diff --git a/db/migrations/20210712_add_interaction_count_to_pact_versions.rb b/db/migrations/20210712_add_interaction_count_to_pact_versions.rb
new file mode 100644
index 000000000..9a0cd5de1
--- /dev/null
+++ b/db/migrations/20210712_add_interaction_count_to_pact_versions.rb
@@ -0,0 +1,8 @@
+Sequel.migration do
+  change do
+    alter_table(:pact_versions) do
+      add_column(:messages_count, Integer)
+      add_column(:interactions_count, Integer)
+    end
+  end
+end
diff --git a/lib/pact_broker/pacts/content.rb b/lib/pact_broker/pacts/content.rb
index b526a7202..c7aecc503 100644
--- a/lib/pact_broker/pacts/content.rb
+++ b/lib/pact_broker/pacts/content.rb
@@ -95,11 +95,11 @@ def content_that_affects_verification_results
       end
 
       def messages
-        pact_hash.is_a?(Hash) ? pact_hash["messages"] : nil
+        pact_hash.is_a?(Hash) && pact_hash["messages"].is_a?(Array) ? pact_hash["messages"] : nil
       end
 
       def interactions
-        pact_hash.is_a?(Hash) ? pact_hash["interactions"] : nil
+        pact_hash.is_a?(Hash) && pact_hash["interactions"].is_a?(Array) ? pact_hash["interactions"] : nil
       end
 
       def messages_or_interactions
diff --git a/lib/pact_broker/pacts/repository.rb b/lib/pact_broker/pacts/repository.rb
index 4d6f43e13..8fdec9b18 100644
--- a/lib/pact_broker/pacts/repository.rb
+++ b/lib/pact_broker/pacts/repository.rb
@@ -20,6 +20,7 @@
 require "pact_broker/pacts/selectors"
 require "pact_broker/feature_toggle"
 require "pact_broker/pacts/pacts_for_verification_repository"
+require "pact_broker/pacts/content"
 
 module PactBroker
   module Pacts
@@ -355,7 +356,9 @@ def create_pact_version consumer_id, provider_id, sha, json_content
           provider_id: provider_id,
           sha: sha,
           content: json_content,
-          created_at: Sequel.datetime_class.now
+          created_at: Sequel.datetime_class.now,
+          interactions_count: Content.from_json(json_content).interactions&.count || 0,
+          messages_count: Content.from_json(json_content).messages&.count || 0
         ).upsert
       end
 
diff --git a/spec/lib/pact_broker/pacts/content_spec.rb b/spec/lib/pact_broker/pacts/content_spec.rb
index 4dfd89092..aa4da7638 100644
--- a/spec/lib/pact_broker/pacts/content_spec.rb
+++ b/spec/lib/pact_broker/pacts/content_spec.rb
@@ -123,7 +123,7 @@ module Pacts
           end
         end
 
-        context "with both messages and interactions, even though this should never happen" do
+        context "with both messages and interactions (v4)" do
           let(:pact_hash) do
             {
               "ignored" => "foo",
diff --git a/spec/lib/pact_broker/pacts/repository_spec.rb b/spec/lib/pact_broker/pacts/repository_spec.rb
index 50e1e303f..c7ad93fad 100644
--- a/spec/lib/pact_broker/pacts/repository_spec.rb
+++ b/spec/lib/pact_broker/pacts/repository_spec.rb
@@ -17,7 +17,7 @@ module Pacts
         let(:provider) { Pacticipants::Repository.new.create name: "Provider" }
         let(:version) { PactBroker::Versions::Repository.new.create number: "1.2.3", pacticipant_id: consumer.id }
         let(:pact_version_sha) { "123" }
-        let(:json_content) { {some: "json"}.to_json }
+        let(:json_content) { { interactions: ["json"] }.to_json }
 
         let(:params) do
           {
@@ -63,6 +63,16 @@ module Pacts
           expect(LatestPactPublicationIdForConsumerVersion.first.created_at).to eq PactBroker::Domain::Version.find(number: subject.consumer_version_number).created_at
         end
 
+        it "sets the interactions count" do
+          subject
+          expect(PactVersion.order(:id).last.interactions_count).to eq 1
+        end
+
+        it "sets the messages count" do
+          subject
+          expect(PactVersion.order(:id).last.messages_count).to eq 0
+        end
+
         context "when a pact already exists with exactly the same content" do
           let(:another_version) { Versions::Repository.new.create number: "2.0.0", pacticipant_id: consumer.id }