diff --git a/app/jobs/resolution_proofing_job.rb b/app/jobs/resolution_proofing_job.rb
index d62ff8278e1..213035b9d8b 100644
--- a/app/jobs/resolution_proofing_job.rb
+++ b/app/jobs/resolution_proofing_job.rb
@@ -23,7 +23,7 @@ def perform(
     should_proof_state_id:,
     ipp_enrollment_in_progress:,
     user_id: nil,
-    service_provider_issuer: nil, # rubocop:disable Lint/UnusedMethodArgument
+    service_provider_issuer: nil,
     threatmetrix_session_id: nil,
     request_ip: nil,
     instant_verify_ab_test_discriminator: nil # rubocop:disable Lint/UnusedMethodArgument
@@ -37,9 +37,12 @@ def perform(
       symbolize_names: true,
     )
 
-    applicant_pii = decrypted_args[:applicant_pii]
-
     user = User.find_by(id: user_id)
+    current_sp = ServiceProvider.find_by(issuer: service_provider_issuer)
+
+    applicant_pii = decrypted_args[:applicant_pii]
+    applicant_pii[:uuid_prefix] = current_sp&.app_id
+    applicant_pii[:uuid] = user.uuid
 
     callback_log_data = make_vendor_proofing_requests(
       timer: timer,
@@ -79,7 +82,7 @@ def make_vendor_proofing_requests(
   )
     result = resolution_proofer.proof(
       applicant_pii: applicant_pii,
-      user_email: user&.confirmed_email_addresses&.first&.email,
+      user_email: user.confirmed_email_addresses.first.email,
       threatmetrix_session_id: threatmetrix_session_id,
       request_ip: request_ip,
       should_proof_state_id: should_proof_state_id,
@@ -102,7 +105,7 @@ def make_vendor_proofing_requests(
   def log_threatmetrix_info(threatmetrix_result, user)
     logger_info_hash(
       name: 'ThreatMetrix',
-      user_id: user&.uuid,
+      user_id: user.uuid,
       threatmetrix_request_id: threatmetrix_result.transaction_id,
       threatmetrix_success: threatmetrix_result.success?,
     )
diff --git a/spec/jobs/resolution_proofing_job_spec.rb b/spec/jobs/resolution_proofing_job_spec.rb
index 602b8ea3a90..f6d5bd89db2 100644
--- a/spec/jobs/resolution_proofing_job_spec.rb
+++ b/spec/jobs/resolution_proofing_job_spec.rb
@@ -13,6 +13,7 @@
   let(:should_proof_state_id) { true }
   let(:trace_id) { SecureRandom.uuid }
   let(:user) { create(:user, :fully_registered) }
+  let(:service_provider) { create(:service_provider, app_id: 'fake-app-id') }
   let(:request_ip) { Faker::Internet.ip_v4_address }
   let(:threatmetrix_session_id) { SecureRandom.uuid }
   let(:proofing_device_profiling) { :enabled }
@@ -38,6 +39,7 @@
         encrypted_arguments: encrypted_arguments,
         trace_id: trace_id,
         user_id: user.id,
+        service_provider_issuer: service_provider.issuer,
         threatmetrix_session_id: threatmetrix_session_id,
         request_ip: request_ip,
         ipp_enrollment_in_progress: ipp_enrollment_in_progress,
@@ -498,6 +500,24 @@
       end
     end
 
+    it 'determines the UUID and UUID prefix and passes it to the downstream proofing vendors' do
+      uuid_info = {
+        uuid_prefix: service_provider.app_id,
+        uuid: user.uuid,
+      }
+
+      stub_vendor_requests
+
+      expect_any_instance_of(Proofing::LexisNexis::InstantVerify::Proofer).to receive(:proof).
+        with(hash_including(uuid_info)).and_call_original
+
+      expect_any_instance_of(Proofing::Aamva::Proofer).to receive(:proof).with(
+        hash_including(uuid_info),
+      ).and_call_original
+
+      perform
+    end
+
     def stub_vendor_requests(
       instant_verify_response: LexisNexisFixtures.instant_verify_success_response_json,
       threatmetrix_response: LexisNexisFixtures.ddp_success_response_json,
diff --git a/spec/services/idv/agent_spec.rb b/spec/services/idv/agent_spec.rb
index 523b38445fe..2c042563c51 100644
--- a/spec/services/idv/agent_spec.rb
+++ b/spec/services/idv/agent_spec.rb
@@ -2,7 +2,7 @@
 require 'ostruct'
 
 RSpec.describe Idv::Agent do
-  let(:user) { build(:user) }
+  let(:user) { create(:user) }
 
   let(:bad_phone) do
     Proofing::Mock::AddressMockClient::UNVERIFIABLE_PHONE_NUMBER