diff --git a/ar-aging-app/.dockerignore b/ar-aging-app/.dockerignore
new file mode 100644
index 0000000..b11b331
--- /dev/null
+++ b/ar-aging-app/.dockerignore
@@ -0,0 +1,16 @@
+.git
+.env
+.env.local
+**/.venv
+**/venv
+**/__pycache__
+**/*.pyc
+**/node_modules
+frontend/dist
+backend/data
+*.xlsx
+*.xls
+*.csv
+*.db
+*.db-shm
+*.db-wal
diff --git a/ar-aging-app/README.md b/ar-aging-app/README.md
index 61dca10..051cc6a 100644
--- a/ar-aging-app/README.md
+++ b/ar-aging-app/README.md
@@ -22,6 +22,14 @@ docs/
 
 ## Run the app
 ```bash
+# 1. Configure MySQL (hosted RDS) + data paths
+cp example.env .env   # then fill in MYSQL_* credentials
+
+# Option A — Docker (backend + Vite hot reload)
+docker compose up --build
+# → http://localhost:5173  (API on :8000; uploads/exports on the ar_data volume)
+
+# Option B — local processes
 make install          # backend deps + npm install
 make backend          # terminal 1 → FastAPI on :8000
 make frontend         # terminal 2 → dashboard on http://localhost:5173
@@ -29,6 +37,9 @@ make frontend         # terminal 2 → dashboard on http://localhost:5173
 Then open http://localhost:5173 → **New Closing** → pick the month → drag in the three Amazon
 files → **Run processing** → review → **Download Full A/R Aging Excel**.
 
+Uploads and exports are stored under `AR_DATA_DIR` (default `backend/data` locally, `/data` in Docker).
+The app connects to MySQL using `MYSQL_*` variables from `.env`.
+
 ## Run the engine headless (CLI)
 ```bash
 cd backend && pip install -r requirements.txt
diff --git a/ar-aging-app/backend/Dockerfile b/ar-aging-app/backend/Dockerfile
new file mode 100644
index 0000000..9c4ed85
--- /dev/null
+++ b/ar-aging-app/backend/Dockerfile
@@ -0,0 +1,16 @@
+FROM python:3.12-slim
+
+WORKDIR /app
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    gcc \
+    && rm -rf /var/lib/apt/lists/*
+
+COPY requirements.txt .
+RUN pip install --no-cache-dir -r requirements.txt
+
+COPY . .
+
+EXPOSE 8000
+
+CMD ["uvicorn", "app.api.main:app", "--host", "0.0.0.0", "--port", "8000", "--reload"]
diff --git a/ar-aging-app/backend/app/config.py b/ar-aging-app/backend/app/config.py
index 1788265..0c688c4 100644
--- a/ar-aging-app/backend/app/config.py
+++ b/ar-aging-app/backend/app/config.py
@@ -3,12 +3,45 @@ from __future__ import annotations
 
 import os
 from pathlib import Path
+from urllib.parse import quote_plus
+
+from dotenv import load_dotenv
+
+# Load ar-aging-app/.env (or cwd) before reading settings.
+_APP_ROOT = Path(__file__).resolve().parent.parent.parent  # .../ar-aging-app
+load_dotenv(_APP_ROOT / ".env")
+load_dotenv()  # also allow cwd overrides
 
 BASE_DIR = Path(__file__).resolve().parent.parent      # .../backend
 DATA_DIR = Path(os.environ.get("AR_DATA_DIR", str(BASE_DIR / "data")))
 UPLOAD_DIR = DATA_DIR / "uploads"
 EXPORT_DIR = DATA_DIR / "exports"
-DB_PATH = Path(os.environ.get("AR_DB_PATH", str(DATA_DIR / "ar_aging.db")))
+
+# MySQL (required)
+MYSQL_HOST = os.environ.get("MYSQL_HOST", "")
+MYSQL_PORT = int(os.environ.get("MYSQL_PORT", "3306"))
+MYSQL_USER = os.environ.get("MYSQL_USER", "")
+MYSQL_PASSWORD = os.environ.get("MYSQL_PASSWORD", "")
+MYSQL_DATABASE = os.environ.get("MYSQL_DATABASE", "")
+MYSQL_SLOW_QUERY_MS = int(os.environ.get("MYSQL_SLOW_QUERY_MS", "500"))
+MYSQL_POOL_SIZE = int(os.environ.get("MYSQL_POOL_SIZE", "10"))
+MYSQL_POOL_RECYCLE = int(os.environ.get("MYSQL_POOL_RECYCLE", "3600"))
+
+
+def mysql_url() -> str:
+    if not all((MYSQL_HOST, MYSQL_USER, MYSQL_DATABASE)):
+        raise RuntimeError(
+            "MYSQL_HOST, MYSQL_USER, and MYSQL_DATABASE are required. "
+            "Copy example.env to .env and fill in credentials."
+        )
+    user = quote_plus(MYSQL_USER)
+    password = quote_plus(MYSQL_PASSWORD)
+    return (
+        f"mysql+pymysql://{user}:{password}"
+        f"@{MYSQL_HOST}:{MYSQL_PORT}/{MYSQL_DATABASE}"
+        f"?charset=utf8mb4"
+    )
+
 
