diff --git a/examples/fireblocks/README.md b/examples/fireblocks/README.md
index e8d9849..dbee457 100644
--- a/examples/fireblocks/README.md
+++ b/examples/fireblocks/README.md
@@ -4,8 +4,29 @@ The Hashlock developer API is **custody-agnostic**: `POST /v1/swaps/:id/legs/:le
 returns *unsigned* transactions, and you sign them with your own key material. This directory shows how to
 sign them with an institutional custodian (Fireblocks; Copper follows the same shape).
 
-> ⚠️ Reference only — documented pattern, not a live-tested integration. Fill in your vault / account IDs
-> and asset IDs, and validate against a testnet vault before production.
+> ✅ **EVM `CONTRACT_CALL` validated live** on Fireblocks Sandbox (Sepolia / `ETH_TEST5`): the unsigned
+> `approve`/`createSwap` from `/v1` signs, broadcasts, and lands on-chain. TRON and Bitcoin paths remain
+> documented references (Fireblocks Sandbox has Sepolia + BTC signet, but **not TRON Nile**). Fill in your
+> own vault id + asset ids before running.
+
+## Environment (sandbox)
+
+```bash
+FIREBLOCKS_API_KEY=<API key id (UUID)>
+FIREBLOCKS_SECRET_KEY_PATH=<path to your RSA private key .key/.pem>
+FIREBLOCKS_VAULT_ACCOUNT_ID=0            # numeric string (default sandbox vault is "0")
+FIREBLOCKS_BASE_URL=https://sandbox-api.fireblocks.io   # prod: https://api.fireblocks.io
+```
+
+Fund the vault from **outside** Fireblocks: add the `ETH_TEST5` asset to the vault, copy its **receive
+address**, and send testnet ETH (gas) + your ERC-20 to it from a faucet or another wallet. A `CONTRACT_CALL`
+does **not** require the ERC-20 to be a Fireblocks-recognised asset — only the on-chain balance at the vault
+address plus native `ETH_TEST5` for gas.
+
+> **Python SDK gotcha:** `fireblocks-sdk` (Python) uses top-level string constants — `VAULT_ACCOUNT`,
+> `ONE_TIME_ADDRESS`, `CONTRACT_CALL` — and `create_transaction(tx_type=…)` (not `operation=`). The
+> **JavaScript** `fireblocks-sdk` uses the enums `PeerType`, `TransactionOperation`, `TransactionStatus`
+> and `createTransaction({ operation, … })`. Both `sign_evm.py` / `sign_evm.ts` reflect their SDK's shape.
 
 ## Two signing models
 
diff --git a/examples/fireblocks/sign_evm.py b/examples/fireblocks/sign_evm.py
index 8fc958b..fee7989 100644
--- a/examples/fireblocks/sign_evm.py
+++ b/examples/fireblocks/sign_evm.py
@@ -4,29 +4,37 @@
 
     pip install hashlock-sdk fireblocks-sdk
 
-Not live-tested — set your vault account id + asset id and validate on a testnet vault first.
+Validated live on Fireblocks Sandbox (Sepolia / ETH_TEST5) — the CONTRACT_CALL signs, broadcasts, and the
+approve/createSwap lands on-chain. NOTE the Python SDK's shape: peer-type/operation are top-level string
+constants (VAULT_ACCOUNT / ONE_TIME_ADDRESS / CONTRACT_CALL), and create_transaction takes `tx_type=`
+(not `operation=`). The base URL for sandbox is https://sandbox-api.fireblocks.io (prod: api.fireblocks.io);
+the vault account id is a small integer string (e.g. "0").
 """
 import os
 import time
 
-from fireblocks_sdk import FireblocksSDK, TransferPeerPath, DestinationTransferPeerPath, PeerType
+from fireblocks_sdk import CONTRACT_CALL, ONE_TIME_ADDRESS, VAULT_ACCOUNT, DestinationTransferPeerPath, FireblocksSDK, TransferPeerPath
 
 from hashlock import HashlockClient
 
 client = HashlockClient(api_key=os.environ["HASHLOCK_API_KEY"])
-fireblocks = FireblocksSDK(os.environ["FIREBLOCKS_API_SECRET"], os.environ["FIREBLOCKS_API_KEY"])
+fireblocks = FireblocksSDK(
+    private_key=open(os.environ["FIREBLOCKS_SECRET_KEY_PATH"]).read(),
+    api_key=os.environ["FIREBLOCKS_API_KEY"],
+    api_base_url=os.environ.get("FIREBLOCKS_BASE_URL", "https://sandbox-api.fireblocks.io"),
+)
 
