diff --git a/crud.py b/crud.py
index 400b5d1..08d29e7 100644
--- a/crud.py
+++ b/crud.py
@@ -15,11 +15,28 @@ from .models import (
     GetNWC,
     NWCNewBudget
 )
+from .paranoia import assert_valid_wallet_id, assert_valid_pubkey, assert_sane_string, assert_valid_timestamp_seconds, assert_valid_msats, assert_valid_positive_int
 
 db = Database("ext_nwcprovider")
 
 
 async def create_nwc(data: CreateNWCKey) -> NWCKey:
+
+    # hardening #
+    assert_valid_pubkey(data.pubkey)
+    assert_valid_wallet_id(data.wallet)
+    assert_sane_string(data.description)
+    assert_valid_timestamp_seconds(data.expires_at)
+    for permission in data.permissions:
+        assert_sane_string(permission)
+
+    if data.budgets:
+        for budget in data.budgets:
+            assert_valid_msats(budget.budget_msats)
+            assert_valid_positive_int(budget.refresh_window)
+            assert_valid_timestamp_seconds(budget.created_at)
+    # ## #
+
     nwckey_entry = NWCKey(
         pubkey=data.pubkey,
         wallet=data.wallet,
@@ -43,6 +60,12 @@ async def create_nwc(data: CreateNWCKey) -> NWCKey:
 
 
 async def delete_nwc(data: DeleteNWC) -> None:
+
+    # hardening #
+    assert_valid_pubkey(data.pubkey)
+    assert_valid_wallet_id(data.wallet)
+    # ## #
+
     await db.execute(
         "DELETE FROM nwcprovider.keys WHERE pubkey = :pubkey AND wallet = :wallet",
         {"pubkey": data.pubkey, "wallet": data.wallet},
@@ -50,6 +73,13 @@ async def delete_nwc(data: DeleteNWC) -> None:
 
 
 async def get_wallet_nwcs(data: GetWalletNWC) -> List[NWCKey]:
+    expires =  int(time.time()) if not data.include_expired else -1
+    
+    # hardening #
+    assert_valid_wallet_id(data.wallet)
+    assert_valid_timestamp_seconds(expires)
+    # ## #
+
     return await db.fetchall(
         """
         SELECT * FROM nwcprovider.keys
@@ -57,15 +87,23 @@ async def get_wallet_nwcs(data: GetWalletNWC) -> List[NWCKey]:
         """,
         {
             "wallet": data.wallet,
-            "expires": int(time.time()) if not data.include_expired else -1,
+            "expires": expires,
         },
         model=NWCKey,
     )
 
 
 async def get_nwc(data: GetNWC) -> Optional[NWCKey]:
+    expires =  int(time.time()) if not data.include_expired else -1
+
+    # hardening #
+    assert_valid_pubkey(data.pubkey)
+    assert_valid_timestamp_seconds(expires)
+    # ## #
+
     # expires_at = 0 means it never expires
     if data.wallet:
+        assert_valid_wallet_id(data.wallet)
         row = await db.fetchone(
             """
             SELECT * FROM nwcprovider.keys
@@ -75,7 +113,7 @@ async def get_nwc(data: GetNWC) -> Optional[NWCKey]:
             {
                 "pubkey": data.pubkey,
                 "wallet": data.wallet,
-                "expires": int(time.time()) if not data.include_expired else -1,
+                "expires": expires,
             },
             NWCKey,
         )
@@ -87,7 +125,7 @@ async def get_nwc(data: GetNWC) -> Optional[NWCKey]:
             """,
             {
                 "pubkey": data.pubkey,
-                "expires": int(time.time()) if not data.include_expired else -1,
+                "expires": expires,
             },
             NWCKey,
         )
@@ -105,6 +143,11 @@ async def get_nwc(data: GetNWC) -> Optional[NWCKey]:
 
