diff --git a/app/models/share.rb b/app/models/share.rb
index b45f97e..8c1a233 100644
--- a/app/models/share.rb
+++ b/app/models/share.rb
@@ -3,6 +3,7 @@ class Share < ApplicationRecord
 
   UTM_SOURCES = %w[
     Bing
+    Bluesky
     ConvertKit
     Facebook
     Google
@@ -42,6 +43,10 @@ class Share < ApplicationRecord
   ].sort!
 
   validates :utm_source, :utm_campaign, :utm_medium, :utm_term, presence: true
+  validates :utm_source,   inclusion: { in: UTM_SOURCES,  allow_blank: true }, on: :create
+  validates :utm_medium,   inclusion: { in: UTM_MEDIUMS,  allow_blank: true }, on: :create
+  validates :utm_campaign, inclusion: { in: UTM_CAMPAIGN, allow_blank: true }, on: :create
+  validates :utm_content,  inclusion: { in: UTM_CONTENT,  allow_blank: true }, on: :create
 
   def calculated_url
     uri = URI(link.url)
diff --git a/spec/factories/shares.rb b/spec/factories/shares.rb
index eecc4c7..81fd484 100644
--- a/spec/factories/shares.rb
+++ b/spec/factories/shares.rb
@@ -1,10 +1,10 @@
 FactoryBot.define do
   factory :share do
     utm_source { 'LinkedIn' }
-    utm_medium { 'community' }
-    utm_campaign { 'campaignOne' }
+    utm_medium { 'Organic' }
+    utm_campaign { 'Blogpromo' }
     utm_term { 'termOne' }
-    utm_content { 'campaignContent' }
+    utm_content { 'Photo' }
     link
   end
 end
diff --git a/spec/models/share_spec.rb b/spec/models/share_spec.rb
index 757ffbc..40639c2 100644
--- a/spec/models/share_spec.rb
+++ b/spec/models/share_spec.rb
@@ -1,14 +1,72 @@
 require "rails_helper"
 
 RSpec.describe Share do
+  before do
+    allow_any_instance_of(Link).to receive(:fetch_social_media_snippets).and_return([])
+  end
+
   describe "#valid?" do
     context "when it does not have a link or the minimum requirements" do
       it "is not valid" do
         link = Share.new
-        
+
         expect(link.valid?).to be_falsey
         expect(link.errors.full_messages).to eq ["Link must exist", "Utm source can't be blank", "Utm campaign can't be blank", "Utm medium can't be blank", "Utm term can't be blank"]
       end
     end
+
+    context "on create with an unrecognized utm_source" do
+      it "is not valid" do
+        share = build(:share, utm_source: "NotARealSource")
+
+        expect(share.valid?(:create)).to be_falsey
+        expect(share.errors[:utm_source]).to include("is not included in the list")
+      end
+    end
+
+    context "on create with Bluesky as utm_source" do
+      it "is valid" do
+        share = build(:share, utm_source: "Bluesky")
+
+        expect(share.valid?(:create)).to be_truthy
+      end
+    end
+
+    context "on create with an unrecognized utm_medium" do
+      it "is not valid" do
+        share = build(:share, utm_medium: "community")
+
+        expect(share.valid?(:create)).to be_falsey
+        expect(share.errors[:utm_medium]).to include("is not included in the list")
+      end
+    end
+
+    context "on create with an unrecognized utm_campaign" do
+      it "is not valid" do
+        share = build(:share, utm_campaign: "campaignOne")
+
+        expect(share.valid?(:create)).to be_falsey
+        expect(share.errors[:utm_campaign]).to include("is not included in the list")
+      end
+    end
+
+    context "on create with an unrecognized utm_content" do
+      it "is not valid" do
+        share = build(:share, utm_content: "Custom")
+
+        expect(share.valid?(:create)).to be_falsey
+        expect(share.errors[:utm_content]).to include("is not included in the list")
+      end
+    end
+
+    context "when updating an existing record whose utm_source is no longer in the list" do
+      it "is allowed (validations are :create-only)" do
+        share = create(:share)
+        share.update_column(:utm_source, "LegacyValue")
+
+        share.shortened_url = "https://example.com/abc"
+        expect(share.save).to be_truthy
+      end
+    end
   end
-end
\ No newline at end of file
+end
diff --git a/spec/requests/api_links_spec.rb b/spec/requests/api_links_spec.rb
index 73c9af0..ae27ea0 100644
--- a/spec/requests/api_links_spec.rb
+++ b/spec/requests/api_links_spec.rb
@@ -73,8 +73,8 @@
       fastruby_link.social_media_snippets.create!(content: 'Tweet 1', social_media_type: 'Twitter')
       fastruby_link.social_media_snippets.create!(content: 'LI 1',    social_media_type: 'LinkedIn')
       fastruby_link.shares.create!(
-        utm_source: 'LinkedIn', utm_medium: 'community',
-        utm_campaign: 'campaignOne', utm_term: 'termOne'
+        utm_source: 'LinkedIn', utm_medium: 'Organic',
+        utm_campaign: 'Blogpromo', utm_term: 'termOne'
       )
     end
 
@@ -104,8 +104,8 @@
   describe 'GET /links/:link_id/shares.json' do
     let!(:share) do
       fastruby_link.shares.create!(
-        utm_source: 'LinkedIn', utm_medium: 'community',
-        utm_campaign: 'campaignOne', utm_term: 'termOne'
+        utm_source: 'LinkedIn', utm_medium: 'Organic',
+        utm_campaign: 'Blogpromo', utm_term: 'termOne'
       )
     end
 
@@ -140,8 +140,8 @@
       {
         share: {
           utm_source: 'LinkedIn',
-          utm_medium: 'community',
-          utm_campaign: 'campaignOne',
+          utm_medium: 'Organic',
+          utm_campaign: 'Blogpromo',
           utm_term: 'termOne',
           utm_content: 'Photo'
         }