diff --git a/freqtrade/rpc/api_server/api_backtest.py b/freqtrade/rpc/api_server/api_backtest.py
index 97b7b7989..a008702a9 100644
--- a/freqtrade/rpc/api_server/api_backtest.py
+++ b/freqtrade/rpc/api_server/api_backtest.py
@@ -32,6 +32,10 @@ async def api_start_backtest(bt_settings: BacktestRequest, background_tasks: Bac
     for setting in settings.keys():
         if settings[setting] is not None:
             btconfig[setting] = settings[setting]
+    try:
+        btconfig['stake_amount'] = float(btconfig['stake_amount'])
+    except ValueError:
+        pass
 
     # Force dry-run for backtesting
     btconfig['dry_run'] = True
@@ -57,8 +61,7 @@ async def api_start_backtest(bt_settings: BacktestRequest, background_tasks: Bac
             ):
                 from freqtrade.optimize.backtesting import Backtesting
                 ApiServer._bt = Backtesting(btconfig)
-                if ApiServer._bt.timeframe_detail:
-                    ApiServer._bt.load_bt_data_detail()
+                ApiServer._bt.load_bt_data_detail()
             else:
                 ApiServer._bt.config = btconfig
                 ApiServer._bt.init_backtest()
diff --git a/freqtrade/rpc/api_server/api_schemas.py b/freqtrade/rpc/api_server/api_schemas.py
index ede5dcf0b..e22cf82b3 100644
--- a/freqtrade/rpc/api_server/api_schemas.py
+++ b/freqtrade/rpc/api_server/api_schemas.py
@@ -149,7 +149,7 @@ class ShowConfig(BaseModel):
     api_version: float
     dry_run: bool
     stake_currency: str
-    stake_amount: Union[float, str]
+    stake_amount: str
     available_capital: Optional[float]
     stake_currency_decimals: int
     max_open_trades: int
@@ -366,7 +366,7 @@ class BacktestRequest(BaseModel):
     timeframe_detail: Optional[str]
     timerange: Optional[str]
     max_open_trades: Optional[int]
-    stake_amount: Optional[Union[float, str]]
+    stake_amount: Optional[str]
     enable_protections: bool
     dry_run_wallet: Optional[float]
 
diff --git a/freqtrade/rpc/rpc.py b/freqtrade/rpc/rpc.py
index 377134542..5912a0ecd 100644
--- a/freqtrade/rpc/rpc.py
+++ b/freqtrade/rpc/rpc.py
@@ -112,7 +112,7 @@ class RPC:
             'dry_run': config['dry_run'],
             'stake_currency': config['stake_currency'],
             'stake_currency_decimals': decimals_per_coin(config['stake_currency']),
-            'stake_amount': config['stake_amount'],
+            'stake_amount': str(config['stake_amount']),
             'available_capital': config.get('available_capital'),
             'max_open_trades': (config['max_open_trades']
                                 if config['max_open_trades'] != float('inf') else -1),