Understanding Proof of Importance (PoI) in Blockchain: Simplified Guide for Beginners

Blockchain technology employs various consensus mechanisms, each with different objectives and advantages. 

One is the Proof of Importance (PoI) consensus, which was first implemented in the NEM blockchain network.

The PoI mechanism aims to address common issues that often arise in other consensus methods by offering a more equitable and transparent mining mechanism.

What is Proof of Importance (PoI)?

Proof of Importance is a blockchain consensus algorithm first introduced by NEM. This consensus aims to determine which nodes are eligible to add blocks to the blockchain network through a process known as “harvesting.”

In the PoI consensus, miners with a high score are given priority to ensure the network’s integrity. However, miners must meet specific criteria before adding a new block. At a minimum, an account must have 10,000 XEM according to the NEM’s basic protocol.

Proof of Importance is a unique mechanism that takes into account an individual’s overall contribution to the security and integrity of the network. 

PoI seeks to overcome limitations in the Proof of Stake model by identifying an account’s overall support for the network.

How Does Proof of Importance Consensus Work?

Fundamentally, this consensus is different from Proof of Work (PoW) or Proof of Stake (PoS), which consider only one aspect. 

PoI emphasizes specific factors that depict the extent of an individual’s participation and contribution to the network.

To fully understand how Proof of Importance consensus works, it is important to comprehend some of its key factors, which are:


Vesting refers to the amount of XEM held in an account as a requirement to participate in the PoI consensus. XEM that has not passed the vesting period cannot contribute to the importance score.


Nodes with a high importance score have a greater chance of performing ‘harvesting,’ which involves adding new blocks to the blockchain and receiving rewards.

Transaction Partners

Another factor is transaction partners, which consider the relationships an account has with other partners in the network. 

An account that interacts more with the other accounts will have a significant impact on its overall score.

Transaction Activity

The number and size of transactions conducted by an account in the last 30 days also greatly influence the importance score. The more transaction activity, the higher the score.

Importance Score

Every miner in the network has an importance score that reflects the contribution and activity of that account in the NEM ecosystem. 

This score is calculated based on a combination of three main factors: vesting, transaction partners, and transaction activity.

Overall, the Proof of Importance consensus is an advanced algorithm that prioritizes each user’s contributions more fairly and transparently compared to the other mechanisms.

Differences Between Proof of Importance (PoI) and Proof of Stake (PoS)

Proof of Importance (PoI) and Proof of Stake (PoS) are two consensus mechanisms used in blockchain networks to validate transactions and achieve consensus.

Both mechanisms share the same goal, which is to maximise network efficiency and security. However, each consensus has differences in how it operates and its underlying concepts.

The PoI consensus focuses more on network activity and broader contributions, while PoS places greater emphasis on cryptocurrency ownership as the primary indicator for incentive selection and security.

Proof of Importance Consensus Pros and Cons

Consensus mechanisms are a crucial foundation in blockchain networks, and each mechanism has its advantages and disadvantages, including Proof of Importance (PoI). 

Here are the Proof of Importance pros and cons that you should be aware of:


  • Proof of Importance encourages active participation and contributions within the network.
  • The PoI mechanism does not solely focus on the quantity of coins in an account.
  • PoI aims to build a fairer and more transparent mining system.
  • High-contributing user activity can help maintain network security and integrity.


  • The Proof of Importance mechanism is more complex and requires more intricate calculations.
  • This consensus is also more vulnerable to external environmental changes.
  • Like many other consensuses, PoI faces challenges at scale, especially in managing and processing data from many active users.


Overall, blockchain technology offers various consensus mechanisms, each with different objectives and advantages. PoI consensus is an intriguing solution, especially when first implemented in the NEM blockchain network.

Proof of Importance introduces a unique approach that measures a user’s contribution to the security and integrity of a network. 

In its efforts to address challenges in the PoS model, the PoI consensus identifies the support provided by accounts to the network as a whole and creates a more inclusive and equitable blockchain ecosystem.

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