 # Retention: temp uploads/exports older than this are purged (0 = keep forever).
 RETENTION_DAYS = int(os.environ.get("AR_RETENTION_DAYS", "30"))
diff --git a/ar-aging-app/backend/app/db/database.py b/ar-aging-app/backend/app/db/database.py
index 820f31e..3b98e1a 100644
--- a/ar-aging-app/backend/app/db/database.py
+++ b/ar-aging-app/backend/app/db/database.py
@@ -1,30 +1,79 @@
-"""SQLite database setup (SQLAlchemy). Tuned for bulk transaction inserts."""
+"""MySQL database setup (SQLAlchemy)."""
 from __future__ import annotations
 
-from sqlalchemy import create_engine, event
+import logging
+import time
+from urllib.parse import quote_plus
+
+from sqlalchemy import create_engine, event, text
 from sqlalchemy.orm import declarative_base, sessionmaker
 
-from ..config import DB_PATH, ensure_dirs
+from ..config import (
+    MYSQL_DATABASE,
+    MYSQL_HOST,
+    MYSQL_PASSWORD,
+    MYSQL_POOL_RECYCLE,
+    MYSQL_POOL_SIZE,
+    MYSQL_PORT,
+    MYSQL_SLOW_QUERY_MS,
+    MYSQL_USER,
+    ensure_dirs,
+    mysql_url,
+)
 
 ensure_dirs()
 
+logger = logging.getLogger(__name__)
+
+
+def _ensure_database() -> None:
+    """Create MYSQL_DATABASE if it does not exist yet."""
+    user = quote_plus(MYSQL_USER)
+    password = quote_plus(MYSQL_PASSWORD)
+    server_url = (
+        f"mysql+pymysql://{user}:{password}"
+        f"@{MYSQL_HOST}:{MYSQL_PORT}/?charset=utf8mb4"
+    )
+    server_engine = create_engine(server_url, isolation_level="AUTOCOMMIT")
+    try:
+        with server_engine.connect() as conn:
+            conn.execute(
+                text(
+                    f"CREATE DATABASE IF NOT EXISTS `{MYSQL_DATABASE}` "
+                    "CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci"
+                )
+            )
+    finally:
+        server_engine.dispose()
+
+
+_ensure_database()
+
 ENGINE = create_engine(
-    f"sqlite:///{DB_PATH}",
-    connect_args={"check_same_thread": False},
+    mysql_url(),
+    pool_size=MYSQL_POOL_SIZE,
+    pool_recycle=MYSQL_POOL_RECYCLE,
+    pool_pre_ping=True,
     future=True,
 )
 
+if MYSQL_SLOW_QUERY_MS > 0:
+    @event.listens_for(ENGINE, "before_cursor_execute")
+    def _before_cursor_execute(conn, cursor, statement, parameters, context, executemany):
+        conn.info["query_start_time"] = time.perf_counter()
 
-@event.listens_for(ENGINE, "connect")
-def _sqlite_pragmas(dbapi_conn, _rec):
-    cur = dbapi_conn.cursor()
-    cur.execute("PRAGMA journal_mode=WAL")
-    cur.execute("PRAGMA synchronous=NORMAL")
-    cur.execute("PRAGMA foreign_keys=ON")
-    cur.execute("PRAGMA cache_size=-64000")   # ~64 MB page cache
-    cur.execute("PRAGMA busy_timeout=30000")  # wait (don't error) when another writer holds the lock
-    cur.close()
-
+    @event.listens_for(ENGINE, "after_cursor_execute")
+    def _after_cursor_execute(conn, cursor, statement, parameters, context, executemany):
+        start = conn.info.pop("query_start_time", None)
+        if start is None:
+            return
+        elapsed_ms = (time.perf_counter() - start) * 1000
+        if elapsed_ms >= MYSQL_SLOW_QUERY_MS:
+            logger.warning(
+                "Slow query (%.0f ms): %s",
+                elapsed_ms,
+                statement[:500],
+            )
 
