How can I send eth on specific time?

In case the ICO crowd sale starts on 9:00:00 UTC, how can I make txid on 9:00:00 exactly when I send eth?

  • Even if you send ether to other address by your wallet, it needs time to be mined (make a block and include you trasanction). So we don't know when it is exactly mined (it depends gas, status of pool,etc).
    – Kronos
    Commented May 17, 2018 at 3:05

2 Answers 2


You can use a double Oraclize query with a calculated delay.

This works as follows:

 pragma solidity ^0.4.XXX;

    import "github.com/oraclize/ethereum-api/oraclizeAPI.sol";

    contract ExampleContract is usingOraclize {

        uint public time;
        uint public delay;
        uint public desired_time; // 9:00 of desired day/month and year on UNIX time format
        event LogConstructorInitiated(string nextStep);
        event LogTimeUpdated(string time);
        event LogNewOraclizeQuery(string description);

        function ExampleContract() payable {
            LogConstructorInitiated("Constructor was initiated.");
            delay = 0;

        function __callback(bytes32 myid, string result) {
            if (msg.sender != oraclize_cbAddress()) revert();
            time = parseInt(result,0);
            if(time < desiredtime)
              delay= desiredtime - time;
            else if(time == desiredtime || time > desiredtime){
                //do what you want to do at 9:00


        function updateTime() payable {
            if (oraclize_getTime("URL") > this.balance) {
                LogNewOraclizeQuery("Oraclize query was NOT sent, please add some 
                ETH to cover for the query fee");
            } else {
                LogNewOraclizeQuery("Oraclize query was sent, standing by for the answer..");
                oraclize_query(delay, "URL", "xml or json(parsing of the xml or json").parse.parse....;


I did the code fast maybe a quick revision is needed but with this you can get a good idea of what you can/have to do.

Hope it helps!


I believe your best bet at this moment in time is Ethereum Alarm Clock

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