Currency Conversion Fails

I’m trying to convert cryptos but I keep getting this message in the response:
{code=400, message=“Cannot convert BTC to ETH”}

It appears that ONLY USD and USDC pairs are supported. For users with EUR wallet this leaves only USDC. Converting cryptos is one of the main features of coinbase webapp and any exchange. Please support all pairs just like in the webapp.

1 Like


This is my exact issue as well. Got halfway through writing this when I saw this post, so tacking on here.

I am attempting to use the Coinbase Pro Exchange API to convert between ETH and BTC within the Coinbase Pro account that I have. I am unable to successfully complete this conversion and am only receiving an error message stating:

    "message": "Cannot convert ETH to BTC"

What I have tried

I have created an API key for the profile containing my ETH and BTC balances and grated it all three of View/Transfer/Trade permissions. I am able to successfully execute a GET request against the API and return info about my account. This aligns accurately with what is online and on the app. No issues there. Now, when I attempt a POST request as outlined in the documentation here I am unable to actually perform a successful conversion because of the above error. Nowhere online can I find that you are not allowed to convert between ETH and BTC, yet the API is preventing me from doing so.

Minimum Reproducible Example

I am using Python 3.9.2 with the following requirements installed:


and this being the minimum code example to reproduce the issue I am experiencing:

import base64
import hashlib
import hmac
import os
import time

import requests
from requests.auth import AuthBase

class CoinbaseAuth(AuthBase):
    def __init__(self, api_key, secret_key, passphrase):
        self.api_key = api_key or os.getenv("API_KEY")
        self.secret_key = secret_key or os.getenv("SECRET_KEY")
        self.passphrase = passphrase or os.getenv("PASSPHRASE") 

    def __call__(self, request):
        timestamp = str(int(time.time()))

        message = (
            + request.method
            + request.path_url
            + (request.body.decode("utf8") if request.body else "")
        sk = base64.b64decode(self.secret_key)
        hmac_signature =
        signature = base64.b64encode(hmac_signature.digest()).decode("utf8")

        headers = {
            "Accept": "application/json",
            "Content-Type": "application/json",
            "CB-ACCESS-KEY": self.api_key,
            "CB-ACCESS-SIGN": signature,
            "CB-ACCESS-TIMESTAMP": timestamp,
            "CB-ACCESS-PASSPHRASE": self.passphrase,
        return request

auth = CoinbaseAuth(

profile_response = requests.get("", auth=auth)

profiles = response.json()

# I only have 1 profile, but one could iterate through to find the default
profile_id = profiles[0]['id']

conversion_response =
        "profile_id": profile_id,
        "amount": "0.0002",
        "from": "ETH",
        "to": "BTC",

print(f"Status Code: {conversion_response.status_code}")
print(f'Response Body: {conversion_response.content.decode("utf8")}')

and the above code snippet should output the following (because it does for me):

Status Code: 400
Response Body: {"message":"Cannot convert ETH to BTC"}

I just saw this persons issue and it is my exact issue. We should be able to convert between any 2 currencies and not need to use USDC as an intermediary. The Coinbase app allows you to do this so why wouldn’t the “Pro” app also support this same feature?

As an update I have aslo tried converting to USD and USDC and both of those conversions fail as well for the same reason/error. What is the point of a conversions API endpoint that cannot convert anything?

We would like this feature too. Unless I missed it, no one else has asked for this to be resolved which seems very odd.

I only have EUR wallet but just went back and tested USDC and it also fails. So this conversion end point apparently converts nothing for EUR wallet holders. @staff1 nbase @staff1

on sandbox only USD to USDC and USDC to USD works.