diff --git a/lib/pact_broker/api/decorators/publish_contract_decorator.rb b/lib/pact_broker/api/decorators/publish_contract_decorator.rb
index 48e3c40f7..ec336372f 100644
--- a/lib/pact_broker/api/decorators/publish_contract_decorator.rb
+++ b/lib/pact_broker/api/decorators/publish_contract_decorator.rb
@@ -11,8 +11,13 @@ class PublishContractDecorator < BaseDecorator
         property :provider_name
         property :specification
         property :content_type
-        property :decoded_content
+        property :decoded_content, setter: -> (fragment:, represented:, user_options:, **) {
+          represented.decoded_content = fragment
+          # Set the pact version sha when we set the content
+          represented.pact_version_sha = user_options.fetch(:sha_generator).call(fragment)
+        }
         property :on_conflict, default: "overwrite"
+
       end
     end
   end
diff --git a/lib/pact_broker/api/resources/pact.rb b/lib/pact_broker/api/resources/pact.rb
index 226ec827d..a27c9a4d6 100644
--- a/lib/pact_broker/api/resources/pact.rb
+++ b/lib/pact_broker/api/resources/pact.rb
@@ -71,9 +71,9 @@ def from_json
           subscribe(PactBroker::Integrations::EventListener.new) do
             handle_webhook_events do
               if request.patch? && resource_exists?
-                @pact = pact_service.merge_pact(pact_params)
+                @pact = pact_service.merge_pact(pact_params.merge(pact_version_sha: pact_version_sha))
               else
-                @pact = pact_service.create_or_update_pact(pact_params)
+                @pact = pact_service.create_or_update_pact(pact_params.merge(pact_version_sha: pact_version_sha))
               end
             end
           end
@@ -114,7 +114,7 @@ def pact
         end
 
         def disallowed_modification?
-          if request.really_put? && pact_service.disallowed_modification?(pact, pact_params.json_content)
+          if request.really_put? && pact_service.disallowed_modification?(pact, pact_version_sha)
             message_params = { consumer_name: pact_params.consumer_name, consumer_version_number: pact_params.consumer_version_number, provider_name: pact_params.provider_name }
             set_json_error_message(message("errors.validation.pact_content_modification_not_allowed", message_params))
             true
@@ -126,6 +126,10 @@ def disallowed_modification?
         def schema
           api_contract_class(:put_pact_params_contract)
         end
+
+        def pact_version_sha
+          @pact_version_sha ||= pact_service.generate_sha(pact_params.json_content)
+        end
       end
     end
   end
diff --git a/lib/pact_broker/api/resources/publish_contracts.rb b/lib/pact_broker/api/resources/publish_contracts.rb
index 45b921735..c7e598c6e 100644
--- a/lib/pact_broker/api/resources/publish_contracts.rb
+++ b/lib/pact_broker/api/resources/publish_contracts.rb
@@ -53,7 +53,7 @@ def policy_record_context
         private
 
         def parsed_contracts
-          @parsed_contracts ||= decorator_class(:publish_contracts_decorator).new(PactBroker::Contracts::ContractsToPublish.new).from_hash(params)
+          @parsed_contracts ||= decorator_class(:publish_contracts_decorator).new(PactBroker::Contracts::ContractsToPublish.new).from_hash(params, { user_options: { sha_generator: PactBroker.configuration.sha_generator } } )
         end
 
         def params
diff --git a/lib/pact_broker/contracts/contract_to_publish.rb b/lib/pact_broker/contracts/contract_to_publish.rb
index 96a7ad5a5..a710925cf 100644
--- a/lib/pact_broker/contracts/contract_to_publish.rb
+++ b/lib/pact_broker/contracts/contract_to_publish.rb
@@ -1,11 +1,10 @@
 module PactBroker
   module Contracts
-    ContractToPublish = Struct.new(:consumer_name, :provider_name, :decoded_content, :content_type, :specification, :on_conflict) do
-      # rubocop: disable Metrics/ParameterLists
-      def self.from_hash(consumer_name: nil, provider_name: nil, decoded_content: nil, content_type: nil, specification: nil, on_conflict: nil)
-        new(consumer_name, provider_name, decoded_content, content_type, specification, on_conflict)
+    ContractToPublish = Struct.new(:consumer_name, :provider_name, :decoded_content, :content_type, :specification, :on_conflict, :pact_version_sha, keyword_init: true) do
+
+      def self.from_hash(hash)
+        new(**hash)
       end
-      # rubocop: enable Metrics/ParameterLists
 
