index_name, index_settings)
     # @return [Hash] The index settings
 
     def get_index_settings(index_name)
-      http_client
+      response = http_client
         .headers(accept: "application/json")
         .get("#{index_url(index_name)}/_settings")
-        .parse
+
+      SearchFlip::JSON.parse(response.to_s)
     end
 
     # Sends a refresh request to Elasticsearch. Raises
@@ -310,7 +321,9 @@ def get_mapping(index_name, type_name: nil)
       url = type_name ? type_url(index_name, type_name) : index_url(index_name)
       params = type_name && version.to_f >= 6.7 ? { include_type_name: true } : {}
 
-      http_client.headers(accept: "application/json").get("#{url}/_mapping", params: params).parse
+      response = http_client.headers(accept: "application/json").get("#{url}/_mapping", params: params)
+
+      SearchFlip::JSON.parse(response.to_s)
     end
 
     # Deletes the specified index from Elasticsearch. Raises
diff --git a/lib/search_flip/criteria.rb b/lib/search_flip/criteria.rb
index cb7a55a..acf98bd 100644
--- a/lib/search_flip/criteria.rb
+++ b/lib/search_flip/criteria.rb
@@ -608,7 +608,7 @@ def execute!
           http_request.post("#{target.type_url}/_search", params: request_params, json: request)
         end
 
-      SearchFlip::Response.new(self, http_response.parse)
+      SearchFlip::Response.new(self, SearchFlip::JSON.parse(http_response.to_s))
     rescue SearchFlip::ConnectionError, SearchFlip::ResponseError => e
       raise e unless failsafe_value
 
diff --git a/lib/search_flip/index.rb b/lib/search_flip/index.rb
index de7c084..baf5c01 100644
--- a/lib/search_flip/index.rb
+++ b/lib/search_flip/index.rb
@@ -455,7 +455,9 @@ def include_type_name?
       # @return [Hash] The specified document
 
       def get(id, params = {})
-        connection.http_client.headers(accept: "application/json").get("#{type_url}/#{id}", params: params).parse
+        response = connection.http_client.headers(accept: "application/json").get("#{type_url}/#{id}", params: params)
+
+        SearchFlip::JSON.parse(response.to_s)
       end
 
       # Retrieves the documents specified by ids from elasticsearch.
@@ -471,7 +473,9 @@ def get(id, params = {})
       # @return [Hash] The raw response
 
       def mget(request, params = {})
-        connection.http_client.headers(accept: "application/json").post("#{type_url}/_mget", json: request, params: params).parse
+        response = connection.http_client.headers(accept: "application/json").post("#{type_url}/_mget", json: request, params: params)
+
+        SearchFlip::JSON.parse(response.to_s)
       end
 
       # Sends an analyze request to Elasticsearch. Raises
@@ -483,7 +487,9 @@ def mget(request, params = {})
       # @return [Hash] The raw response
 
       def analyze(request, params = {})
-        connection.http_client.headers(accept: "application/json").post("#{index_url}/_analyze", json: request, params: params).parse
+        response = connection.http_client.headers(accept: "application/json").post("#{index_url}/_analyze", json: request, params: params)
+
+        SearchFlip::JSON.parse(response.to_s)
       end
 
       # Sends a index refresh request to Elasticsearch. Raises
diff --git a/lib/search_flip/json.rb b/lib/search_flip/json.rb
index 8fc077d..c168f1d 100644
--- a/lib/search_flip/json.rb
+++ b/lib/search_flip/json.rb
@@ -1,16 +1,11 @@
 module SearchFlip
   class JSON
-    @default_options = {
-      mode: :custom,
-      use_to_json: true
-    }
-
-    def self.default_options
-      @default_options
+    def self.generate(obj)
+      Oj.dump(obj, SearchFlip::Config[:json_options])
     end
 