 SessionLocal = sessionmaker(bind=ENGINE, autoflush=False, expire_on_commit=False, future=True)
 Base = declarative_base()
@@ -37,13 +86,13 @@ def init_db() -> None:
 
 
 def _migrate() -> None:
-    """Add columns introduced after a DB was first created (SQLite create_all won't)."""
+    """Add columns introduced after a DB was first created (create_all won't alter)."""
     added = {
         "sessions": [
             ("progress_rows_done", "INTEGER DEFAULT 0"),
             ("progress_rows_total", "INTEGER DEFAULT 0"),
             ("eta_seconds", "INTEGER DEFAULT 0"),
-            ("opening_mode", "VARCHAR DEFAULT 'zero'"),
+            ("opening_mode", "VARCHAR(255) DEFAULT 'zero'"),
             ("opening_source_session_id", "INTEGER"),
         ],
         "reconciliation": [
@@ -54,19 +103,29 @@ def _migrate() -> None:
             ("tolerance", "FLOAT DEFAULT 1.0"),
         ],
         "exports": [
-            ("kind", "VARCHAR DEFAULT 'full'"),
+            ("kind", "VARCHAR(255) DEFAULT 'full'"),
         ],
         "transactions": [
-            ("txn_type_en", "VARCHAR"),
+            ("txn_type_en", "VARCHAR(255)"),
             ("storage_flag", "BOOLEAN DEFAULT 0"),
         ],
     }
     with ENGINE.begin() as conn:
+        db_name = conn.execute(text("SELECT DATABASE()")).scalar()
         for table, cols in added.items():
-            existing = {r[1] for r in conn.exec_driver_sql(f"PRAGMA table_info({table})")}
+            existing = {
+                r[0]
+                for r in conn.execute(
+                    text(
+                        "SELECT COLUMN_NAME FROM INFORMATION_SCHEMA.COLUMNS "
+                        "WHERE TABLE_SCHEMA = :schema AND TABLE_NAME = :table"
+                    ),
+                    {"schema": db_name, "table": table},
+                )
+            }
             for name, decl in cols:
                 if name not in existing:
-                    conn.exec_driver_sql(f"ALTER TABLE {table} ADD COLUMN {name} {decl}")
+                    conn.execute(text(f"ALTER TABLE `{table}` ADD COLUMN `{name}` {decl}"))
 
 
 def get_db():
diff --git a/ar-aging-app/backend/app/db/models.py b/ar-aging-app/backend/app/db/models.py
index bc57e74..2b6675a 100644
--- a/ar-aging-app/backend/app/db/models.py
+++ b/ar-aging-app/backend/app/db/models.py
@@ -18,20 +18,20 @@ def _now() -> dt.datetime:
 class Session(Base):
     __tablename__ = "sessions"
     id = Column(Integer, primary_key=True)
-    name = Column(String, nullable=False)
-    reporting_month = Column(String)                 # "2026-01"
+    name = Column(String(255), nullable=False)
+    reporting_month = Column(String(32))                 # "2026-01"
     month_end_date = Column(Date)
-    reporting_currency = Column(String, default="USD")
+    reporting_currency = Column(String(16), default="USD")
     clearing_lag_days = Column(Integer, default=2)
     rounding_tolerance = Column(Float, default=0.01)
     allowance_for_returns = Column(Float, default=0.0)
     manual_adjustment = Column(Float, default=0.0)
-    manual_adjustment_note = Column(String, default="")
+    manual_adjustment_note = Column(String(512), default="")
     # How the opening AR balance is established: zero (default) | carry_forward | manual
-    opening_mode = Column(String, default="zero")
+    opening_mode = Column(String(32), default="zero")
     opening_source_session_id = Column(Integer)
-    status = Column(String, default="draft")         # draft|processing|processed|error
-    progress_stage = Column(String, default="")
+    status = Column(String(32), default="draft")         # draft|processing|processed|error
+    progress_stage = Column(String(255), default="")
     progress_pct = Column(Float, default=0.0)
     progress_rows_done = Column(Integer, default=0)
     progress_rows_total = Column(Integer, default=0)
@@ -51,18 +51,18 @@ class SessionFile(Base):
     __tablename__ = "session_files"
     id = Column(Integer, primary_key=True)
     session_id = Column(Integer, ForeignKey("sessions.id"), nullable=False)
-    filename = Column(String)
-    stored_path = Column(String)
+    filename = Column(String(512))
+    stored_path = Column(String(1024))
     size_bytes = Column(Integer)
-    sha256 = Column(String)
+    sha256 = Column(String(64))
     worksheets = Column(Text)                        # JSON list
-    data_sheet = Column(String)
+    data_sheet = Column(String(255))
     imported_rows = Column(Integer, default=0)
     min_date = Column(Date)
     max_date = Column(Date)
-    currency = Column(String)
-    marketplace = Column(String)
-    status = Column(String, default="uploaded")      # uploaded|parsed|invalid
+    currency = Column(String(16))
+    marketplace = Column(String(64))
+    status = Column(String(32), default="uploaded")      # uploaded|parsed|invalid
     message = Column(Text, default="")
     session = relationship("Session", back_populates="files")
 