 
 async def get_budgets_nwc(data: GetBudgetsNWC) -> Optional[NWCBudget]:
+    
+    # hardening #
+    assert_valid_pubkey(data.pubkey)
+    # ## #
+
     rows = await db.fetchall(
         "SELECT * FROM nwcprovider.budgets WHERE pubkey = :pubkey",
         {"pubkey": data.pubkey},
@@ -113,6 +156,12 @@ async def get_budgets_nwc(data: GetBudgetsNWC) -> Optional[NWCBudget]:
     if data.calculate_spent:
         for budget in budgets:
             last_cycle, next_cycle = budget.get_timestamp_range()
+            
+            # hardening #
+            assert_valid_timestamp_seconds(last_cycle)
+            assert_valid_timestamp_seconds(next_cycle)
+            # ## #
+
             tot_spent_in_range_msats = await db.fetchone(
                 """
                 SELECT SUM(amount_msats) FROM nwcprovider.spent
@@ -126,12 +175,23 @@ async def get_budgets_nwc(data: GetBudgetsNWC) -> Optional[NWCBudget]:
                 },
             )           
             tot_spent_in_range_msats = next(iter(tot_spent_in_range_msats.values())) or 0
+
+            # hardening #
+            assert_valid_msats(tot_spent_in_range_msats)
+            # ## #
+
             budget.used_budget_msats = tot_spent_in_range_msats
     return budgets
 
 
 async def tracked_spend_nwc(data: TrackedSpendNWC, action):
     async def r():
+
+        # hardening #
+        assert_valid_pubkey(data.pubkey)
+        assert_valid_msats(data.amount_msats)
+        # ## #
+
         created_at = int(time.time())
         budgets = await get_budgets_nwc(GetBudgetsNWC(
             pubkey=data.pubkey
@@ -139,6 +199,12 @@ async def tracked_spend_nwc(data: TrackedSpendNWC, action):
         in_budget = True
         for budget in budgets:
             last_cycle, next_cycle = budget.get_timestamp_range()
+
+            # hardening #
+            assert_valid_timestamp_seconds(last_cycle)
+            assert_valid_timestamp_seconds(next_cycle)
+            # ## #
+
             tot_spent_in_range_msats = (
                 next(iter((await db.fetchone(
                     """
@@ -153,6 +219,12 @@ async def tracked_spend_nwc(data: TrackedSpendNWC, action):
                     },
                 )).values())) or 0
             )
+
+            # hardening #
+            assert_valid_msats(tot_spent_in_range_msats)
+            assert_valid_msats(budget.budget_msats)            
+            # ## #
+
             if tot_spent_in_range_msats + data.amount_msats > budget.budget_msats:
                 in_budget = False
                 break
@@ -185,6 +257,12 @@ async def get_config_nwc(key: str):
 
