diff --git a/app/controllers/api/v4/legacy_data_dumps_controller.rb b/app/controllers/api/v4/legacy_data_dumps_controller.rb
new file mode 100644
index 0000000000..a2ef68c4e0
--- /dev/null
+++ b/app/controllers/api/v4/legacy_data_dumps_controller.rb
@@ -0,0 +1,56 @@
+class Api::V4::LegacyDataDumpsController < APIController
+  def create
+    legacy_dump = LegacyMobileDataDump.new(legacy_dump_params)
+
+    if legacy_dump.save
+      log_success(legacy_dump)
+
+      render json: {id: legacy_dump.id, status: "ok"}, status: :ok
+    else
+      log_failure(legacy_dump)
+
+      render json: {errors: legacy_dump.errors.full_messages}, status: :unprocessable_entity
+    end
+  end
+
+  private
+
+  def legacy_dump_params
+    {
+      raw_payload: raw_payload,
+      dump_date: Time.current.utc,
+      user: current_user,
+      mobile_version: mobile_version
+    }
+  end
+
+  def raw_payload
+    {
+      "patients" => params.require(:patients)
+    }
+  end
+
+  def mobile_version
+    request.headers["HTTP_X_APP_VERSION"]
+  end
+
+  def log_success(legacy_dump)
+    Rails.logger.info(
+      msg: "legacy_data_dump_created",
+      legacy_dump_id: legacy_dump.id,
+      user_id: legacy_dump.user_id,
+      facility_id: current_facility.id,
+      mobile_version: legacy_dump.mobile_version,
+      payload_keys: legacy_dump.raw_payload.keys
+    )
+  end
+
+  def log_failure(legacy_dump)
+    Rails.logger.warn(
+      msg: "legacy_data_dump_failed",
+      user_id: legacy_dump.user_id,
+      facility_id: current_facility&.id,
+      errors: legacy_dump.errors.full_messages
+    )
+  end
+end
diff --git a/app/models/legacy_mobile_data_dump.rb b/app/models/legacy_mobile_data_dump.rb
new file mode 100644
index 0000000000..c6b247d97e
--- /dev/null
+++ b/app/models/legacy_mobile_data_dump.rb
@@ -0,0 +1,7 @@
+class LegacyMobileDataDump < ActiveRecord::Base
+  belongs_to :user
+
+  validates :user, presence: true
+  validates :raw_payload, presence: true
+  validates :dump_date, presence: true
+end
diff --git a/config/routes.rb b/config/routes.rb
index 86a5e0e938..d48555010f 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -128,6 +128,8 @@
     namespace :v4, path: "v4" do
       put "import", to: "imports#import"
 
+      resources :legacy_data_dumps, only: [:create]
+
       scope :blood_sugars do
         get "sync", to: "blood_sugars#sync_to_user"
         post "sync", to: "blood_sugars#sync_from_user"
diff --git a/db/migrate/20260105123000_create_legacy_mobile_data_dumps.rb b/db/migrate/20260105123000_create_legacy_mobile_data_dumps.rb
new file mode 100644
index 0000000000..67b613f143
--- /dev/null
+++ b/db/migrate/20260105123000_create_legacy_mobile_data_dumps.rb
@@ -0,0 +1,14 @@
+class CreateLegacyMobileDataDumps < ActiveRecord::Migration[6.1]
+  def change
+    create_table :legacy_mobile_data_dumps, id: :uuid do |t|
+      t.jsonb :raw_payload, null: false
+      t.datetime :dump_date, null: false
+      t.references :user, type: :uuid, foreign_key: true, null: false
+      t.string :mobile_version
+
+      t.timestamps
+    end
+
+    add_index :legacy_mobile_data_dumps, :dump_date
+  end
+end
diff --git a/db/structure.sql b/db/structure.sql
index 0ff07a878e..2025d0451e 100644
--- a/db/structure.sql
+++ b/db/structure.sql
@@ -613,6 +613,21 @@ CREATE TABLE public.facilities (
 );
 