-VAULT_ACCOUNT_ID = os.environ["FIREBLOCKS_VAULT_ID"]
+VAULT_ACCOUNT_ID = os.environ["FIREBLOCKS_VAULT_ACCOUNT_ID"]  # numeric string, e.g. "0"
 ASSET_ID = "ETH_TEST5"  # Fireblocks asset id for the target chain (Sepolia here)
 
 
 def sign_via_fireblocks(tx: dict) -> str:
     """Submit one unsigned EVM tx as a Fireblocks contract call; return the on-chain hash."""
     resp = fireblocks.create_transaction(
-        operation="CONTRACT_CALL",
+        tx_type=CONTRACT_CALL,
         asset_id=ASSET_ID,
-        source=TransferPeerPath(PeerType.VAULT_ACCOUNT, VAULT_ACCOUNT_ID),
-        destination=DestinationTransferPeerPath(PeerType.ONE_TIME_ADDRESS, one_time_address={"address": tx["to"]}),
+        source=TransferPeerPath(VAULT_ACCOUNT, VAULT_ACCOUNT_ID),
+        destination=DestinationTransferPeerPath(ONE_TIME_ADDRESS, one_time_address={"address": tx["to"]}),
         amount=str(int(tx.get("value") or "0")),  # wei; "0" for approve / createSwap
         extra_parameters={"contractCallData": tx["data"]},
         note="Hashlock HTLC settlement",
@@ -34,10 +42,14 @@ def sign_via_fireblocks(tx: dict) -> str:
     tx_id = resp["id"]
     while True:
         t = fireblocks.get_transaction_by_id(tx_id)
-        if t.get("txHash"):
+        status = t.get("status")
+        # Return only once the tx is mined (CONFIRMING) or fully confirmed (COMPLETED) — NOT on the mere
+        # presence of a txHash — so the dependent createSwap isn't submitted before this approve lands
+        # (createSwap's transferFrom needs the approve's allowance on-chain).
+        if status in ("CONFIRMING", "COMPLETED") and t.get("txHash"):
             return t["txHash"]
-        if t["status"] in ("FAILED", "BLOCKED", "CANCELLED", "REJECTED"):
-            raise RuntimeError(f"Fireblocks tx {tx_id} {t['status']}: {t.get('subStatus')}")
+        if status in ("FAILED", "BLOCKED", "CANCELLED", "REJECTED"):
+            raise RuntimeError(f"Fireblocks tx {tx_id} {status}: {t.get('subStatus')}")
         time.sleep(3)
 
 
diff --git a/examples/fireblocks/sign_evm.ts b/examples/fireblocks/sign_evm.ts
index a91a10e..7a08c17 100644
--- a/examples/fireblocks/sign_evm.ts
+++ b/examples/fireblocks/sign_evm.ts
@@ -4,7 +4,9 @@
  *
  *   npm i @hashlock-tech/sdk fireblocks-sdk
  *
- * Not live-tested — set your vault account id + asset id and validate on a testnet vault first.
+ * The CONTRACT_CALL flow is validated live on Fireblocks Sandbox (Sepolia); the `PeerType` /
+ * `TransactionOperation` / `TransactionStatus` enums below match the current `fireblocks-sdk`. Set your
+ * own vault account id + asset id. (Python uses different symbols — see sign_evm.py / the README.)
  */
 import { HashlockClient, type EvmBuild } from '@hashlock-tech/sdk';
 import { FireblocksSDK, PeerType, TransactionOperation, TransactionStatus } from 'fireblocks-sdk';
@@ -27,10 +29,12 @@ async function signViaFireblocks(tx: { to: string; data: string; value?: string
     note: 'Hashlock HTLC settlement',
   });
 
-  // Poll to completion. Fireblocks broadcasts; the tx hash appears on SUBMITTED/COMPLETED.
+  // Return only once the tx is mined (CONFIRMING) or fully confirmed (COMPLETED) — NOT on the mere
+  // presence of a txHash — so the dependent createSwap isn't submitted before this approve lands
+  // (createSwap's transferFrom needs the approve's allowance on-chain).
   for (;;) {
     const t = await fireblocks.getTransactionById(id);
-    if (t.txHash) return t.txHash;
+    if ((t.status === TransactionStatus.CONFIRMING || t.status === TransactionStatus.COMPLETED) && t.txHash) return t.txHash;
     if ([TransactionStatus.FAILED, TransactionStatus.BLOCKED, TransactionStatus.CANCELLED, TransactionStatus.REJECTED].includes(t.status)) {
       throw new Error(`Fireblocks tx ${id} ${t.status}: ${t.subStatus}`);
     }