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SUBMIT A PRSUBMIT AN ISSUElast edit: Jun 06, 2025

Create a Subnet

This page describes the procedures for creating a new Bittensor subnet on test chain or main chain.

You should first try Creating a Subnet on a locally deployed chain.

Creating a subnet is a major undertaking. You should read up on Understanding Subnets and research existing subnets before planning to create one.

Considerations​

Research existing subnets​

Prospective subnet creators should familiarize themselves with the space of existing subnets.

Burn cost​

The burn cost for subnet creation is dynamic; it lowers gradually and doubles every time a subnet is created.

try it live

Check the burn cost to create a subnet on Bittensor main network and test network:

btcli subnet burn-cost --network finney
btcli subnet burn-cost --network test

A new subnet is not automatically active​

To allow subnet owners to fully set up their subnets and to prevent extraction of emissions to subnet participants before the subnet is contributing to the network, new subnets are inactive and cannot be started for 7 * 7200 blocks (roughly one week) after they are registered. During this time, you can register and activate validators and invite miners into the subnet.

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The subnet and its participants will receive no emissions during the time that the subnet is inactive.

Validating in your own subnet​

You must meet the same requirements for validation as other validators in order to set weights in your own subnet.

One option for subnet owners is to ask one of the root network (subnet 0) validators to parent your validator hotkey as a childkey of theirs. This will lend their stake to your validator, and can help you ensure that your validator maintains a sufficient stake to effectively participate in consensus as well as resist deregistration. See the Child Hotkeys documentation for more detail.

Subnet creation rate limits​

Subnet creations are limited to one subnet creation per 7200 blocks (approximately one per day). The cost to register a new subnet is also dynamic. For these reason, picking the right time to create your subnet requires planning.

Prerequisites​

  • Install the most recent version of BTCLI.
  • Create a wallet.
  • To create a subnet on test chain, your wallet must have sufficient test net TAO. Inquire in Discord to obtain TAO on Bittensor test network.
  • To create a subnet on main network (finney) requires a substantial investment of TAO, depending on current registration cost for new subnets.

Creating a subnet on testchain​

Create your new subnet on the testchain using the test TAO you received from the previous step. This will create a new subnet on the testchain and give you its owner permissions.

Run the create subnet command on the testchain.

btcli subnet create --network test

Output:

# Enter the owner wallet name, which gives the coldkey permissions to define running hyperparameters later.
>> Enter wallet name (default): owner   # Enter your owner wallet name
>> Enter password to unlock key:        # Enter your wallet password.
>> Register subnet? [y/n]: <y/n>        # Select yes (y)
>> Registering subnet...
✅ Registered subnetwork with netuid: 1 # Your subnet netuid will show here, save this for later.

Creating a subnet on mainchain​

Alert: Minimum required TAO

Creating a subnet on the mainnet is competitive, and the cost is determined by the rate at which new networks are registered onto the chain.

Create the subnet​

Use the below command to create a new subnet on the mainchain.

btcli subnet create

Output:

>> Enter wallet name (default): owner   # Enter your owner wallet name
>> Enter password to unlock key:        # Enter your wallet password.
>> Register subnet? [y/n]: <y/n>        # Select yes (y)
>> Registering subnet...
✅ Registered subnetwork with netuid: 1 # Your subnet netuid will show here, save this for later.

Check to see if you can start the subnet​

Use the below command to check whether the subnet can be started.

btcli subnet check-start --netuid x

Where "x" is the subnet ID.

The output will provide you with the block registered and the block at which the subnet can be started, with "blocks remaining" and an estimated time. When this time has passed, the check-start command will return Emission schedule can be started.

Start the subnet​

Use the below command to start the subnet once check-start returns Emission schedule can be started.

btcli subnet start --netuid x