fix: Use canonical JSON serialization in HMAC signature #191
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Fixes 'Unauthorized/Invalid api key' error when posting orders.
The issue was that the HMAC signature was computed using Python's
str() representation of the body dictionary (e.g., "{'price': '0.3'}")
with single quotes replaced by double quotes. This creates a non-canonical
JSON representation that doesn't match what the server expects.
Changed to use json.dumps(body, separators=(',', ':')) to ensure
canonical, compact JSON serialization that matches Go/TypeScript clients.
This ensures cross-language HMAC consistency and fixes the 401
authentication errors when calling post_order().
Tested and verified working with signature_type=1 (Email/Magic wallet proxy).
Contributor
|
@rinadelph a fix has been merged and version 0.30.0 has been created: #176 |
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Problem
The Python client was throwing
PolyApiException[status_code=401, error_message={'error': 'Unauthorized/Invalid api key'}]when callingpost_order(), even with valid API credentials.Root Cause
The HMAC signature was computed using Python's
str()representation of the body dictionary, which created non-canonical JSON that didn't match the canonical JSON used by Go/TypeScript servers, causing signature validation to fail.Solution
Changed to use canonical JSON serialization with
json.dumps(body, separators=(',', ':'))to ensure compact, canonical JSON that matches across all languages.Changes
py_clob_client/signing/hmac.pyimport jsonstr(body).replace("'", '"')withjson.dumps(body, separators=(',', ':'))Testing
✅ Successfully tested with signature_type=1 (Email/Magic wallet proxy)
✅ Order posting now works - placed and filled order successfully
✅ Order response:
{'status': 'matched', 'success': True}This is the same fix confirmed working by multiple users in related discussions.
Note
Switch HMAC body serialization to canonical JSON (json.dumps with compact separators) to ensure cross-language signature consistency.
build_hmac_signatureinpy_clob_client/signing/hmac.pyto serializebodywithjson.dumps(..., separators=(",", ":"))for canonical JSON.import jsonand remove reliance on Pythonstr()representation.Written by Cursor Bugbot for commit 4e87b8a. This will update automatically on new commits. Configure here.