I used this tool and was able to follow along with the ones I checked: https://github.com/matja/bitcoin-tool https://github.com/matja/bitcoin-tool Most likely

I used this tool and was able to follow along with the ones I checked: https://github.com/matja/bitcoin-tool https://github.com/matja/bitcoin-tool Most likely the discrepancy is that you're using raw base58 instead of base58check $ ./bitcoin-tool --input-type private-key --input-format hex --input 4300d94bef2ee84bd9d0781398fd96daf98e419e403adc41957fb679dfa1facd --output-format base58check --output-type private-key-wif --network bitcoin --public-key-compression compressed KyTxSACvHPPDWnuE9cVi86kDgs59UFyVwx2Y3LPpAs88TqEdCKvb