This is not what I meant.
Checking transaction, is a way of submitting the transaction hash (base 64 or something like that) before broadcasting it.
Then, the tool can say that the hash is valid or not, It can retrieve the transaction information (amount sent, receiving/submitting addresses, fees...) and also say if it has been signed (using the private key of the sender address)
This is what I meant by checking transaction. this is not looking at blockchain explorer what I meant.
If somebody has one reliable tool to submit and check transactions before broadcast, it would be fine.