Authentication & Signing

Request Signing

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Request Format

LocationFieldRequiredDescription
HeaderX-API-KEYYesapiKey returned when the API Key is created
QuerytimestampYesUnix millisecond timestamp
QuerysignatureYesHMAC-SHA256 signature, lowercase hex string
BodyJSONDepends on endpointPOST / PUT / DELETE request body

Signature Payload

payload = queryStringWithoutSignature + requestBody
signature = HMAC-SHA256(apiSecret, payload)

Key rules:

  • timestamp must be a Unix millisecond timestamp. The server tolerance window is ±10 seconds.
  • signature is placed in the URL query string, but is not included in the signature payload.
  • The server verifies the original query string after removing signature; it does not reorder query parameters.
  • The query parameter order used for signing must match the actual request URL.
  • If a request body exists, the JSON string used for signing must exactly match the actual transmitted body.
  • Order-related paths perform signature replay checks. Reusing the same signature within a short period returns Signature replay detected.

Server Time

1GET /v1/time

Response example:

1{
2  "code": 0,
3  "message": "success",
4  "data": {
5    "timestamp": 1780473256,
6    "timestampMs": 1780473256708,
7    "iso": "2026-06-03T07:54:16Z",
8    "timezone": "UTC"
9  },
10  "requestId": "req-7cad3113"
11}

Clients should calculate timeOffsetMs = serverTimestampMs - localTimestampMs, then use timestamp = nowMs + timeOffsetMs for subsequent signed requests. If the server returns Timestamp outside of tolerance window, immediately resync time and regenerate the signature.

GET Signing Example

Actual request:

GET /v1/private/order/current?symbol=BTCUSDT&timestamp=1772710377808&signature=...

Signature payload:

symbol=BTCUSDT&timestamp=1772710377808

POST Signing Example

Actual request:

POST /v1/private/order/place?timestamp=1772710377808&signature=...

Request body:

1{"symbol":"BTCUSDT","type":"LIMIT","side":"BUY","price":"85000","quantity":"0.1","timeInForce":"GTC","makerOnly":true,"clientOrderId":"ext-1772710377808-001"}

Signature payload:

timestamp=1772710377808{"symbol":"BTCUSDT","type":"LIMIT","side":"BUY","price":"85000","quantity":"0.1","timeInForce":"GTC","makerOnly":true,"clientOrderId":"ext-1772710377808-001"}

Python Signing Example

1import hashlib
2import hmac
3import json
4import time
5from urllib.parse import urlencode
6
7import requests
8
9BASE_URL = "https://api.6mm.com"
10API_KEY = "YOUR_API_KEY"
11API_SECRET = "YOUR_API_SECRET"
12TIME_OFFSET_MS = 0
13
14def sign(payload: str) -> str:
15    return hmac.new(
16        API_SECRET.encode("utf-8"),
17        payload.encode("utf-8"),
18        hashlib.sha256,
19    ).hexdigest()
20
21def sync_time_offset():
22    global TIME_OFFSET_MS
23    before = int(time.time() * 1000)
24    resp = requests.get(f"{BASE_URL}/v1/time", timeout=5)
25    after = int(time.time() * 1000)
26    resp.raise_for_status()
27
28    server_ts = int(resp.json()["data"]["timestampMs"])
29    local_midpoint = (before + after) // 2
30    TIME_OFFSET_MS = server_ts - local_midpoint
31
32def signed_request(method: str, path: str, params=None, body=None):
33    params = dict(params or {})
34    params["timestamp"] = str(int(time.time() * 1000) + TIME_OFFSET_MS)
35
36    query_string = urlencode(params)
37    body_string = ""
38    if body is not None:
39        body_string = json.dumps(body, separators=(",", ":"), ensure_ascii=False)
40
41    signature = sign(query_string + body_string)
42    url = f"{BASE_URL}{path}?{query_string}&signature={signature}"
43    headers = {
44        "X-API-KEY": API_KEY,
45        "Content-Type": "application/json",
46    }
47    resp = requests.request(method, url, headers=headers, data=body_string if body is not None else None, timeout=10)
48    resp.raise_for_status()
49    return resp.json()
50
51sync_time_offset()
52print(signed_request("GET", "/v1/private/order/current", {"symbol": "BTCUSDT"}))