diff --git a/Gemfile b/Gemfile
index 473d9b60fd..215b3df34c 100644
--- a/Gemfile
+++ b/Gemfile
@@ -18,6 +18,7 @@ gem "rubocop-performance"
 gem "rubocop-rails"
 gem "rubocop-rails-omakase"
 
+gem "minitest", "< 6"
 gem "minitest-bisect"
 
 gemspec
diff --git a/lib/active_resource/base.rb b/lib/active_resource/base.rb
index 3c8a4bee14..42965a890b 100644
--- a/lib/active_resource/base.rb
+++ b/lib/active_resource/base.rb
@@ -1472,6 +1472,12 @@ def dup
     # is Json for the final object as it looked after the \save (which would include attributes like +created_at+
     # that weren't part of the original submit).
     #
+    # With <tt>save</tt> validations run by default. If any of them fail
+    # ActiveResource::ResourceInvalid gets raised, and nothing is POSTed to
+    # the remote system. To skip validations, pass <tt>validate: false</tt>. To
+    # validate withing a custom context, pass the <tt>:context</tt> option.
+    # See ActiveResource::Validations for more information.
+    #
     # There's a series of callbacks associated with <tt>save</tt>. If any
     # of the <tt>before_*</tt> callbacks throw +:abort+ the action is
     # cancelled and <tt>save</tt> raises ActiveResource::ResourceInvalid.
@@ -1484,7 +1490,7 @@ def dup
     #   my_company.new? # => false
     #   my_company.size = 10
     #   my_company.save # sends PUT /companies/1 (update)
-    def save
+    def save(**options)
       run_callbacks :save do
         new? ? create : _update
       end
@@ -1495,16 +1501,17 @@ def save
     # If the resource is new, it is created via +POST+, otherwise the
     # existing resource is updated via +PUT+.
     #
-    # With <tt>save!</tt> validations always run. If any of them fail
+    # With <tt>save!</tt> validations run by default. If any of them fail
     # ActiveResource::ResourceInvalid gets raised, and nothing is POSTed to
-    # the remote system.
+    # the remote system. To skip validations, pass <tt>validate: false</tt>. To
+    # validate withing a custom context, pass the <tt>:context</tt> option.
     # See ActiveResource::Validations for more information.
     #
     # There's a series of callbacks associated with <tt>save!</tt>. If any
     # of the <tt>before_*</tt> callbacks throw +:abort+ the action is
     # cancelled and <tt>save!</tt> raises ActiveResource::ResourceInvalid.
-    def save!
-      save || raise(ResourceInvalid.new(nil, self))
+    def save!(**options)
+      save(**options) || raise(ResourceInvalid.new(nil, self))
     end
 
     ##
diff --git a/lib/active_resource/validations.rb b/lib/active_resource/validations.rb
index 4ad5ea6b50..1c86154a42 100644
--- a/lib/active_resource/validations.rb
+++ b/lib/active_resource/validations.rb
@@ -283,7 +283,7 @@ def save_with_validation(options = {})
       # ones. Otherwise we get an endless loop and can never change the
       # fields so as to make the resource valid.
       @remote_errors = nil
-      if perform_validation && valid? || !perform_validation
+      if perform_validation && valid?(options[:context]) || !perform_validation
         save_without_validation
         true
       else
@@ -314,6 +314,14 @@ def load_remote_errors(remote_errors, save_cache = false) # :nodoc:
     # saved.
     # Remote errors can only be cleared by trying to re-save the resource.
     #
+    # If the argument is +false+ (default is +nil+), the context is set to <tt>:create</tt> if
+    # {new_record?}[rdoc-ref:Base#new_record?] is +true+, and to <tt>:update</tt> if it is not.
+    # If the argument is an array of contexts, <tt>post.valid?([:create, :update])</tt>, the validations are
+    # run within multiple contexts.
+    #
+    # \Validations with no <tt>:on</tt> option will run no matter the context. \Validations with
+    # some <tt>:on</tt> option will only run in the specified context.
+    #
     # ==== Examples
     #   my_person = Person.create(params[:person])
     #   my_person.valid?
@@ -324,6 +332,8 @@ def load_remote_errors(remote_errors, save_cache = false) # :nodoc:
     #   # => false
     #
     def valid?(context = nil)
+      context ||= new_record? ? :create : :update
+
       run_callbacks :validate do
         super
         load_remote_errors(@remote_errors, true) if defined?(@remote_errors) && @remote_errors.present?
diff --git a/test/cases/validations_test.rb b/test/cases/validations_test.rb
index 84e1d5fbe5..8317e00e83 100644
--- a/test/cases/validations_test.rb
+++ b/test/cases/validations_test.rb
@@ -8,6 +8,13 @@
 # This test case simply makes sure that they are all accessible by
 # Active Resource objects.
 class ValidationsTest < ActiveSupport::TestCase
+  class DraftProject < ::Project
+    self.element_name = "project"
+
+    validates :name, format: { with: /\ACREATE:/, on: :create }
+    validates :name, format: { with: /\AUPDATE:/, on: :update }
+  end
+
   VALID_PROJECT_HASH = { name: "My Project", description: "A project" }
   def setup
     @my_proj = { "person" => VALID_PROJECT_HASH }.to_json
@@ -32,12 +39,57 @@ def test_fails_save!
     assert_raise(ActiveResource::ResourceInvalid) { p.save! }
   end
 