       def pact?
         specification == "pact"
diff --git a/lib/pact_broker/contracts/service.rb b/lib/pact_broker/contracts/service.rb
index 6847419aa..7776bcecb 100644
--- a/lib/pact_broker/contracts/service.rb
+++ b/lib/pact_broker/contracts/service.rb
@@ -57,7 +57,7 @@ def add_pact_conflict_notices(notices, parsed_contracts)
         parsed_contracts.contracts.collect do | contract_to_publish |
           pact_params = create_pact_params(parsed_contracts, contract_to_publish)
           existing_pact = pact_service.find_pact(pact_params)
-          if existing_pact && pact_service.disallowed_modification?(existing_pact, contract_to_publish.decoded_content)
+          if existing_pact && pact_service.disallowed_modification?(existing_pact, contract_to_publish.pact_version_sha)
             add_pact_conflict_notice(notices, parsed_contracts, contract_to_publish, existing_pact.json_content, contract_to_publish.decoded_content)
           end
         end
@@ -134,7 +134,7 @@ def create_pacts(parsed_contracts, base_url)
           pact_params = create_pact_params(parsed_contracts, contract_to_publish)
           existing_pact = pact_service.find_pact(pact_params)
           listener = TriggeredWebhooksCreatedListener.new
-          created_pact = create_or_merge_pact(contract_to_publish.merge?, existing_pact, pact_params, listener)
+          created_pact = create_or_merge_pact(contract_to_publish.merge?, existing_pact, pact_params.merge(pact_version_sha: contract_to_publish.pact_version_sha), listener)
           notices.concat(notices_for_pact(parsed_contracts, contract_to_publish, existing_pact, created_pact, listener, base_url))
           created_pact
         end
diff --git a/lib/pact_broker/pacts/pact_params.rb b/lib/pact_broker/pacts/pact_params.rb
index e7f75723c..c6d9cb733 100644
--- a/lib/pact_broker/pacts/pact_params.rb
+++ b/lib/pact_broker/pacts/pact_params.rb
@@ -20,7 +20,7 @@ def self.from_path_info path_info
         )
       end
 
-      def self.from_request request, path_info
+      def self.from_request(request, path_info)
         json_content = request.body.to_s
         parsed_content = begin
           parsed = JSON.parse(json_content, PACT_PARSING_OPTIONS)
diff --git a/lib/pact_broker/pacts/service.rb b/lib/pact_broker/pacts/service.rb
index fb59bd7ad..6ec1adacb 100644
--- a/lib/pact_broker/pacts/service.rb
+++ b/lib/pact_broker/pacts/service.rb
@@ -22,6 +22,10 @@ module Service
       extend PactBroker::Messages
       extend SquashPactsForVerification
 
+      def generate_sha(json_content)
+        PactBroker.configuration.sha_generator.call(json_content)
+      end
+
       def find_latest_pact params
         pact_repository.find_latest_pact(params[:consumer_name], params[:provider_name], params[:tag], params[:branch_name])
       end
@@ -154,10 +158,12 @@ def find_for_verification_publication(pact_params, consumer_version_selector_has
       end
 
       # Overwriting an existing pact with the same consumer/provider/consumer version number
+      # by creating a new revision (that is, a new PactPublication with an incremented revision number)
+      # Modifing pacts is strongly discouraged now, and support for it will be dropped in the next major version of the Pact Broker
       def create_pact_revision params, existing_pact
         logger.info("Updating existing pact publication", params.without(:json_content))
         logger.debug("Content #{params[:json_content]}")
-        pact_version_sha = generate_sha(params[:json_content])
+        pact_version_sha = params.fetch(:pact_version_sha)
         json_content = add_interaction_ids(params[:json_content])
         update_params = { pact_version_sha: pact_version_sha, json_content: json_content }
         updated_pact = pact_repository.update(existing_pact.id, update_params)
@@ -178,21 +184,20 @@ def create_pact_revision params, existing_pact
 
       private :create_pact_revision
 
-      def disallowed_modification?(existing_pact, new_json_content)
-        !PactBroker.configuration.allow_dangerous_contract_modification && existing_pact && existing_pact.pact_version_sha != generate_sha(new_json_content)
+      def disallowed_modification?(existing_pact, new_pact_version_sha)
+        !PactBroker.configuration.allow_dangerous_contract_modification && existing_pact && existing_pact.pact_version_sha != new_pact_version_sha
       end
 
       # When no publication for the given consumer/provider/consumer version number exists
-      def create_pact params, version, provider
+      def create_pact(params, version, provider)
         logger.info("Creating new pact publication", params.without(:json_content))
         logger.debug("Content #{params[:json_content]}")
-        pact_version_sha = generate_sha(params[:json_content])
         json_content = add_interaction_ids(params[:json_content])
         pact = pact_repository.create(
           version_id: version.id,
           provider_id: provider.id,
           consumer_id: version.pacticipant_id,
-          pact_version_sha: pact_version_sha,
+          pact_version_sha: params.fetch(:pact_version_sha),
           json_content: json_content,
           version: version
         )
@@ -212,12 +217,6 @@ def create_pact params, version, provider
 
