Child Hotkey
A child hotkey is a hotkey that a parent hotkey re-delegates a portion of its stake to, so the child can validate on the parent’s behalf on a subnet. The Child Hotkeys documentation describes this as a way for a parent to assign validation responsibility to another key without giving up ownership of the underlying stake (Child Hotkeys).
What It Represents
The relationship routes validation weight, not ownership. A parent hotkey keeps control of its stake while letting the child hotkey act as the validating key for a chosen subnet, so the child carries the parent’s delegated stake weight for validation purposes there (Child Hotkeys, Glossary: Delegate).
For a reader, a child hotkey is best understood as a delegated validation role: it is the key doing the validation work on behalf of the parent, rather than a separate owner of the stake behind it (Staking and Delegation Overview).
Assigned Per Subnet
Child hotkeys are assigned per subnet rather than globally. A parent hotkey can route to one child on one netuid and to a different child, or none, on another, so the arrangement is described against a specific subnet rather than the network as a whole (Child Hotkeys).
This per-subnet granularity lets an operator delegate validation differently across the subnets a parent participates in, instead of forcing one fixed arrangement everywhere (Glossary: Netuid).
Limits on Assigning Child Hotkeys
The child hotkeys documentation sets concrete limits on the assignment. A single parent hotkey can have at most five child hotkeys on a given subnet, and setting or revoking children is rate-limited to once every 150 blocks, roughly thirty minutes. Each assigned proportion must be above zero, and the proportions across all children cannot sum to more than one, so any share left unassigned stays with the parent hotkey (Child Hotkeys).
A Minimum Total Stake Is Required
Assigning children is also gated by how much stake the parent holds. The documentation requires a minimum total stake to set child hotkeys, documented as 1000 TAO-worth of alpha on mainnet and 100 on testnet, and it measures that requirement as the TAO-equivalent value of the parent’s alpha stake summed across all subnets rather than only the subnet where children are being set. A parent under-staked on one subnet can therefore still qualify through holdings elsewhere (Child Hotkeys).
Distinction from Childkey Take
A child hotkey is the key that validates on the parent’s behalf. Childkey take is the rate that key keeps from the resulting dividends, so the child hotkey names the relationship while childkey take names the payout split attached to it (Child Hotkeys, Glossary: Validator Take %).
- Child hotkey — the key that validates on the parent’s behalf.
- Childkey take — the share that key keeps from the routed dividends.
Distinction from Hotkey
A hotkey is the operational key a neuron uses for network actions such as validation and mining. A child hotkey is a hotkey acting in a specific delegated role, validating with stake weight routed from a parent rather than only on its own behalf (Wallets, Coldkeys and Hotkeys in Bittensor, Child Hotkeys).
- Hotkey — the operational key for a neuron’s own network actions.
- Child hotkey — a hotkey validating with stake weight routed from a parent.
Distinction from Coldkey
A coldkey is the ownership key that controls a wallet’s stake and authority. The parent-child hotkey relationship routes validation weight without changing that ownership, so a child hotkey validating on a parent’s behalf does not take over the coldkey’s control of the underlying stake (Wallets, Coldkeys and Hotkeys in Bittensor, Child Hotkeys).
- Coldkey — the ownership key controlling the stake.
- Child hotkey — a delegated validation role that leaves ownership unchanged.
Distinction from Nominate
To nominate is to stake TAO behind a validator hotkey as a supporter. Assigning a child hotkey is a parent-side delegation of validation duty between hotkeys, not a staker placing support behind a validator (Glossary: Delegate, Child Hotkeys).
- Nominate — a staker placing support behind a validator hotkey.
- Child hotkey — a parent routing validation duty to another hotkey.
Reader Boundary
This page defines the concept at a high level. It is not a setup walkthrough and does not report whether a given parent has assigned a child on any subnet, the routed amount, or the configured take. Those are live chain state and operator configuration that should be checked for the specific netuid involved.