 
+--
+-- Name: legacy_mobile_data_dumps; Type: TABLE; Schema: public; Owner: -
+--
+
+CREATE TABLE public.legacy_mobile_data_dumps (
+    id uuid DEFAULT public.gen_random_uuid() NOT NULL,
+    raw_payload jsonb NOT NULL,
+    dump_date timestamp without time zone NOT NULL,
+    user_id uuid NOT NULL,
+    mobile_version character varying,
+    created_at timestamp without time zone NOT NULL,
+    updated_at timestamp without time zone NOT NULL
+);
+
+
 --
 -- Name: medical_histories; Type: TABLE; Schema: public; Owner: -
 --
@@ -6297,6 +6312,14 @@ ALTER TABLE ONLY public.facilities
     ADD CONSTRAINT facilities_pkey PRIMARY KEY (id);
 
 
+--
+-- Name: legacy_mobile_data_dumps legacy_mobile_data_dumps_pkey; Type: CONSTRAINT; Schema: public; Owner: -
+--
+
+ALTER TABLE ONLY public.legacy_mobile_data_dumps
+    ADD CONSTRAINT legacy_mobile_data_dumps_pkey PRIMARY KEY (id);
+
+
 --
 -- Name: facility_business_identifiers facility_business_identifiers_pkey; Type: CONSTRAINT; Schema: public; Owner: -
 --
@@ -7143,6 +7166,20 @@ CREATE UNIQUE INDEX index_facilities_on_slug ON public.facilities USING btree (s
 CREATE INDEX index_facilities_on_updated_at ON public.facilities USING btree (updated_at);
 
 
+--
+-- Name: index_legacy_mobile_data_dumps_on_dump_date; Type: INDEX; Schema: public; Owner: -
+--
+
+CREATE INDEX index_legacy_mobile_data_dumps_on_dump_date ON public.legacy_mobile_data_dumps USING btree (dump_date);
+
+
+--
+-- Name: index_legacy_mobile_data_dumps_on_user_id; Type: INDEX; Schema: public; Owner: -
+--
+
+CREATE INDEX index_legacy_mobile_data_dumps_on_user_id ON public.legacy_mobile_data_dumps USING btree (user_id);
+
+
 --
 -- Name: index_facilities_teleconsult_mos_on_facility_id_and_user_id; Type: INDEX; Schema: public; Owner: -
 --
@@ -8344,6 +8381,14 @@ ALTER TABLE ONLY public.facilities
     ADD CONSTRAINT fk_rails_c44117c78f FOREIGN KEY (facility_group_id) REFERENCES public.facility_groups(id);
 
