On 01/04/2017 11:06 PM, Chris Priest via bitcoin-dev wrote: > On 1/3/17, Jonas Schnelli via bitcoin-dev > wrote: >> >> There are plenty, more sane options. If you can't run your own full-node >> as a merchant (trivial), maybe co-use a wallet-service with centralized >> verification (maybe use two of them), I guess Copay would be one of >> those wallets (as an example). Use them in watch-only mode. > > The best way is to connect to the mempool of each miner and check to > see if they have your txid in their mempool. > > https://www.antpool.com/api/is_in_mempool?txid=334847bb... > https://www.f2pool.com/api/is_in_mempool?txid=334847bb... > https://bw.com/api/is_in_mempool?txid=334847bb... > https://bitfury.com/api/is_in_mempool?txid=334847bb... > https://btcc.com/api/is_in_mempool?txid=334847bb... > > If each of these services return "True", and you know those services > so not engage in RBF, then you can assume with great confidence that > your transaction will be in the next block, or in a block very soon. > If any one of those services return "False", then you must assume that > it is possible that there is a double spend floating around, and that > you should wait to see if that tx gets confirmed. The problem is that > not every pool runs such a service to check the contents of their > mempool... > > This is an example of mining centralization increasing the security of > zero confirm. A world connected up to a few web services to determine payment validity is an example of a bitcoin security catastrophe. e