 
 async def set_config_nwc(key: str, value: str):
+
+    # hardening #
+    assert_sane_string(key)
+    assert_sane_string(value)
+    # ## #
+    
     await db.execute(
         """
         INSERT OR REPLACE INTO nwcprovider.config (key, value)
diff --git a/paranoia.py b/paranoia.py
new file mode 100644
index 0000000..4e56e93
--- /dev/null
+++ b/paranoia.py
@@ -0,0 +1,122 @@
+# Run-time hardening to detect unexpected inputs at the edges
+from loguru import logger
+
+ENABLE_HARDENING = True
+
+def panic(reason:str):
+    if not ENABLE_HARDENING:
+        return
+    logger.error(f"hardening error:  {reason}")
+    raise ValueError(f"hardening error:  {reason}")
+    
+# Throw if string contains any non-printable characters
+def assert_printable(v:str):
+    if not ENABLE_HARDENING:
+        return
+    if not isinstance(v, str):
+        panic("not a string "+str(v))
+    if not v.isprintable():
+        panic("string contains non-printable characters")
+    
+# Check if number is valid int and not NaN
+def assert_valid_int(v:int):
+    if not ENABLE_HARDENING:
+        return
+    if not isinstance(v, int):
+        panic("number is not a valid int")
+    
+# Check if number is valid positive int
+def assert_valid_positive_int(v:int):
+    if not ENABLE_HARDENING:
+        return
+    assert_valid_int(v)
+    if v < 0:
+        panic("number is not positive")
+    
+# Check if number is a valid sats amount
+def assert_valid_sats(v:int):
+    if not ENABLE_HARDENING:
+        return
+    assert_valid_positive_int(v)
+    max_sats_value = 10_000_000 
+    if v >= max_sats_value:
+        panic("sats amount looks too high")
+    
+# Check if number is a valid msats amount
+def assert_valid_msats(v:int):
+    if not ENABLE_HARDENING:
+        return
+    assert_valid_positive_int(v)
+    max_msats_value = 10_000_000 * 1000
+    if v >= max_msats_value:
+        panic("msats amount looks too high")
+    
+
+# Check if string is a valid sha256 hash
+def assert_valid_sha256(v:str):
+    if not ENABLE_HARDENING:
+        return
+    assert_printable(v)
+    if len(v) != 64 or not all(c in "0123456789abcdef" for c in v):
+        panic("string is not a valid sha256 hash")
+    
+# Check if valid nostr pubkey
+def assert_valid_pubkey(v:str):
+    if not ENABLE_HARDENING:
+        return
+    assert_valid_sha256(v)
+    
+
+# Check if valid wallet id
+def assert_valid_wallet_id(v:str):
+    if not ENABLE_HARDENING:
+        return
+    assert_printable(v)
+    if not v.isalnum():
+        panic("string is not a valid wallet id")
+
+
+# Check if valid timestamp in seconds
+def assert_valid_timestamp_seconds(v:int):
+    if not ENABLE_HARDENING:
+        return
+    assert_valid_int(v)
+    if v < 0:
+        panic("timestamp is negative")
+    if v > 2**31:
+        panic("timestamp is too high")
+
+# Check if string is within sane parameters
+def assert_sane_string(v:str):
+    if not ENABLE_HARDENING:
+        return
+    assert_printable(v)
+    if len(v) > 1024:
+        panic("string is too long")
+    
+
+# Check if string is a non-empty string
+def assert_non_empty_string(v:str):
+    if not ENABLE_HARDENING:
+        return
+    assert_printable(v)
+    if len(v.strip()) == 0:
+        panic("string is empty")
+    
+# Assert valid json
+def assert_valid_json(v:str):
+    if not ENABLE_HARDENING:
+        return
+    assert_non_empty_string(v)
+    try:
+        import json
+        json.loads(v)
+    except:
+        panic("string is not valid json")
+
+# Check if string is a valid bolt11 invoice
+def assert_valid_bolt11(invoice:str):
+    if not ENABLE_HARDENING:
+        return
+    assert_printable(invoice)
+    
diff --git a/tasks.py b/tasks.py
index 9ca9bf7..4b89913 100644
--- a/tasks.py
+++ b/tasks.py
@@ -22,6 +22,7 @@ from .execution_queue import execution_queue
 from .models import NWCKey, TrackedSpendNWC, GetNWC
 from .nwcp import NWCServiceProvider
 from .permission import nwc_permissions
+from .paranoia import assert_valid_wallet_id, assert_valid_pubkey, assert_sane_string, assert_valid_timestamp_seconds, assert_valid_msats, assert_valid_positive_int, assert_valid_bolt11, assert_valid_sha256
 