-    def self.generate(obj)
-      Oj.dump(obj, default_options)
+    def self.parse(json)
+      ::JSON.parse(json)
     end
   end
 end
diff --git a/lib/search_flip/to_json.rb b/lib/search_flip/to_json.rb
index e79e135..0eeb558 100644
--- a/lib/search_flip/to_json.rb
+++ b/lib/search_flip/to_json.rb
@@ -1,29 +1 @@
-require "time"
-require "date"
-require "json"
-
-class Time
-  def to_json(*args)
-    iso8601(6).to_json
-  end
-end
-
-class Date
-  def to_json(*args)
-    iso8601.to_json
-  end
-end
-
-class DateTime
-  def to_json(*args)
-    iso8601(6).to_json
-  end
-end
-
-if defined?(ActiveSupport)
-  class ActiveSupport::TimeWithZone
-    def to_json(*args)
-      iso8601(6).to_json
-    end
-  end
-end
+warn "[DEPRECATION] Using search_flip/to_json is not neccessary anymore"
diff --git a/lib/search_flip/version.rb b/lib/search_flip/version.rb
index ef36b76..8c09e6d 100644
--- a/lib/search_flip/version.rb
+++ b/lib/search_flip/version.rb
@@ -1,3 +1,3 @@
 module SearchFlip
-  VERSION = "3.2.1"
+  VERSION = "3.3.0"
 end
diff --git a/search_flip.gemspec b/search_flip.gemspec
index 5991a19..fc0d469 100644
--- a/search_flip.gemspec
+++ b/search_flip.gemspec
@@ -37,6 +37,7 @@ Gem::Specification.new do |spec|
 
   spec.add_dependency "hashie"
   spec.add_dependency "http"
+  spec.add_dependency "json"
   spec.add_dependency "oj"
   spec.add_dependency "ruby2_keywords"
 end
diff --git a/spec/search_flip/json_spec.rb b/spec/search_flip/json_spec.rb
new file mode 100644
index 0000000..2c0e7ae
--- /dev/null
+++ b/spec/search_flip/json_spec.rb
@@ -0,0 +1,45 @@
+require File.expand_path("../spec_helper", __dir__)
+
+RSpec.describe SearchFlip::JSON do
+  describe ".generate" do
+    it "encodes timestamps correctly" do
+      Timecop.freeze "2020-06-01 12:00:00 UTC" do
+        expect(described_class.generate(timestamp: Time.now.utc)).to eq('{"timestamp":"2020-06-01T12:00:00.000Z"}')
+      end
+    end
+
+    it "encodes bigdecimals as string" do
+      expect(described_class.generate(value: BigDecimal(1))).to eq('{"value":"1.0"}')
+    end
+
+    it "delegates to Oj" do
+      allow(Oj).to receive(:dump)
+
+      payload = { key: "value" }
+
+      described_class.generate(payload)
+
+      expect(Oj).to have_received(:dump).with(payload, mode: :custom, use_to_json: true, time_format: :xmlschema, bigdecimal_as_decimal: false)
+    end
+
+    it "generates json" do
+      expect(described_class.generate(key: "value")).to eq('{"key":"value"}')
+    end
+  end
+
+  describe ".parse" do
+    it "returns the parsed json payload" do
+      expect(described_class.parse('{"key":"value"}')).to eq("key" => "value")
+    end
+
+    it "delegates to JSON" do
+      allow(JSON).to receive(:parse)
+
+      payload = '{"key":"value"}'
+
+      described_class.parse(payload)
+
+      expect(JSON).to have_received(:parse).with(payload)
+    end
+  end
+end
diff --git a/spec/search_flip/to_json_spec.rb b/spec/search_flip/to_json_spec.rb
deleted file mode 100644
index 86dec74..0000000
--- a/spec/search_flip/to_json_spec.rb
+++ /dev/null
@@ -1,28 +0,0 @@
-require File.expand_path("../spec_helper", __dir__)
-require "search_flip/to_json"
-
-RSpec.describe "to_json" do
-  it "uses the correct format for Time" do
-    Timecop.freeze Time.parse("2018-01-01 12:00:00 UTC") do
-      expect(Time.now.utc.to_json).to eq("\"2018-01-01T12:00:00.000000Z\"")
-    end
-  end
-
-  it "uses the correct format for Date" do
-    Timecop.freeze Time.parse("2018-01-01 12:00:00 UTC") do
-      expect(Date.today.to_json).to eq("\"2018-01-01\"")
-    end
-  end
-
-  it "uses the correct format for DateTime" do
-    Timecop.freeze Time.parse("2018-01-01 12:00:00 UTC") do
-      expect(Time.now.utc.to_json).to eq("\"2018-01-01T12:00:00.000000Z\"")
-    end
-  end
-
-  it "uses the correct format for TimeWithZone" do
-    Timecop.freeze Time.parse("2018-01-01 12:00:00 UTC") do
-      expect(Time.find_zone("UTC").now.to_json).to eq("\"2018-01-01T12:00:00.000000Z\"")
-    end
-  end
-end