I know that I can use eosjs to read/query multi_index table data from the chain. However, my goal is to listen to/on these changes. Specifically, I want to receive a notification whenever something happens on-chain.

Therefore, I need a persistent connection to the chain, whether using web sockets, mqtt (pub-sub) or any other real-time protocol. How to do this? does the eosjs library support this?

Of course, I can write a while(true) loop, where I send RPC requests all the time to check if something has changed, but this is not a good solution, so I'm interested if other people already solved this issue.

Also, some websites like https://eosauthority.com/ show real-time data of what is happening on the eosio network. So, how do they do this?

2 Answers 2


dfuse.eosnation.io provides websocket and graphql push services which should accomplish what you are trying to do. See docs.dfuse.eosnation.io for details.

  • But dfuse.eosnation.io is an external service provider and I need to get an api key to use their services. Why can't I do this alone? or rather how do they do this? that's what I'm interested in
    – basilisk
    Commented Nov 9, 2021 at 15:15

you would use the state history plugin which is a web socket of on chain events.

This is commonly referred to as a SHiP node (state history nodeos instance).


block one developed demux-js as well, but should still work https://github.com/EOSIO/demux-js

You can see other history tools here https://developers.eos.io/welcome/latest/tools/history-tools/history-tools

If you want an example of storing certain information in a PostgreSQL database, you can see the atomic assets api: https://github.com/pinknetworkx/eosio-contract-api

Here is an example script to run a SHiP node exposing the web socket on 8887.


if [ ! -d $DATADIR ]; then
  mkdir -p $DATADIR;

nodeos \
--plugin eosio::producer_plugin \
--plugin eosio::chain_plugin \
--plugin eosio::chain_api_plugin \
--plugin eosio::http_plugin \
--plugin eosio::net_plugin \
--plugin eosio::state_history_plugin \
--data-dir $DATADIR"/data" \
--blocks-dir $DATADIR"/blocks" \
--config-dir $DATADIR"/config" \
--producer-name eosio \
--http-server-address \
--state-history-endpoint \
--access-control-allow-origin='*' \
--contracts-console \
--trace-history \
--chain-state-history \
--http-validate-host=false \
--p2p-peer-address $P2P_ADDRESS \
--verbose-http-errors \
--enable-stale-production \
--eos-vm-oc-enable \
--wasm-runtime eos-vm-jit \
--disable-replay-opts \
--genesis-json $DATADIR"/genesis.json" \
>> $DATADIR"/nodeos.log" 2>&1 & \
echo $! > $DATADIR"/eosd.pid"

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