Create a Blockchain

Now that we have the genesis file created, we can add a chain to the Subnet that you've created earlier. You will do this by issuing a CreateChainTx on the P-Chain. This will create the P-Chain record for your blockchain and associate it with the Subnet. The CreateChainTx transaction has the following parameters:

• name: The name of the chain
• subnetID: The ID of the Subnet you want to add the chain to
• vmID: The ID of the Virtual Machine that will be used to run the chain
• genesisData: The genesis configuration of the chain

The blockchain will be uniquely identified by the transaction hash of the CreateChainTx transaction.

Virtual Machine (VM) Configuration

When creating your blockchain, you'll need to specify the appropriate Virtual Machine ID:

• For standard Subnet-EVM chains, use the default VM ID: srEXiWaHuhNyGwPUi444Tu47ZEDwxTWrbQiuD7FmgSAQ6X7Dy
• If you're deploying a custom VM (such as subnet-evm with custom precompiles or a hypersdk-based chain), you must specify the correct custom VM ID

Creating Your Blockchain

Use the interactive tool below to complete the blockchain creation process:

Create Chain

Create a new blockchain on your subnet with custom parameters and genesis data.

Chain Name

Subnet ID

VM ID

For an L1 with an uncustomized EVM use srEXiWaHuhNyGwPUi444Tu47ZEDwxTWrbQiuD7FmgSAQ6X7Dy

ConfigurationPrecompile InfoGenesis JSON

Chain Parameters

Enter the basic parameters of your L1, such as the EVM chain ID.

EVM Chain ID

Unique identifier for your blockchain. Check chainlist.org to avoid conflicts.

View registered chain IDs on chainlist.org →

Permissions

By design, blockchain networks are fully permissionless, allowing anyone to transact and deploy smart contracts. However, certain use cases require permissioning to control who can participate in transactions or deploy contracts. On Avalanche, permissioning is an optional feature for Layer 1 blockchains that may or may not be activated, depending on the network's needs.

Tokenomics

Tokenomics in Layer 1 blockchains on the Avalanche network are highly flexible, allowing developers to tailor economic models to their specific needs. Each L1 can define its own native token, specifying its initial allocation, distribution mechanism, and whether it should be mintable for ongoing issuance. This enables a wide range of economic designs, from fixed-supply tokens to inflationary models that support network sustainability.

Transaction Fees & Gas

In addition to the native token, you can also configure the transaction fees (also known as gas fees). This allows Avalanche L1s to define the desired or maximal throughput of the blockchain differently.

Fill in the configuration to generate the genesis file.

Create Chain

Explore moreAvalanche Builder Tooling

When the transaction was submitted successfully, you can head to the P-Chain Explorer for the Fuji testnet and search for the transaction hash to verify the creation of the blockchain.

An endpoint to query the blockchain details via the Avalanche API will be available shortly.