 
 async def _check(nwc: Optional[NWCKey], method: str) -> Optional[Dict]:
@@ -55,6 +56,16 @@ async def _process_invoice(
     amount_msats: int,
     description: Optional[str] = None,
 ):
+    
+    # hardening #
+    assert_valid_wallet_id(wallet_id)
+    assert_valid_pubkey(pubkey)
+    assert_valid_bolt11(invoice)
+    assert_valid_msats(amount_msats)
+    if description:
+        assert_sane_string(description)
+    # ## #
+
     async def execute_payment() -> str :
         payment = await pay_invoice(
             wallet_id=wallet_id,
@@ -114,6 +125,11 @@ async def _on_pay_invoice(
     pubkey: str,
     payload: Dict
 ) -> List[Tuple[Optional[Dict], Optional[Dict], List]]:
+    
+    # hardening #
+    assert_valid_pubkey(pubkey)
+    # ## #
+
     nwc = await get_nwc(GetNWC(
         pubkey=pubkey, 
         refresh_last_used=True
@@ -130,6 +146,12 @@ async def _on_pay_invoice(
         raise Exception("Missing invoice")
     invoice_data = bolt11_decode(invoice)
     amount_msats = int(invoice_data.amount_msat or 0)
+
+    # hardening #
+    assert_valid_bolt11(invoice)
+    assert_valid_msats(amount_msats)
+    # ## #
+
     res = await _process_invoice(
         nwc.wallet, pubkey, invoice, amount_msats, invoice_data.description
     )
@@ -149,6 +171,11 @@ async def _on_multi_pay_invoice(
     pubkey: str,
     payload: Dict
 ) -> List[Tuple[Optional[Dict], Optional[Dict], List]]:
+    
+    # hardening #
+    assert_valid_pubkey(pubkey)
+    # ## #
+
     nwc = await get_nwc(GetNWC(pubkey=pubkey, refresh_last_used=True))
     error = await _check(nwc, "multi_pay_invoice")
     if error:
@@ -171,6 +198,12 @@ async def _on_multi_pay_invoice(
             invoice = i.get("invoice", None)
             invoice_data = bolt11_decode(invoice)
             amount_msats = int(invoice_data.amount_msat or 0)
+
+            # hardening #
+            assert_valid_bolt11(invoice)
+            assert_valid_msats(amount_msats)
+            # ## #
+
             res = await _process_invoice(
                 nwc.wallet, pubkey, invoice, amount_msats, invoice_data.description
             )
@@ -197,6 +230,11 @@ async def _on_make_invoice(
     pubkey: str,
     payload: Dict
 ) -> List[Tuple[Optional[Dict], Optional[Dict], List]]:
+    
+    # hardening #
+    assert_valid_pubkey(pubkey)
+    # ## #
+
     nwc = await get_nwc(GetNWC(pubkey=pubkey, refresh_last_used=True))
     error = await _check(nwc, "make_invoice")
     if error:
@@ -211,6 +249,17 @@ async def _on_make_invoice(
     description = params.get("description", "")
     description_hash = params.get("description_hash", None)
     expiry = params.get("expiry", None)
+
+    # hardening #
+    assert_valid_msats(amount_msats)
+    if description:
+        assert_sane_string(description)
+    if description_hash:
+        assert_valid_sha256(description_hash)
+    if expiry:
+        assert_valid_timestamp_seconds(expiry)
+    # ## #
+    
     payment = await create_invoice(
         wallet_id=nwc.wallet,
         amount=int(amount_msats / 1000),
@@ -253,6 +302,11 @@ async def _on_lookup_invoice(
     pubkey: str,
     payload: Dict
 ) -> List[Tuple[Optional[Dict], Optional[Dict], List]]:
+    
+    # hardening #
+    assert_valid_pubkey(pubkey)
+    # ## #
+
     nwc = await get_nwc(GetNWC(pubkey=pubkey, refresh_last_used=True))
     error = await _check(nwc, "lookup_invoice")
     if error:
@@ -269,6 +323,12 @@ async def _on_lookup_invoice(
     if not payment_hash:
         invoice_data = bolt11_decode(invoice)
         payment_hash = invoice_data.payment_hash
+
+    # hardening #
+    assert_valid_sha256(payment_hash)
+    assert_valid_bolt11(invoice)
+    # ## #
+    
     # Get payment data
     payment = await get_wallet_payment(nwc.wallet, payment_hash)
     if not payment:
@@ -304,6 +364,10 @@ async def _on_list_transactions(
     pubkey: str,
     payload: Dict
 ) -> List[Tuple[Optional[Dict], Optional[Dict], List]]:
+    # hardening #
+    assert_valid_pubkey(pubkey)
+    # ## #
+
     nwc = await get_nwc(GetNWC(pubkey=pubkey, refresh_last_used=True))
     error = await _check(nwc, "list_transactions")
     if error:
@@ -316,6 +380,15 @@ async def _on_list_transactions(
     offset = payload.get("offset", 0)
     unpaid = payload.get("unpaid", False)
     tx_type = payload.get("type", None)
+
+    # hardening #
+    assert_valid_positive_int(tfrom)
+    assert_valid_positive_int(tto)
+    assert_valid_positive_int(limit)
+    assert_valid_positive_int(offset)
+    assert_sane_string(tx_type)
+    # ## #
+
     values = []
     filters: Filters = Filters()
     filters.where(["time <= ?"])
@@ -363,6 +436,11 @@ async def _on_get_balance(
     pubkey: str,
     payload: Dict
 ) -> List[Tuple[Optional[Dict], Optional[Dict], List]]:
+    
+    # hardening #
+    assert_valid_pubkey(pubkey)
+    # ## #
+
     nwc = await get_nwc(GetNWC(pubkey=pubkey, refresh_last_used= True))
     error = await _check(nwc, "get_balance")
     if error:
@@ -383,6 +461,11 @@ async def _on_get_info(
     pubkey: str,
     payload: Dict
 ) -> List[Tuple[Optional[Dict], Optional[Dict], List]]:
+    
+    # hardening #
+    assert_valid_pubkey(pubkey)
+    # ## #
+
     nwc = await get_nwc(GetNWC(pubkey=pubkey, refresh_last_used=True))
     error = await _check(nwc, "get_info")
     if error:
diff --git a/views_api.py b/views_api.py
index 2bd68fb..fcd755e 100644
--- a/views_api.py
+++ b/views_api.py
@@ -28,6 +28,7 @@ from .models import (
     GetBudgetsNWC
 )
 from .permission import nwc_permissions
+from .paranoia import assert_valid_wallet_id, assert_valid_pubkey, assert_sane_string
 
