diff --git a/README.md b/README.md
index cf6a1ff..5936256 100644
--- a/README.md
+++ b/README.md
@@ -1 +1,30 @@
-# examples
\ No newline at end of file
+# Anboto Trading API examples
+
+Sample clients for the [Anboto Trading API](https://anbotolabs.github.io/anboto-api-docs/#anboto-trading-api).
+
+## Authentication (HMAC system-generated keys)
+
+1. Create keys in the Anboto UI (Settings → API).
+2. Build the string to sign (no separators):  
+   `timestamp + apiKey + recvWindow + queryString + jsonBody`
+   - `queryString`: sorted query parameters, e.g. `exchange=BINANCE&symbol=BTC/USDT`
+   - `jsonBody`: compact JSON for POST bodies (`separators=(',', ':')` in Python)
+3. **Decode the secret** before HMAC (do not use the UTF-8 string as the key):
+   - Legacy keys (contain `+`, `/`, or end with `=`): standard Base64 decode
+   - New keys (URL-safe, no padding): URL-safe Base64 decode
+4. `X-SIGN` = standard Base64(`HMAC-SHA256(decoded_secret, string_to_sign)`)
+
+Headers: `X-API-KEY`, `X-TIMESTAMP`, `X-RECV-WINDOW` (default `5000`), `X-SIGN`.
+
+## Base URLs
+
+| Environment | URL |
+|-------------|-----|
+| Mainnet | `https://api.trade.anboto.xyz` |
+| Pro | `https://api.pro.anboto.xyz` |
+| Testnet | `https://api.testnet.anboto.xyz` |
+
+## Projects
+
+- `anboto-python-example/client.py` — Python reference client
+- `anboto-java-example/` — Java (OkHttp) reference client
diff --git a/anboto-java-example/src/main/java/xyz/anboto/example/Client.java b/anboto-java-example/src/main/java/xyz/anboto/example/Client.java
index 4c3afcd..ca4ff8e 100644
--- a/anboto-java-example/src/main/java/xyz/anboto/example/Client.java
+++ b/anboto-java-example/src/main/java/xyz/anboto/example/Client.java
@@ -16,7 +16,16 @@
 
 public class Client {
     final static String API_KEY = "xxx";
-    final static byte[] API_SECRET = Base64.getDecoder().decode("xxx");
+    final static byte[] API_SECRET = decodeSignKey("xxx");
+
+    /** Match api-gw decodeSignKey: legacy standard Base64 or new URL-safe secrets. */
+    static byte[] decodeSignKey(String keyEncoded) {
+        if (keyEncoded.contains("+") || keyEncoded.contains("/") || keyEncoded.endsWith("=")) {
+            return Base64.getDecoder().decode(keyEncoded);
+        }
+        int pad = (4 - (keyEncoded.length() % 4)) % 4;
+        return Base64.getUrlDecoder().decode(keyEncoded + "=".repeat(pad));
+    }
     final static String TIMESTAMP = Long.toString(ZonedDateTime.now().toInstant().toEpochMilli());
     final static String RECV_WINDOW = "5000";
     final static String X_API_KEY = "X-API-KEY";
diff --git a/anboto-python-example/client.py b/anboto-python-example/client.py
index aeb8554..349b7fd 100644
--- a/anboto-python-example/client.py
+++ b/anboto-python-example/client.py
@@ -83,12 +83,19 @@ def get_current_millis():
     return str(int(current_time_seconds * 1000))
 
 
+def decode_sign_key(key_encoded: str) -> bytes:
+    """Match api-gw decodeSignKey: legacy standard Base64 or new URL-safe secrets."""
+    if "+" in key_encoded or "/" in key_encoded or key_encoded.endswith("="):
+        return base64.b64decode(key_encoded)
+    pad = "=" * (-len(key_encoded) % 4)
+    return base64.urlsafe_b64decode(key_encoded + pad)
+
 
 class AnbotoTradingAPI:
     def __init__(self, base_url, api_key, secret_key):
         self.base_url = base_url
         self.api_key = api_key
-        self.secret_key = base64.b64decode(secret_key)  # Decode api_secret
+        self.secret_key = decode_sign_key(secret_key)
         
     def gen_signature(self, timestamp, querystring, body):
         recv_window = "5000"