 
+--
+-- Name: legacy_mobile_data_dumps fk_rails_a1b2c3d4e5; Type: FK CONSTRAINT; Schema: public; Owner: -
+--
+
+ALTER TABLE ONLY public.legacy_mobile_data_dumps
+    ADD CONSTRAINT fk_rails_a1b2c3d4e5 FOREIGN KEY (user_id) REFERENCES public.users(id);
+
+
 --
 -- Name: dr_rai_action_plans fk_rails_c6db95d644; Type: FK CONSTRAINT; Schema: public; Owner: -
 --
@@ -8597,5 +8642,5 @@ INSERT INTO "schema_migrations" (version) VALUES
 ('20250924102156'),
 ('20250925094123'),
 ('20251125090819'),
-('20251211073126');
-
+('20251211073126'),
+('20260105123000');
diff --git a/spec/requests/api/v4/legacy_data_dumps_spec.rb b/spec/requests/api/v4/legacy_data_dumps_spec.rb
new file mode 100644
index 0000000000..f10959e82f
--- /dev/null
+++ b/spec/requests/api/v4/legacy_data_dumps_spec.rb
@@ -0,0 +1,161 @@
+require "rails_helper"
+
+RSpec.describe "Legacy Data Dumps", type: :request do
+  let(:request_user) { FactoryBot.create(:user) }
+  let(:request_facility) { request_user.facility }
+
+  let(:headers) do
+    {
+      "HTTP_X_USER_ID" => request_user.id,
+      "HTTP_X_FACILITY_ID" => request_facility.id,
+      "HTTP_AUTHORIZATION" => "Bearer #{request_user.access_token}",
+      "HTTP_X_APP_VERSION" => "2024.1.0",
+      "CONTENT_TYPE" => "application/json",
+      "ACCEPT" => "application/json"
+    }
+  end
+
+  describe "POST /api/v4/legacy_data_dumps" do
+    let(:valid_payload) do
+      {
+        patients: [
+          {
+            id: SecureRandom.uuid,
+            full_name: "Test Patient",
+            age: 45,
+            gender: "male",
+            status: "active",
+
+            medical_histories: [
+              {
+                id: SecureRandom.uuid,
+                diabetes: "unknown",
+                prior_heart_attack: "yes"
+              }
+            ],
+
+            blood_pressures: [
+              {
+                id: SecureRandom.uuid,
+                systolic: 140,
+                diastolic: 90
+              }
+            ],
+
+            blood_sugars: [
+              {
+                id: SecureRandom.uuid,
+                blood_sugar_type: "random",
+                blood_sugar_value: 180
+              }
+            ],
+
+            prescription_drugs: [
+              {
+                id: SecureRandom.uuid,
+                name: "Amlodipine",
+                dosage: "5mg"
+              }
+            ],
+
+            appointments: [
+              {
+                id: SecureRandom.uuid,
+                scheduled_date: "2024-02-01",
+                status: "scheduled"
+              }
+            ],
+
+            encounters: [
+              {
+                id: SecureRandom.uuid,
+                notes: "Follow-up visit"
+              }
+            ]
+          }
+        ]
+      }
+    end
+
+    it "creates a legacy data dump successfully" do
+      expect {
+        post "/api/v4/legacy_data_dumps",
+          params: valid_payload.to_json,
+          headers: headers
+      }.to change(LegacyMobileDataDump, :count).by(1)
+
+      expect(response).to have_http_status(:ok)
+
+      json = JSON.parse(response.body)
+      expect(json["status"]).to eq("ok")
+      expect(json["id"]).to be_present
+    end
+
+    it "stores the raw payload with nested legacy data per patient" do
+      post "/api/v4/legacy_data_dumps",
+        params: valid_payload.to_json,
+        headers: headers
+
+      dump = LegacyMobileDataDump.last
+      expect(dump.raw_payload["patients"]).to be_present
+
+      patient = dump.raw_payload["patients"].first
+
+      expect(patient["medical_histories"]).to be_present
+      expect(patient["blood_pressures"]).to be_present
+      expect(patient["blood_sugars"]).to be_present
+      expect(patient["prescription_drugs"]).to be_present
+      expect(patient["appointments"]).to be_present
+      expect(patient["encounters"]).to be_present
+    end
+
+    it "records the user who made the dump" do
+      post "/api/v4/legacy_data_dumps",
+        params: valid_payload.to_json,
+        headers: headers
+
+      dump = LegacyMobileDataDump.last
+      expect(dump.user).to eq(request_user)
+    end
+
+    it "records the mobile version from headers" do
+      post "/api/v4/legacy_data_dumps",
+        params: valid_payload.to_json,
+        headers: headers
+
+      dump = LegacyMobileDataDump.last
+      expect(dump.mobile_version).to eq("2024.1.0")
+    end
+
+    it "records the dump date" do
+      freeze_time do
+        post "/api/v4/legacy_data_dumps",
+          params: valid_payload.to_json,
+          headers: headers
+
+        dump = LegacyMobileDataDump.last
+        expect(dump.dump_date).to be_within(1.second).of(Time.current)
+      end
+    end
+
+    it "returns unauthorized with invalid token" do
+      invalid_headers = headers.merge("HTTP_AUTHORIZATION" => "Bearer invalid_token")
+
+      post "/api/v4/legacy_data_dumps",
+        params: valid_payload.to_json,
+        headers: invalid_headers
+
+      expect(response).to have_http_status(:unauthorized)
+    end
+
+    it "returns bad request without facility id" do
+      invalid_headers = headers.except("HTTP_X_FACILITY_ID")
+
+      post "/api/v4/legacy_data_dumps",
+        params: valid_payload.to_json,
+        headers: invalid_headers
+
+      expect(response).to have_http_status(:bad_request)
+    end
+  end
+end