diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
deleted file mode 100644
index cf7ef6c..0000000
--- a/.github/workflows/lint.yml
+++ /dev/null
@@ -1,30 +0,0 @@
-name: Lint
-on: [push, pull_request]
-jobs:
-  rubocop:
-    runs-on: ubuntu-latest
-    strategy:
-      fail-fast: true
-
-    steps:
-      - uses: actions/checkout@v2
-      - uses: ruby/setup-ruby@v1
-        with:
-          ruby-version: 2.6
-      - run: gem install bundler
-      - run: bundle install --jobs=$(nproc) --retry=$(nproc)
-      - run: bin/rubocop -P
-
-  reek:
-    runs-on: ubuntu-latest
-    strategy:
-      fail-fast: true
-
-    steps:
-      - uses: actions/checkout@v2
-      - uses: ruby/setup-ruby@v1
-        with:
-          ruby-version: 2.6
-      - run: gem install bundler
-      - run: bundle install --jobs=$(nproc) --retry=$(nproc)
-      - run: bin/reek .
diff --git a/.github/workflows/rspec.yml b/.github/workflows/rspec.yml
index b54afb7..943492d 100644
--- a/.github/workflows/rspec.yml
+++ b/.github/workflows/rspec.yml
@@ -2,23 +2,17 @@ name: RSpec
 on: [push, pull_request]
 jobs:
   tests:
-    env:
-      COV: true
-
     runs-on: ubuntu-latest
 
     strategy:
-      fail-fast: true
+      fail-fast: false
       matrix:
-        # ruby: [2.5, 2.6, 2.7, jruby, truffleruby]
-        ruby: [2.5, 2.6, 2.7]
+        ruby: ['3.3', '3.4']
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - uses: ruby/setup-ruby@v1
         with:
           ruby-version: ${{ matrix.ruby }}
-      - run: gem install bundler
-      - run: bundle install --jobs=$(nproc) --retry=$(nproc)
-      - run: bin/rspec
-
+          bundler-cache: true
+      - run: bundle exec rspec
diff --git a/active_campaign.gemspec b/active_campaign.gemspec
index 700cda6..006aaf4 100644
--- a/active_campaign.gemspec
+++ b/active_campaign.gemspec
@@ -29,7 +29,6 @@ Gem::Specification.new do |spec|
   spec.test_files    = spec.files.grep(%r{^(test|spec|features)/})
   spec.require_paths = ['lib']
 
-  spec.add_dependency 'activesupport',  '>= 4.0', '< 8.0'
-  spec.add_dependency 'faraday',        '>= 1.0', '< 3.0'
+  spec.add_dependency 'faraday',        '>= 1.2', '< 3.0'
   spec.add_dependency 'oj',             '>= 3.0', '< 4.0'
 end
diff --git a/lib/active_campaign.rb b/lib/active_campaign.rb
index 673e33f..b5d8ddb 100644
--- a/lib/active_campaign.rb
+++ b/lib/active_campaign.rb
@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 require 'faraday'
+require 'oj'
 
 require 'active_campaign/version'
 require 'active_campaign/errors'
diff --git a/lib/active_campaign/api.rb b/lib/active_campaign/api.rb
index 724c484..9a2de2d 100644
--- a/lib/active_campaign/api.rb
+++ b/lib/active_campaign/api.rb
@@ -40,7 +40,7 @@ def endpoints(*endpoints)
       def endpoint(endpoint)
         require "active_campaign/api/#{endpoint}"
 
-        class_eval { include API.const_get(endpoint.to_s.camelize) }
+        class_eval { include API.const_get(TransformHash.camelize(endpoint.to_s)) }
       rescue LoadError, NameError
         raise DependencyMissing, endpoint
       end
diff --git a/lib/active_campaign/faraday/middleware/request.rb b/lib/active_campaign/faraday/middleware/request.rb
index dec1dee..997b7a4 100644
--- a/lib/active_campaign/faraday/middleware/request.rb
+++ b/lib/active_campaign/faraday/middleware/request.rb
@@ -9,8 +9,6 @@ module Middleware
       # @author Mikael Henriksson <mikael@mhenrixon.com>
       #
       class Request < ::Faraday::Middleware
-        dependency 'oj'
-
         include TransformHash
 
         def initialize(app, headers)
diff --git a/lib/active_campaign/faraday/middleware/response.rb b/lib/active_campaign/faraday/middleware/response.rb
index bcd38f6..6b40559 100644
--- a/lib/active_campaign/faraday/middleware/response.rb
+++ b/lib/active_campaign/faraday/middleware/response.rb
@@ -12,9 +12,7 @@ module Middleware
       #
       # @author Mikael Henriksson <mikael@mhenrixon.com>
       #
-      class Response < ::Faraday::Response::Middleware
-        dependency 'oj'
-
+      class Response < ::Faraday::Middleware
         include TransformHash
 