@@ -71,9 +71,9 @@ class Settlement(Base):
     __tablename__ = "settlements"
     id = Column(Integer, primary_key=True)
     session_id = Column(Integer, ForeignKey("sessions.id"), nullable=False)
-    marketplace = Column(String)
-    account_type = Column(String)
-    settlement_id = Column(String)
+    marketplace = Column(String(64))
+    account_type = Column(String(64))
+    settlement_id = Column(String(255))
     order_total = Column(Float, default=0.0)
     transfer_total = Column(Float, default=0.0)
     transfer_amount = Column(Float)                  # boundary/received transfer amount if any
@@ -82,7 +82,7 @@ class Settlement(Base):
     row_count = Column(Integer, default=0)
     first_date = Column(Date)
     last_date = Column(Date)
-    status = Column(String)                          # paid|receivable
+    status = Column(String(32))                          # paid|receivable
     session = relationship("Session", back_populates="settlements")
 
 
@@ -93,20 +93,20 @@ class Transaction(Base):
     __tablename__ = "transactions"
     id = Column(Integer, primary_key=True)
     session_id = Column(Integer, ForeignKey("sessions.id"), nullable=False)
-    source_file = Column(String)
-    source_sheet = Column(String)
+    source_file = Column(String(512))
+    source_sheet = Column(String(255))
     source_row = Column(Integer)
-    marketplace = Column(String)
-    settlement_id = Column(String)
-    order_id = Column(String)
-    sku = Column(String)
-    txn_type = Column(String)                        # original (possibly localized) type
-    txn_type_en = Column(String)                     # canonical English type
-    account_type = Column(String)
+    marketplace = Column(String(64))
+    settlement_id = Column(String(255))
+    order_id = Column(String(255))
+    sku = Column(String(255))
+    txn_type = Column(String(255))                        # original (possibly localized) type
+    txn_type_en = Column(String(255))                     # canonical English type
+    account_type = Column(String(64))
     posted_date = Column(Date)
     total = Column(Float, default=0.0)
-    currency = Column(String, default="USD")
-    settlement_status = Column(String)               # paid|receivable
+    currency = Column(String(16), default="USD")
+    settlement_status = Column(String(32))               # paid|receivable
     receivable_flag = Column(Boolean, default=False)
     storage_flag = Column(Boolean, default=False)    # storage-fee detection drill-down
 
@@ -119,8 +119,8 @@ class MappingRule(Base):
     Lets Finance map new/renamed Amazon headers without code changes."""
     __tablename__ = "mapping_rules"
     id = Column(Integer, primary_key=True)
-    normalized_header = Column(String, unique=True, nullable=False)
-    field = Column(String, nullable=False)
+    normalized_header = Column(String(255), unique=True, nullable=False)
+    field = Column(String(128), nullable=False)
     created_at = Column(DateTime, default=_now)
 Index("ix_txn_settlement", Transaction.session_id, Transaction.settlement_id)
 Index("ix_txn_type", Transaction.session_id, Transaction.txn_type)
@@ -131,10 +131,10 @@ class Exception_(Base):
     __tablename__ = "exceptions"
     id = Column(Integer, primary_key=True)
     session_id = Column(Integer, ForeignKey("sessions.id"), nullable=False)
-    category = Column(String)
-    severity = Column(String)                        # error|warning|info
+    category = Column(String(128))
+    severity = Column(String(32))                        # error|warning|info
     detail = Column(Text)
-    source = Column(String, default="")
+    source = Column(String(512), default="")
     session = relationship("Session", back_populates="exceptions")
 
