The configuration presented is NOT intended to be used on the public network. These are the parameters used for the Catapult Testnet version (MIJIN_TEST).

The central element of every cryptocurrency is a public ledger called the blockchain that links blocks together. Each NEM block can contain up to 200000 transactions.

Since the blocks in the chain and the transactions in the blocks ordered, the complete transaction history is held in the blockchain. Subsequent blocks in the blockchain have increasing heights that differ by one.

Blocks are stored in a database as permanent medium. NEM calls the first block in the chain the nemesis block.

Blocks are generated by accounts. If an account generates a block and the block gets included in the blockchain, the generating account, called the harvester, gets all the transaction fees for transactions that are included in the block. A harvester will therefore usually include as many transactions as possible.

NEM blocks complete every 15 seconds, making transactions confirm quickly enough for everyday use.


A block has the following properties:


The number of seconds elapsed since the creation of the nemesis block.

Previous block hash

The sha3-256 hash of the last blockchain as an hexadecimal string.


The signature of the block. The signature was generated by the signer and can be used to validate that the block data was not modified by a node.


The nemesis block has type -1. The rest of the blocks have type 1.


The array of transaction included in the block.


The block version. It can represent:

  • Main network
  • Test network
  • Mijin network
  • Mijin Test network (Catapult)


The public key of the harvester of the block as a hexadecimal number.


The height of the blockchain. Each blockchain has a unique height. Subsequent blocks differ in height by 1.