How to check if a transaction is still in the blockchain?

Question

Say we want to confirm that a value transaction tx has reached certain finality, which we define as waiting for 12 block confirmations. We do this to drop the probability of tx getting lost due a fork or it getting included in an uncle block.

The examples I've seen use getBlock and/or getTransaction first to make sure tx was mined in a block.

They then wait until 12 new blocks have been mined and seem to use getTransactionReceipt to check if tx is still in the blockchain.

• Is there some functional difference in this context between using getTransaction and getTransactionReceipt to check if tx still has blockNumber? The implementations don't seem to use any of the additional data returned by getTransactionReceipt making it slightly confusing.

• Lets say a fork happened or tx got into an orphaned block before 12 confirmations. Does this mean that getTransaction and getTransactionReceipt will return null for the transaction or how is this reflected in these calls?

Answer 1

No, there is no difference in this case-- they are essentially equivalent. If the tx is orphaned, they should return null, but you should still check the block number because it may have been added to the new chain later than you expect, giving less probability of finality.