Hi ssmith_c, the Bitvavo API is rejecting valid HMAC signatures generated from multiple independent implementations: Python, C++ (OpenSSL), and even raw curl requests all produce identical signatures, yet the API responds with a “signature is invalid” error. I even tried inspecting the traffic with Wireshark, everything looks correct on the client side. So it seems the issue is definitely with Bitvavo’s signature verification rather than our code. Kind regards, Sascha

Hi ssmith_c, Just wanted to update you — the Bitvavo API is rejecting valid HMAC signatures generated from multiple independent implementations: Python, C++ (OpenSSL), and even raw curl requests all produce identical signatures, yet the API responds with a “signature is invalid” error. I even tried inspecting the traffic with Wireshark, everything looks correct on the client side. So it seems the issue is definitely with Bitvavo’s signature verification rather than our code. Best, Sascha