Horizen Sidechain Solution

Horizen sidechains are a revolutionary scaling solution that enables the connection of bespoke blockchains to the Horizen mainchain.

Horizen sidechains can be created with the programming language and consensus mechanism that best suits your application while retaining the ability to communicate information and value back to the Horizen mainchain’s network of 37,000+ nodes.

Sidechain SDK

Each sidechain is a full blockchain application that requires the implementation of Consensus, network layer, wallet, history, and many other pieces. Most sidechains, beyond their specific logic and data, can be based on the same implementation.

Horizen is providing a Sidechain SDK that addresses most of these aspects and includes all necessary components required for building a blockchain in a single toolbox. This allows developers to focus only on the specific features of their blockchain instead of low-level tasks, making the deployment of a complete blockchain much easier and faster.

Check out the first milestone of our sidechain SDK.

Horizen’s Sidechain SDK will launch in Beta mode in Q2 2020.

Cross-Chain Transfer Protocol


This system relies on the cross-chain transfer (CCT) protocol, which Horizen is providing. All sidechains employ the same unified cross-chain transfer protocol, that is known by the mainchain.

Even though the participants of the CCT protocol will be different for different sidechains, the procedure will be specified by the mainchain consensus protocol. Such unification will allow the system to deploy many sidechains without the need to modify the mainchain consensus protocol for each of them separately.

The CCT protocol defines the structure of the 2-way peg, so it consists of two sub-protocols. The first defines a forward transfer procedure and the other a backward transfer procedure. A forward transfer transmits coins from the mainchain (MC) to the sidechain (SC). A backward transfer transmits coins back from SC to MC.
The most important part of the sidechain construction is the CCT protocol itself, since it defines the overall structure of the communications between MC and SC. The backward transfers are especially important, because the MC, for scalability reasons, does not keep track of the sidechain so is not able to directly verify the validity of a SC to MC transfer.

Sidechain role in the Horizen ecosystem

dApps, Products & Services

Bringing blockchain benefits to life through real-world utility


A revolutionary scaling solution with an open-sourced SDK

Horizen Public Mainchain

A powerful infrastructure fueled by its native cryptocurrency ZEN and a massive node network

Horizen Node Network

The largest and most distributed multi-tiered node network with 40000 active nodes

The latest updates

Horizen Academy

Learn all about sidechains