Klayr Core


Table of Contents


The Klayr Core blockchain client is an implementation of the Klayr protocol that verifies data (blocks and transactions) against the protocol rules and keeps the network secure.

To provide a high level overview, the main functionalities are listed below:

  • The possibility to connect to a subset of peers in the Klayr mainchain’s P2P network.

  • To synchronize with the Klayr blockchain including requesting, forwarding and processing of the blocks, which also contain the transactions.

  • To maintain the transaction pool, which might contain a subset of unconfirmed transactions.

  • To request and forward the unconfirmed transactions.

  • To possibly generate new blocks when running a validator node.

Furthermore, Klayr Core nodes are able to store all current addresses, balances, and transactions.

With the latest version of Klayr Core, there will be new configurable settings and the modules described in the Modules sub-section will also be used.


After installation, Klayr Core can be connected to the mainchain of the different Klayr blockchain networks.

Follow the associated links to learn more about the Klayr blockchain networks and their mainchains.


The Klayr Core v4 makes full use of the modules defined by Klayr SDK v6. Apart from the aforementioned modules, Klayr Core has an additional module called the Legacy module.

  • The Legacy module maintains all accounts on the Klayr mainchain that received balance transfers to their address in the old 8-byte format, and for which no public key is associated. The Legacy module also implements a command allowing validators without a BLS key to register one.


Table 1. Available APIs for Klayr nodes
API Transport Architecture Port (default) Comment Reference

RPC Endpoints



Depends on the network, see: Networks

To enable, enable RPC websockets in the node config.

RPC endpoints

The Klayr API documentation can be found here.