7 Bybit API Python Errors and How to Fix Them

If you're building a Bybit trading bot in Python, you will hit errors. The Bybit V5 API is well-documented, but the error messages are often terse retCode integers that require digging through docs to decode. This guide covers the 7 most common Bybit API Python errors — the exact error output, the root cause, and a working fix you can paste in. All code uses the pybit library ( pip install pybit ). If you're evaluating different bot architectures, see how AutoTrading compares to freqtrade and Jesse . Error 1: retCode: 10003 — Invalid API Key Error output: { "retCode" : 10003 , "retMsg" : "API key is invalid." , "result" : {}} Root cause: You're using a testnet API key against the mainnet endpoint (or vice versa). Fix: Bybit testnet and mainnet require separate API keys. The pybit HTTP session takes a testnet boolean — make sure it matches the key you generated. from pybit.unified_trading import HTTP # Testnet session — must use testnet keys session = HTTP ( testnet = True , api_key = "