       private :create_pact
 
-      def generate_sha(json_content)
-        PactBroker.configuration.sha_generator.call(json_content)
-      end
-
-      private :generate_sha
-
       def add_interaction_ids(json_content)
         Content.from_json(json_content).with_ids.to_json
       end
diff --git a/lib/pact_broker/test/test_data_builder.rb b/lib/pact_broker/test/test_data_builder.rb
index 2cdd4d2b2..92d6bbcbc 100644
--- a/lib/pact_broker/test/test_data_builder.rb
+++ b/lib/pact_broker/test/test_data_builder.rb
@@ -256,7 +256,13 @@ def create_label label_name
       def publish_pact(consumer_name:, provider_name:, consumer_version_number: , tags: nil, branch: nil, build_url: nil, json_content: nil)
         json_content = json_content || random_json_content(consumer_name, provider_name)
         contracts = [
-          PactBroker::Contracts::ContractToPublish.from_hash(consumer_name: consumer_name, provider_name: provider_name, decoded_content: json_content, content_type: "application/json", specification: "pact")
+          PactBroker::Contracts::ContractToPublish.from_hash(
+            consumer_name: consumer_name,
+            provider_name: provider_name,
+            decoded_content: json_content,
+            content_type: "application/json",
+            specification: "pact",
+            pact_version_sha: PactBroker::Pacts::GenerateSha.call(json_content))
         ]
         contracts_to_publish = PactBroker::Contracts::ContractsToPublish.from_hash(
           pacticipant_name: consumer_name,
diff --git a/spec/lib/pact_broker/contracts/service_spec.rb b/spec/lib/pact_broker/contracts/service_spec.rb
index fafa7891f..349fa38f7 100644
--- a/spec/lib/pact_broker/contracts/service_spec.rb
+++ b/spec/lib/pact_broker/contracts/service_spec.rb
@@ -18,10 +18,11 @@ module Contracts
         let(:branch) { "main" }
         let(:contracts) { [contract_1] }
         let(:contract_1) do
-          ContractToPublish.from_hash(
+          ContractToPublish.new(
             consumer_name: "Foo",
             provider_name: "Bar",
             decoded_content: decoded_contract,
+            pact_version_sha: PactBroker::Pacts::GenerateSha.call(decoded_contract),
             specification: "pact",
             on_conflict: on_conflict
           )
@@ -149,17 +150,19 @@ module Contracts
         let(:branch) { "main" }
         let(:contracts) { [contract_1] }
         let(:contract_1) do
-          ContractToPublish.from_hash(
+          ContractToPublish.new(
             consumer_name: "Foo",
             provider_name: "Bar",
             decoded_content: decoded_contract,
             specification: "pact",
-            on_conflict: on_conflict
+            on_conflict: on_conflict,
+            pact_version_sha: new_pact_version_sha
           )
         end
 
         let(:contract_hash) { { consumer: { name: "Foo" }, provider: { name: "Bar" }, interactions: [{a: "b"}] } }
         let(:decoded_contract) { contract_hash.to_json }
+        let(:new_pact_version_sha) { PactBroker::Pacts::GenerateSha.call(decoded_contract) }
 
         subject { Service.conflict_notices(contracts_to_publish, base_url: "base_url") }
 
diff --git a/spec/lib/pact_broker/pacts/service_spec.rb b/spec/lib/pact_broker/pacts/service_spec.rb
index a656a710c..3aa0a156c 100644
--- a/spec/lib/pact_broker/pacts/service_spec.rb
+++ b/spec/lib/pact_broker/pacts/service_spec.rb
@@ -31,7 +31,8 @@ module Pacts
             consumer_name: "Foo",
             provider_name: "Bar",
             consumer_version_number: "1",
-            json_content: json_content
+            json_content: json_content,
+            pact_version_sha: PactBroker::Pacts::GenerateSha.call(json_content)
           }
         end
         let(:content) { double("content") }
@@ -48,12 +49,6 @@ module Pacts
         subject { Service.create_or_update_pact(params) }
 
         context "when no pact exists with the same params" do
-          it "creates the sha before adding the interaction ids" do
-            expect(PactBroker::Pacts::GenerateSha).to receive(:call).ordered
-            expect(content).to receive(:with_ids).ordered
-            subject
-          end
-
           it "saves the pact interactions/messages with ids added to them" do
             expect(pact_repository).to receive(:create).with hash_including(json_content: json_content_with_ids)
             subject
@@ -135,12 +130,6 @@ module Pacts
 
           let(:expected_event_context) { { consumer_version_tags: ["dev"] } }
 
-          it "creates the sha before adding the interaction ids" do
-            expect(PactBroker::Pacts::GenerateSha).to receive(:call).ordered
-            expect(content).to receive(:with_ids).ordered
-            subject
-          end
-
           it "saves the pact interactions/messages with ids added to them" do
             expect(pact_repository).to receive(:update).with(anything, hash_including(json_content: json_content_with_ids))
             subject