         # Override this to modify the environment after the response has finished.
diff --git a/lib/active_campaign/transform_hash.rb b/lib/active_campaign/transform_hash.rb
index a7fae40..756d92a 100644
--- a/lib/active_campaign/transform_hash.rb
+++ b/lib/active_campaign/transform_hash.rb
@@ -1,7 +1,5 @@
 # frozen_string_literal: true
 
-require 'active_support/core_ext/string'
-
 module ActiveCampaign
   #
   # Utility module for manipulating hashes, arrays and values
@@ -35,7 +33,7 @@ def transform_keys(hash, *new_case)
     # @return [Symbol] the transformed key
     #
     def transform_key(key, *new_case)
-      key.to_s.public_send(*new_case).to_sym
+      inflect(key.to_s, *new_case).to_sym
     end
 
     #
@@ -68,5 +66,38 @@ def transform_array(collection, *new_case)
         end
       end
     end
+
+    #
+    # Changes the case of a string
+    #
+    # @param [String] string the string to change
+    # @param [Symbol] style `:underscore` or `:camelcase`
+    # @param [Symbol] first_letter `:upper` or `:lower`, only used by `:camelcase`
+    #
+    # @return [String]
+    #
+    def inflect(string, style, first_letter = :upper)
+      case style
+      when :underscore then underscore(string)
+      when :camelcase then camelize(string, first_letter)
+      else raise ArgumentError, "unknown case #{style.inspect}"
+      end
+    end
+
+    # The rules below are the ActiveSupport ones without acronyms or namespace (::) handling. They live here
+    # so an application's inflection config can't change the keys sent to the API.
+    def underscore(string)
+      return string unless /[A-Z-]/.match?(string)
+
+      string
+        .gsub(/([A-Z])(?=[A-Z][a-z])|([a-z\d])(?=[A-Z])/) { "#{Regexp.last_match(1) || Regexp.last_match(2)}_" }
+        .tr('-', '_')
+        .downcase
+    end
+
+    def camelize(string, first_letter = :upper)
+      head = first_letter == :lower ? string.sub(/\A\w/, &:downcase) : string.sub(/\A[a-z\d]*/, &:capitalize)
+      head.gsub(/_([a-z\d]*)/i) { Regexp.last_match(1).capitalize }
+    end
   end
 end
diff --git a/spec/lib/active_campaign/api/deal_stages_spec.rb b/spec/lib/active_campaign/api/deal_stages_spec.rb
index 7c2806c..64fc10f 100644
--- a/spec/lib/active_campaign/api/deal_stages_spec.rb
+++ b/spec/lib/active_campaign/api/deal_stages_spec.rb
@@ -8,10 +8,6 @@
 
     include_context 'with deal_stage params'
 
-    after do
-      client.delete_deal_stage(response.dig(:deal, :id))
-    end
-
     # rubocop:disable RSpec/ExampleLength
     it 'returns a deal_stage hash' do
       expect(response).to include_json(
diff --git a/spec/lib/active_campaign/api/fields_spec.rb b/spec/lib/active_campaign/api/fields_spec.rb
index 7393803..5819901 100644
--- a/spec/lib/active_campaign/api/fields_spec.rb
+++ b/spec/lib/active_campaign/api/fields_spec.rb
@@ -74,8 +74,7 @@
     end
 
     it 'makes the custom field irretrievable' do
-      show_response = client.show_field(field_id)
-      expect(show_response).not_to include_json(field: expected_field_response)
+      expect { client.show_field(field_id) }.to raise_error(ActiveCampaign::ResourceNotFound)
     end
   end
 
diff --git a/spec/lib/active_campaign/api/pipelines_spec.rb b/spec/lib/active_campaign/api/pipelines_spec.rb
index 91b337c..1122eae 100644
--- a/spec/lib/active_campaign/api/pipelines_spec.rb
+++ b/spec/lib/active_campaign/api/pipelines_spec.rb
@@ -18,10 +18,6 @@
 
     include_context 'with pipeline params'
 