 
@@ -142,10 +142,10 @@ class FxRate(Base):
     __tablename__ = "fx_rates"
     id = Column(Integer, primary_key=True)
     session_id = Column(Integer, ForeignKey("sessions.id"), nullable=False)
-    marketplace = Column(String)
-    currency = Column(String, default="USD")
+    marketplace = Column(String(64))
+    currency = Column(String(16), default="USD")
     rate = Column(Float, default=1.0)
-    source = Column(String, default="manual")
+    source = Column(String(64), default="manual")
     rate_date = Column(Date)
     session = relationship("Session", back_populates="fx_rates")
 
@@ -154,8 +154,8 @@ class Reserve(Base):
     __tablename__ = "reserves"
     id = Column(Integer, primary_key=True)
     session_id = Column(Integer, ForeignKey("sessions.id"), nullable=False)
-    marketplace = Column(String)
-    account_type = Column(String)
+    marketplace = Column(String(64))
+    account_type = Column(String(64))
     amount = Column(Float, default=0.0)
     session = relationship("Session", back_populates="reserves")
 
@@ -164,14 +164,14 @@ class ReceivableResultRow(Base):
     __tablename__ = "receivable_results"
     id = Column(Integer, primary_key=True)
     session_id = Column(Integer, ForeignKey("sessions.id"), nullable=False)
-    marketplace = Column(String)
-    account_type = Column(String)                    # or "TOTAL"
+    marketplace = Column(String(64))
+    account_type = Column(String(64))                    # or "TOTAL"
     additional_sales = Column(Float, default=0.0)
     reserve = Column(Float, default=0.0)
     receivable_local = Column(Float, default=0.0)
     fx_rate = Column(Float, default=1.0)
     receivable_usd = Column(Float, default=0.0)
-    currency = Column(String, default="USD")
+    currency = Column(String(16), default="USD")
 
 
 class ReconciliationRow(Base):
@@ -186,7 +186,7 @@ class ReconciliationRow(Base):
     manual_adjustments = Column(Float)
     final_receivable_usd = Column(Float)
     identity_difference = Column(Float)
-    status = Column(String)
+    status = Column(String(64))
     notes = Column(Text, default="")
     # AR roll-forward components
     received_payouts = Column(Float, default=0.0)   # Σ transfers received (negative)
@@ -198,10 +198,10 @@ class FxRateDaily(Base):
     __tablename__ = "fx_rates_daily"
     id = Column(Integer, primary_key=True)
     session_id = Column(Integer, ForeignKey("sessions.id"), nullable=False)
-    marketplace = Column(String)
+    marketplace = Column(String(64))
     rate_date = Column(Date)
     rate = Column(Float, default=1.0)
-    source = Column(String, default="manual")
+    source = Column(String(64), default="manual")
 
 
 Index("ix_fx_daily", FxRateDaily.session_id, FxRateDaily.marketplace, FxRateDaily.rate_date)
@@ -217,7 +217,7 @@ class MarketPayout(Base):
     __tablename__ = "market_payouts"
     id = Column(Integer, primary_key=True)
     session_id = Column(Integer, ForeignKey("sessions.id"), nullable=False)
-    marketplace = Column(String)
+    marketplace = Column(String(64))
     received_payouts = Column(Float, default=0.0)    # negative
     all_payouts = Column(Float, default=0.0)         # negative
 
@@ -229,10 +229,10 @@ class OpeningBalance(Base):
     __tablename__ = "opening_balances"
     id = Column(Integer, primary_key=True)
     session_id = Column(Integer, ForeignKey("sessions.id"), nullable=False)
-    marketplace = Column(String)
+    marketplace = Column(String(64))
     amount = Column(Float, default=0.0)
-    reason = Column(String, default="")
-    source = Column(String, default="manual")        # manual | carried_forward
+    reason = Column(String(512), default="")
+    source = Column(String(64), default="manual")        # manual | carried_forward
     updated_at = Column(DateTime, default=_now, onupdate=_now)
 