+  def test_save_with_context
+    p = new_project(summary: nil)
+    assert_not p.save(context: :completed)
+    assert_equal [ "can't be blank" ], p.errors.messages_for(:summary)
+  end
+
+  def test_save_with_default_create_context
+    p = DraftProject.new VALID_PROJECT_HASH.merge(name: "Invalid")
+    assert_not p.save
+    assert_equal [ "is invalid" ], p.errors.messages_for(:name)
+
+    p.name = "CREATE: Valid"
+    assert p.save, "should save"
+    assert_empty p.errors
+  end
+
+  def test_save_with_default_update_context
+    attributes = VALID_PROJECT_HASH.merge(id: 1, name: "CREATE: Created")
+
+    ActiveResource::HttpMock.respond_to do |mock|
+      mock.get "/projects/1.json", {}, attributes.to_json
+      mock.put "/projects/1.json", {}, attributes.to_json
+    end
+
+    p = DraftProject.find(1)
+    assert_not p.save
+    assert_equal [ "is invalid" ], p.errors.messages_for(:name)
+
+    p.name = "UPDATE: Updated"
+    assert p.save, "should save"
+    assert_empty p.errors
+  end
+
+  def test_save_bang_with_context
+    p = new_project(summary: nil)
+    assert_raise(ActiveResource::ResourceInvalid) { p.save!(context: :completed) }
+    assert_equal [ "can't be blank" ], p.errors.messages_for(:summary)
+  end
+
   def test_save_without_validation
     p = new_project(name: nil)
     assert_not p.save
     assert p.save(validate: false)
   end
 
+  def test_save_bang_without_validation
+    p = new_project(name: nil)
+    assert_raises(ActiveResource::ResourceInvalid) { p.save! }
+    assert p.save!(validate: false)
+  end
+
   def test_validate_callback
     # we have a callback ensuring the description is longer than three letters
     p = new_project(description: "a")
@@ -56,6 +108,14 @@ def test_client_side_validation_maximum
     assert_equal [ "is too long (maximum is 10 characters)" ], project.errors[:description]
   end
 
+  def test_validation_context
+    project = new_project(summary: "")
+
+    assert_predicate project, :valid?
+    assert_not project.valid?(:completed)
+    assert_equal [ "can't be blank" ], project.errors.messages_for(:summary)
+  end
+
   def test_invalid_method
     p = new_project
 
diff --git a/test/fixtures/project.rb b/test/fixtures/project.rb
index e9f41f0672..58c5e0a13f 100644
--- a/test/fixtures/project.rb
+++ b/test/fixtures/project.rb
@@ -11,6 +11,7 @@ class Project < ActiveResource::Base
   validates :name, presence: true
   validates :description, presence: false, length: { maximum: 10 }
   validate :description_greater_than_three_letters
+  validates :summary, presence: { on: :completed }
 
   # to test the validate *callback* works
   def description_greater_than_three_letters