-    after do
-      client.delete_pipeline(response.dig(:pipeline, :id))
-    end
-
     it 'returns a pipeline hash' do
       expect(response).to include_json(
         deal_group: {
diff --git a/spec/lib/active_campaign/api/tags_spec.rb b/spec/lib/active_campaign/api/tags_spec.rb
index 6e1182f..7f60262 100644
--- a/spec/lib/active_campaign/api/tags_spec.rb
+++ b/spec/lib/active_campaign/api/tags_spec.rb
@@ -64,8 +64,7 @@
     end
 
     it 'makes the tag irretrievable' do
-      show_response = client.show_tag(tag_id)
-      expect(show_response).not_to include_json(tag: expected_tag_response)
+      expect { client.show_tag(tag_id) }.to raise_error(ActiveCampaign::ResourceNotFound)
     end
   end
 end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 5842cfe..741cbfc 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -8,6 +8,7 @@
 
 require 'active_campaign'
 
+require_relative 'support/cleanup'
 require_relative 'support/shared_contexts'
 require_relative 'support/webmock'
 require_relative 'support/vcr'
diff --git a/spec/support/cleanup.rb b/spec/support/cleanup.rb
new file mode 100644
index 0000000..faa8c33
--- /dev/null
+++ b/spec/support/cleanup.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+# The client raises ResourceNotFound on 404, and cleanup hooks often delete a
+# resource the example itself already deleted.
+module Cleanup
+  def cleanup
+    yield
+  rescue ActiveCampaign::ResourceNotFound
+    nil
+  end
+end
+
+RSpec.configure do |config|
+  config.include Cleanup
+end
diff --git a/spec/support/shared_contexts.rb b/spec/support/shared_contexts.rb
index 0771376..5f4788c 100644
--- a/spec/support/shared_contexts.rb
+++ b/spec/support/shared_contexts.rb
@@ -31,7 +31,7 @@
   end
 
   after do
-    client.delete_account(account_id) if account_id
+    cleanup { client.delete_account(account_id) } if account_id
   end
 end
 
@@ -80,6 +80,6 @@
   end
 
   after do
-    client.delete_account_contact(account_contact_id) if account_contact_id
+    cleanup { client.delete_account_contact(account_contact_id) } if account_contact_id
   end
 end
diff --git a/spec/support/shared_contexts/with_contact_tag.rb b/spec/support/shared_contexts/with_contact_tag.rb
index 650f771..c17bfa6 100644
--- a/spec/support/shared_contexts/with_contact_tag.rb
+++ b/spec/support/shared_contexts/with_contact_tag.rb
@@ -28,6 +28,6 @@
   let(:contact_tag_id) { contact_tag[:id] }
 
   after do
-    client.delete_contact_tag(contact_tag_id) if contact_tag_id
+    cleanup { client.delete_contact_tag(contact_tag_id) } if contact_tag_id
   end
 end
diff --git a/spec/support/shared_contexts/with_field.rb b/spec/support/shared_contexts/with_field.rb
index 50700d2..8f1e8d8 100644
--- a/spec/support/shared_contexts/with_field.rb
+++ b/spec/support/shared_contexts/with_field.rb
@@ -39,7 +39,7 @@
   let(:field_id) { field[:id] }
 
   after do
-    client.delete_field(field_id) if field_id
+    cleanup { client.delete_field(field_id) } if field_id
   end
 end
 
@@ -162,6 +162,6 @@
   let(:rel_id) { field_rel[:id] }
 
   after do
-    client.delete_field_rel(rel_id) if rel_id
+    cleanup { client.delete_field_rel(rel_id) } if rel_id
   end
 end
diff --git a/spec/support/shared_contexts/with_field_value.rb b/spec/support/shared_contexts/with_field_value.rb
index 647f1b4..7aa23fe 100644
--- a/spec/support/shared_contexts/with_field_value.rb
+++ b/spec/support/shared_contexts/with_field_value.rb
@@ -29,6 +29,6 @@
   let(:field_value_id) { field_value[:id] }
 
   after do
-    client.delete_field_value(field_value_id) if field_value_id
+    cleanup { client.delete_field_value(field_value_id) } if field_value_id
   end
 end
diff --git a/spec/support/shared_contexts/with_tag.rb b/spec/support/shared_contexts/with_tag.rb
index 3a763c1..e170b49 100644
--- a/spec/support/shared_contexts/with_tag.rb
+++ b/spec/support/shared_contexts/with_tag.rb
@@ -27,6 +27,6 @@
   let(:tag_id) { tag[:id] }
 
   after do
-    client.delete_tag(tag_id) if tag_id
+    cleanup { client.delete_tag(tag_id) } if tag_id
   end
 end