Is it possible to know when a block is mined? Is there any timestamp or event/subscription?

  • Did you try web3.eth.subscribe('newBlockHeaders') ?
    – Ismael
    Feb 12, 2019 at 16:20
  • Yes, but I think you are notify when the block is added or created in the node, but no mined. I am running a testnet with two nodes(one miner and a peer), and first, I get a notification about block X, and then, one of my transactions is added to this block X. Feb 12, 2019 at 18:16

2 Answers 2


Yes, of course. See the manual

  • Is it possible using javascript? Feb 12, 2019 at 14:13

You can use web3js filter to watch for the latest blocks. You can specify the filtering parameters and wait in a watch callback to be triggered on the event of the specified parameters matched.

The below example can work for the newest blocks.

var filter = web3.eth.filter({toBlock:'latest'});
filter.watch(function (error, result) {
         console.log(result.blockNumber, " has been added in chain"); 

You can take a look here for further explanation Webjs Filter API

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