Does a thin client testnet wallet exist which allows offline signing?

Question

I appreciate I can do offline singing with bitcoin-core, but it's complex. To make it easier, I would have to download the entire blockchain.

I have searched up electrum, but can't seem to find a testnet option.

Any ideas?

Answer 1

Testnet transactions have the same format as mainnet transactions, so you can just create a raw transaction on your online testnet wallet, and get it signed by Electrum with a private key it thinks is associated with a mainnet address (the version byte is different, so the same hexadecimal private key will generate a different address on the testnet and on the mainnet, but the signature will still be valid).

Answer 2

It looks like a testnet option was merged in early 2017, but I'm not sure if it was released:

https://github.com/spesmilo/electrum/commit/d042d6e970389f97331e9caae196bf7a3af1e293

https://github.com/spesmilo/electrum/issues/541

Answer 3

Electrum can be started with the --testnet option to run on testnet.