Make token and chain settings configurable via .env

.env.example.base-mainnet

@@ -0,0 +1,24 @@
+# Application Settings
+APP_NAME=Payment Link Service
+APP_LOGO=/static/logo.png
+APP_HOST=0.0.0.0
+APP_PORT=8000
+APP_BASE_URL=http://localhost:8000
+
+# x402 Payment Settings
+NETWORK=base
+FACILITATOR_URL=https://x402f1.secondstate.io
+MAX_TIMEOUT_SECONDS=60
+
+# Token Settings (USDC on Base Mainnet)
+TOKEN_ADDRESS=0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913
+TOKEN_NAME=USD Coin
+TOKEN_SYMBOL=USDC
+TOKEN_DECIMALS=6
+
+# Chain Settings (Base Mainnet)
+CHAIN_ID=8453
+EXPLORER_URL=https://basescan.org/tx/
+
+# Database Settings
+DATABASE_PATH=payments.db

.env.example → .env.example.base-sepolia

@@ -11,5 +11,15 @@ NETWORK=base-sepolia
 FACILITATOR_URL=https://x402f1.secondstate.io
 MAX_TIMEOUT_SECONDS=60
 
+# Token Settings (USDC on Base Sepolia Testnet)
+TOKEN_ADDRESS=0x036CbD53842c5426634e7929541eC2318f3dCF7e
+TOKEN_NAME=USD Coin
+TOKEN_SYMBOL=USDC
+TOKEN_DECIMALS=6
+
+# Chain Settings (Base Sepolia Testnet)
+CHAIN_ID=84532
+EXPLORER_URL=https://sepolia.basescan.org/tx/
+
 # Database Settings
 DATABASE_PATH=payments.db

config.py

@@ -20,12 +20,27 @@ def __init__(self) -> None:
         self.app_base_url: str = os.getenv("APP_BASE_URL", "http://localhost:8000")
 
         # x402 Payment settings
+        # Valid networks: base-sepolia (testnet), base (mainnet)
         self.network: str = os.getenv("NETWORK", "base-sepolia")
         self.facilitator_url: str = os.getenv(
             "FACILITATOR_URL", "https://x402f1.secondstate.io"
         )
         self.max_timeout_seconds: int = int(os.getenv("MAX_TIMEOUT_SECONDS", "60"))
 
+        # Token settings
+        self.token_address: str = os.getenv(
+            "TOKEN_ADDRESS", "0x036CbD53842c5426634e7929541eC2318f3dCF7e"
+        )
+        self.token_name: str = os.getenv("TOKEN_NAME", "USD Coin")
+        self.token_symbol: str = os.getenv("TOKEN_SYMBOL", "USDC")
+        self.token_decimals: int = int(os.getenv("TOKEN_DECIMALS", "6"))
+
+        # Chain settings
+        self.chain_id: int = int(os.getenv("CHAIN_ID", "84532"))
+        self.explorer_url: str = os.getenv(
+            "EXPLORER_URL", "https://sepolia.basescan.org/tx/"
+        )
+
         # Database settings
         self.database_path: str = os.getenv("DATABASE_PATH", "payments.db")
 

main.py

@@ -1,5 +1,6 @@
 """Payment Link Service - A web app for creating x402-protected payment links."""
 
+import traceback
 import uuid
 from contextlib import asynccontextmanager
 from pathlib import Path
@@ -40,8 +41,6 @@ async def lifespan(app: FastAPI) -> AsyncGenerator[None, None]:
 @app.exception_handler(Exception)
 async def global_exception_handler(request: Request, exc: Exception) -> JSONResponse:
     """Catch all unhandled exceptions and return a JSON error response."""
-    import traceback
-
     return JSONResponse(
         status_code=500,
         content={
@@ -71,6 +70,36 @@ async def root() -> Response:
     )
 
 
+@app.get("/create")
+async def create_page() -> Response:
+    """Serve the create payment link page."""
+    create_path = STATIC_DIR / "create-payment-link.html"
+    if create_path.exists():
+        return FileResponse(create_path)
+    return JSONResponse(
+        status_code=404,
+        content={"error": "Page not found"},
+    )
+
+
+@app.get("/config")
+async def get_config() -> dict[str, str | int]:
+    """Return client configuration for the frontend.
+
+    Returns:
+        JSON with network, token, and chain configuration.
+    """
+    return {
+        "network": settings.network,
+        "tokenAddress": settings.token_address,
+        "tokenName": settings.token_name,
+        "tokenSymbol": settings.token_symbol,
+        "tokenDecimals": settings.token_decimals,
+        "chainId": settings.chain_id,
+        "explorerUrl": settings.explorer_url,
+    }
+
+
 @app.get("/create-payment-link")
 async def create_payment_link(
     amount: float = Query(..., gt=0, description="Payment amount in USD"),
@@ -162,11 +191,17 @@ async def pay(payment_id: str, request: Request) -> Response:
         )
 
     # Create payment service for x402 verification
+    headers_dict = dict(request.headers)
+
+    # Normalize header case - x402 library expects 'X-Payment' not 'x-payment'
+    if "x-payment" in headers_dict and "X-Payment" not in headers_dict:
+        headers_dict["X-Payment"] = headers_dict["x-payment"]
+
     try:
         payment_service: PaymentServiceType = PaymentService(
             app_name=settings.app_name,
             app_logo=settings.app_logo,
-            headers=dict(request.headers),
+            headers=headers_dict,
             resource_url=str(request.url),
             price=payment_record["amount"],
             description=f"Payment for order {payment_id}",
@@ -214,6 +249,19 @@ async def pay(payment_id: str, request: Request) -> Response:
         )
 
     # Step 3: Settle payment
+    # Patch httpx timeout - the x402 library doesn't set a timeout for settle(),
+    # but blockchain transactions can take longer than the default 5 seconds
+    import httpx
+
+    original_init = httpx.AsyncClient.__init__
+
+    def patched_init(self: httpx.AsyncClient, *args: object, **kwargs: object) -> None:
+        if "timeout" not in kwargs:
+            kwargs["timeout"] = 60.0  # 60 seconds for blockchain transactions
+        original_init(self, *args, **kwargs)
+
+    httpx.AsyncClient.__init__ = patched_init  # type: ignore[method-assign]
+
     try:
         (
             settle_success,
@@ -226,6 +274,8 @@ async def pay(payment_id: str, request: Request) -> Response:
             status_code=500,
             content={"error": f"Failed to settle payment: {e}"},
         )
+    finally:
+        httpx.AsyncClient.__init__ = original_init  # type: ignore[method-assign]
 
     if not settle_success:
         return create_x402_response(