diff --git a/script/migrations/convert-absolute-attachment-urls-to-relative.rb b/script/migrations/convert-absolute-attachment-urls-to-relative.rb
new file mode 100644
index 000000000..009b6c4cb
--- /dev/null
+++ b/script/migrations/convert-absolute-attachment-urls-to-relative.rb
@@ -0,0 +1,132 @@
+#!/usr/bin/env ruby
+
+# Convert absolute attachment URLs in rich text content to relative paths.
+# This fixes URLs that were stored with full hostnames (e.g., https://app.fizzy.do/...)
+# making them portable across beta environments and host changes.
+#
+# MUST BE RUN AFTER `decrypt!` when using ActiveRecord Encryption
+#
+# Run locally:
+#   bin/rails runner script/migrations/convert-absolute-attachment-urls-to-relative.rb --help
+#
+# Run via Kamal:
+#   kamal app exec -d <stage> -p --reuse "bin/rails runner script/migrations/convert-absolute-attachment-urls-to-relative.rb --help"
+#
+# Safe to re-run: won't modify already-relative URLs
+
+class ConvertAbsoluteAttachmentUrlsToRelative
+  # Match absolute URLs pointing to Active Storage routes, keeping the account slug
+  ABSOLUTE_URL_PATTERN = %r{https?://[^/]+(/\d+/rails/active_storage/[^"']+)}
+
+  attr_reader :account, :dry_run
+
+  def initialize(account_id: nil, dry_run: false)
+    @account = Account.find_by(external_account_id: account_id)
+    @dry_run = dry_run
+  end
+
+  def run
+    puts "Converting absolute attachment URLs to relative paths"
+    puts dry_run ? "DRY RUN MODE - no changes will be saved" : "LIVE MODE - changes will be saved"
+    puts account ? "Only account: #{account.external_account_id} - #{account.name}" : "For **ALL ACCOUNTS**"
+
+    puts "\nPress ENTER to continue running or CTRL-C to bail..."
+    gets
+
+    puts "\nRunning..."
+
+    # Suppress SQL logs
+    Rails.event.debug_mode = false
+
+    seconds = Benchmark.realtime do
+      suppressing_turbo_broadcasts do
+        convert_urls
+      end
+    end
+
+    puts "\n\n"
+    puts "Finished in %.2f seconds." % seconds
+  end
+
+  private
+    def suppressing_turbo_broadcasts
+      Board.suppressing_turbo_broadcasts do
+        Card.suppressing_turbo_broadcasts do
+          yield
+        end
+      end
+    end
+
+    def convert_urls
+      scanned = 0
+      fixed = 0
+      urls_converted = 0
+
+      action_texts_scope.find_each do |rich_text|
+        scanned += 1
+
+        body = rich_text.body
+
+        edited = false
+        conversions = 0
+
+        body.send(:attachment_nodes).each do |node|
+          url = node["url"]
+          next unless url
+
+          if url.match?(ABSOLUTE_URL_PATTERN)
+            node["url"] = url.gsub(ABSOLUTE_URL_PATTERN, '\1')
+            edited = true
+            conversions += 1
+          end
+        end
+
+        if edited
+          record = rich_text.record
+          puts " - modifying #{record.class.name} #{record.to_param} (account: #{record.account&.external_account_id}) - #{conversions} URL(s)"
+
+          unless dry_run
+            rich_text.update! body: body.fragment.to_html
+          end
+
+          fixed += 1
+          urls_converted += conversions
+        end
+      end
+
+      puts "\n\nConversion complete!"
+      puts "  Rich texts examined: #{scanned}"
+      puts "  Rich texts modified: #{fixed}"
+      puts "  URLs converted: #{urls_converted}"
+    end
+
+    def action_texts_scope
+      # Only examine rich texts that have embedded attachments
+      scope = ActionText::RichText.joins(:embeds_attachments)
+      scope = scope.where(account: account) if account
+      scope
+    end
+end
+
+require "optparse"
+
+options = { account_id: nil, dry_run: true }
+
+OptionParser.new do |opts|
+  opts.banner = "Usage: bin/rails runner #{__FILE__} [options]"
+
+  opts.on("-a", "--account ACCOUNT_ID", "Restrict to a specific account (external_account_id)") do |id|
+    options[:account_id] = id
+  end
+
+  opts.on("--[no-]dry-run", "Run in dry-run mode (default: --dry-run)") do |v|
+    options[:dry_run] = v
+  end
+
+  opts.on("-h", "--help", "Show this help message") do
+    puts opts
+    exit
+  end
+end.parse!
+
+ConvertAbsoluteAttachmentUrlsToRelative.new(**options).run