 nwcprovider_api_router = APIRouter()
 
@@ -53,6 +54,11 @@ async def api_get_nwcs(
     wallet: WalletTypeInfo = Depends(require_admin_key),
 ):
     wallet_id = wallet.wallet.id
+
+    # hardening #
+    assert_valid_wallet_id(wallet_id)
+    # ## # 
+
     wallet_nwcs = GetWalletNWC(
         wallet=wallet_id, 
         include_expired=include_expired
@@ -82,6 +88,12 @@ async def api_get_nwc(
     wallet: WalletTypeInfo = Depends(require_admin_key)
 ) -> NWCGetResponse:
     wallet_id = wallet.wallet.id
+
+    # hardening #
+    assert_valid_pubkey(pubkey)
+    assert_valid_wallet_id(wallet_id)
+    # ## #
+
     nwc = await get_nwc(GetNWC(pubkey=pubkey, wallet=wallet_id, include_expired=include_expired))
     if not nwc:
         raise Exception("Pubkey has no associated wallet")
@@ -103,6 +115,11 @@ async def api_get_pairing_url(
     req: Request, 
     secret: str
 ) -> str:
+    
+    # hardening #
+    assert_sane_string(secret)
+    # ## #
+
     pprivkey: Optional[str] = await get_config_nwc("provider_key")
     if not pprivkey:
         raise Exception("Extension is not configured")
@@ -147,6 +164,12 @@ async def api_register_nwc(
     wallet: WalletTypeInfo = Depends(require_admin_key),
 ):
     wallet_id = wallet.wallet.id
+
+    # hardening #
+    assert_valid_pubkey(pubkey)
+    assert_valid_wallet_id(wallet_id)
+    # ## #
+
     nwc = await create_nwc(
         CreateNWCKey(
             pubkey=pubkey,
@@ -176,6 +199,12 @@ async def api_delete_nwc(
     wallet: WalletTypeInfo = Depends(require_admin_key)
 ):
     wallet_id = wallet.wallet.id
+
+    # hardening #
+    assert_valid_pubkey(pubkey)
+    assert_valid_wallet_id(wallet_id)
+    # ## #
+
     await delete_nwc(DeleteNWC(
         pubkey=pubkey, 
         wallet=wallet_id
@@ -217,6 +246,13 @@ async def api_get_config_nwc(key: str):
 )
 async def api_set_config_nwc(req: Request):
     data = await req.json()
+
+    # hardening #
+    for key, value in data.items():
+        assert_sane_string(key)
+        assert_sane_string(value)
+    # ## #
+
     for key, value in data.items():
         await set_config_nwc(key, value)
     return await api_get_all_config_nwc()