Since the Altair upgrade, 512 validators are randomly chosen every 256 epochs (~27 hours) to form a sync committee. Validators in this committee receive much higher rewards and face much higher penalties for being offline. This Python (3.7+) application allows you to check if your validators are part of the current committee or are due to be part of the next one and, optionally, be notified by email as soon as one is.

If your beacon node is not at the default address (http://localhost:5052), you can change the url/port in the config.ini file. If you'd like to use an Infura Teku endpoint (which also allows the app to run on a machine without an operational consensus layer client), enter the endpoint url (https://<your project id>:<your project secret>@eth2-beacon-mainnet.infura.io) for the beacon_node_url and leave beacon_node_port blank.

If you'd like to be notified when your validator(s) are in a sync committee, add an email address and your email password in the config.ini, along with the address to send the alerts to. It's only set up for Gmail, I recommend creating an email account specifically to send these emails because a) the password is saved as plain text and b) you need to lessen the account security in order for the script to be able to authenticate with Gmail. To do this, you need go into that account's Google Account settings, click on the Security tab and scroll down until you see "Less secure app access". This needs to be turned on for the email authentication to work.

The idea is that the application is run via a job/task scheduler (eg crontab) and it'll notify you as soon as your validator index appears in the current or next sync committee. The sync committees change every ~27 hours so there's no point checking every minute but a period of an hour will give you plenty of notice.

By default, with the value of number_of_future_committees set to 1, 3 sync committees are shown (the current one, the next one and the one after). Change the number of sync committees to show after the "next" one with this value. Only the validators in the current and next sync committees are known but it might be useful to see the times at which future committees occur.

Run eth_sync_committee.py to launch the application.

Run with -v/--validators followed by validator index numbers (separated by a space) to specify your validator index(es). You'll be prompted to add it/them to the validators file. Once you've added your validator(s) you can run the application without this argument.

Run with -p/--print-all to print all of the validators in the current and next sync committees.

Run with -n/--notify to send an email notification if you have any validators in the current or next sync committee.

Run with -c/--cron to automatically add a cronjob to launch the script after the next sync committee membership is known, which is at the end of that committee's second epoch. This will not work natively on Windows machines.

 $ ./eth_sync_committee -v 1000 2000 3000 4000 5000 6000 7000 8000 9000

 you've specified validators that aren't in the validators file. would you like to add them? y/n n

 checking validators: 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000 and 9000

                              epoch    start date & time    validators
 -----------------------------------------------------------------------------------------------------------------------
 sync committee 6 (current)   75776   2021/11/03 07:46:47   none of your validators are in the current sync committee :(
 current epoch (108 of 256)   75884   2021/11/03 19:17:59   n/a
 sync committee 7 (next)      76032   2021/11/04 11:05:11   none of your validators are in the next sync committee :(
 sync committee 8             76288   2021/11/05 14:23:35   validators in this sync committee are not yet known
 sync committee 9             76544   2021/11/06 17:41:59   validators in this sync committee are not yet known