 
@@ -250,7 +250,7 @@ class FinanceControl(Base):
     disbursements = Column(Float)
     closing_receivable = Column(Float)
     tolerance = Column(Float, default=1.0)
-    verified_by = Column(String, default="")
+    verified_by = Column(String(255), default="")
     verified_at = Column(DateTime)
     comment = Column(Text, default="")
 
@@ -259,7 +259,7 @@ class JournalEntry(Base):
     __tablename__ = "journal_entries"
     id = Column(Integer, primary_key=True)
     session_id = Column(Integer, ForeignKey("sessions.id"), nullable=False, unique=True)
-    entry_no = Column(String, default="")
+    entry_no = Column(String(128), default="")
     data = Column(Text, default="")     # JSON: periods + lines + receivable
 
 
@@ -267,8 +267,8 @@ class ExportRecord(Base):
     __tablename__ = "exports"
     id = Column(Integer, primary_key=True)
     session_id = Column(Integer, ForeignKey("sessions.id"), nullable=False)
-    kind = Column(String, default="full")     # full | summary
-    path = Column(String)
-    sha256 = Column(String)
+    kind = Column(String(32), default="full")     # full | summary
+    path = Column(String(1024))
+    sha256 = Column(String(64))
     size_bytes = Column(Integer)
     generated_at = Column(DateTime, default=_now)
diff --git a/ar-aging-app/backend/app/services/store.py b/ar-aging-app/backend/app/services/store.py
index 4c7ef1f..6a30a09 100644
--- a/ar-aging-app/backend/app/services/store.py
+++ b/ar-aging-app/backend/app/services/store.py
@@ -16,9 +16,10 @@ _TXN_COLS = (
     "settlement_id", "order_id", "sku", "txn_type", "txn_type_en", "account_type",
     "posted_date", "total", "currency", "storage_flag",
 )
+# PyMySQL uses %-style placeholders for raw DBAPI executemany.
 _INSERT_SQL = (
     f"INSERT INTO transactions ({', '.join(_TXN_COLS)}) "
-    f"VALUES ({', '.join('?' * len(_TXN_COLS))})"
+    f"VALUES ({', '.join(['%s'] * len(_TXN_COLS))})"
 )
 
 
@@ -30,12 +31,6 @@ class TransactionSink:
         self.batch = batch
         self._buf: list[tuple] = []
         self._conn = ENGINE.raw_connection()
-        # Bulk-import tuning: durability is not critical here (we can re-run a failed job).
-        cur = self._conn.cursor()
-        cur.execute("PRAGMA synchronous=OFF")
-        cur.execute("PRAGMA temp_store=MEMORY")
-        cur.execute("PRAGMA busy_timeout=30000")
-        cur.close()
         self.count = 0
 
     def add(self, rec: dict[str, Any]) -> None:
@@ -60,7 +55,7 @@ class TransactionSink:
         cur.executemany(_INSERT_SQL, self._buf)
         cur.close()
         # Commit each batch so we don't hold a long write lock that starves the progress
-        # updater (a separate connection). synchronous=OFF keeps these commits cheap.
+        # updater (a separate connection).
         self._conn.commit()
         self._buf.clear()
 
@@ -76,14 +71,14 @@ class TransactionSink:
             recv = 1 if (st.status == "receivable"
                          and acct.lower() in RECEIVABLE_ACCOUNT_TYPES) else 0
             cur.execute(
-                "UPDATE transactions SET settlement_status=?, receivable_flag=? "
-                "WHERE session_id=? AND settlement_id=? AND marketplace=? AND account_type=?",
+                "UPDATE transactions SET settlement_status=%s, receivable_flag=%s "
+                "WHERE session_id=%s AND settlement_id=%s AND marketplace=%s AND account_type=%s",
                 (st.status, recv, self.session_id, sid, mkt, acct),
             )
         # transfer rows: never receivable (canonical type covers localized names)
         cur.execute(
             "UPDATE transactions SET receivable_flag=0 "
-            "WHERE session_id=? AND txn_type_en='Transfer'",
+            "WHERE session_id=%s AND txn_type_en='Transfer'",
             (self.session_id,),
         )
         cur.close()
@@ -103,7 +98,7 @@ def clear_session_results(db: OrmSession, session_id: int) -> None:
     db.commit()
 
