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This page explains how to sign and authenticate Coinbase Derivatives Exchange (CDE) REST API endpoints.

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Generating an API Key

API endpoints require authentication to access. To interact with these resources, you must create an API key via the Coinbase Derivatives Command Center (DCC).

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Signing Requests

The CDE REST API requests must include an access signature header.
  • CB-ACCESS-KEY: The API key as a string
  • CB-ACCESS-PASSPHRASE: The Passphrase shown when creating the API key
  • CB-ACCESS-SIGN: The Base64-encoded signature
  • CB-ACCESS-TIMESTAMP: A timestamp for your request

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Selecting a Timestamp

The CB-ACCESS-TIMESTAMP header MUST be number of seconds since Unix Epoch in UTC. Decimal values are not allowed. Make sure to use an integer. Your timestamp should be within 5 seconds of the API service time or your request is considered expired and will be rejected.

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Creating a Signature

The CB-ACCESS-SIGN header is generated by creating an HMAC-SHA-256 using the secret key on the prehash string timestamp + method + requestPath + body (where + represents string concatenation) and Base64-encode the output.
  • timestamp is the same as the CB-ACCESS-TIMESTAMP header.
  • method should be UPPER CASE, e.g., GET or POST.
  • requestPath should only include the path of the API endpoint. Do NOT include the base URL or query parameters when creating the signature. Valid requestPath example to include in the string for hashing: 
    /rest/funding-rate
    Invalid requestPath example: 
    https://api.exchange.fairx.net/rest/funding-rate?symbol=BIPZ30
  • body is the request body string or omitted if there is no request body (typically for GET requests).
Remember to Base64-encode the digest output before sending in the header. That is, the secret should not be Base64 encoded when using HMAC-SHA-256 to sign the request, but the entire resulting message.

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Code Samples

The following examples demonstrate how to sign a message by generating an HMAC signature, setting the headers, and making a GET request to the specified URL. 
import json
import hmac
import hashlib
import time
import base64
import requests
import urllib.parse

method = 'GET'
host_url = 'https://api.exchange.fairx.net"
rest_url = '/rest/funding-rate'
secret_key = 'secret'
timestamp = str(int(time.time()))
passphrase = 'password'
access_key = 'access_key'

params = {
    "symbol": "BIPZ30"
}

request_body = {}
body = json.dumps(request_body) if request_body else ''

message = timestamp + method + urllib.parse.urlparse(rest_url).path + body
hmac_key = base64.b64decode(secret_key)
signature = hmac.new(hmac_key, message.encode('utf-8'), digestmod=hashlib.sha256).digest()
signature_b64 = base64.b64encode(signature).decode()

headers = {
    "CB-ACCESS-TIMESTAMP": timestamp,
    "CB-ACCESS-SIGN": signature_b64,
    "CB-ACCESS-PASSPHRASE": passphrase,
    "CB-ACCESS-KEY": access_key
}

response = requests.get(host_url + rest_url, headers=headers, params=params)
print(response.json())