 
-# Every table that references sessions.id. Foreign keys are enforced (PRAGMA foreign_keys=ON),
+# Every table that references sessions.id. Foreign keys are enforced,
 # so all children must go before the parent row.
 _CHILD_MODELS = (
     models.Transaction, models.Settlement, models.ReceivableResultRow,
diff --git a/ar-aging-app/backend/requirements.txt b/ar-aging-app/backend/requirements.txt
index baf1713..5a070de 100644
--- a/ar-aging-app/backend/requirements.txt
+++ b/ar-aging-app/backend/requirements.txt
@@ -9,7 +9,9 @@ uvicorn[standard]==0.34.0
 python-multipart==0.0.20
 pydantic==2.10.4
 SQLAlchemy==2.0.36
-aiosqlite==0.20.0
+PyMySQL==1.1.1
+cryptography>=42.0.0
+python-dotenv==1.0.1
 
 # Data helpers (optional / analysis)
 pandas>=2.2
diff --git a/ar-aging-app/docker-compose.yml b/ar-aging-app/docker-compose.yml
new file mode 100644
index 0000000..ac33790
--- /dev/null
+++ b/ar-aging-app/docker-compose.yml
@@ -0,0 +1,29 @@
+services:
+  backend:
+    build: ./backend
+    env_file: .env
+    environment:
+      AR_DATA_DIR: /data
+    ports:
+      - "8000:8000"
+    volumes:
+      - ./backend:/app
+      - ar_data:/data
+    command: uvicorn app.api.main:app --host 0.0.0.0 --port 8000 --reload
+
+  frontend:
+    build: ./frontend
+    ports:
+      - "5173:5173"
+    volumes:
+      - ./frontend:/app
+      - frontend_node_modules:/app/node_modules
+    environment:
+      CHOKIDAR_USEPOLLING: "true"
+      VITE_API_PROXY: http://backend:8000
+    depends_on:
+      - backend
+
+volumes:
+  ar_data:
+  frontend_node_modules:
diff --git a/ar-aging-app/example.env b/ar-aging-app/example.env
new file mode 100644
index 0000000..9527d4a
--- /dev/null
+++ b/ar-aging-app/example.env
@@ -0,0 +1,13 @@
+MYSQL_HOST=your-mysql-host.example.com
+MYSQL_PORT=3306
+MYSQL_USER=your_mysql_user
+MYSQL_PASSWORD=your_mysql_password
+MYSQL_DATABASE=account_finance
+MYSQL_SLOW_QUERY_MS=500
+MYSQL_POOL_SIZE=10
+MYSQL_POOL_RECYCLE=3600
+
+# Uploads/exports. Docker Compose sets AR_DATA_DIR=/data (named volume).
+# Leave unset locally to use backend/data.
+# AR_DATA_DIR=/data
+AR_CORS_ORIGINS=http://localhost:5173,http://127.0.0.1:5173
diff --git a/ar-aging-app/frontend/Dockerfile b/ar-aging-app/frontend/Dockerfile
new file mode 100644
index 0000000..f1b6951
--- /dev/null
+++ b/ar-aging-app/frontend/Dockerfile
@@ -0,0 +1,12 @@
+FROM node:20-alpine
+
+WORKDIR /app
+
+COPY package.json package-lock.json* ./
+RUN npm install
+
+COPY . .
+
+EXPOSE 5173
+
+CMD ["npm", "run", "dev", "--", "--host", "0.0.0.0", "--port", "5173"]
diff --git a/ar-aging-app/frontend/vite.config.ts b/ar-aging-app/frontend/vite.config.ts
index 849792e..99f2ffd 100644
--- a/ar-aging-app/frontend/vite.config.ts
+++ b/ar-aging-app/frontend/vite.config.ts
@@ -4,9 +4,13 @@ import react from "@vitejs/plugin-react";
 export default defineConfig({
   plugins: [react()],
   server: {
+    host: true,
     port: 5173,
     proxy: {
-      "/api": { target: "http://localhost:8000", changeOrigin: true },
+      "/api": {
+        target: process.env.VITE_API_PROXY || "http://localhost:8000",
+        changeOrigin: true,
+      },
     },
   },
 });