The network

Bittensor runs on a Substrate-based blockchain called Subtensor. The production network is known as Finney; a public test network runs the same software with valueless tokens.

Subtensor does not execute the AI workloads itself. Machine learning inference, data retrieval, and every other task a subnet defines happen on participants' own hardware. What the chain stores is the accounting layer: which accounts are registered where, what scores validators submitted, and how much TAO each participant has earned.

TAO is the network's native token. Its maximum supply is capped at 21,000,000. New TAO is minted every block and distributed to subnets according to how much stake each has attracted, then distributed within each subnet to the participants who earned it.

Block emission follows a halving schedule tied to total issuance rather than to a fixed calendar. The first halving reduced the per-block emission from 1 TAO to roughly 0.5 TAO. Live issuance figures are shown on the analytics page.

The smallest unit of TAO is the RAO, where 1 TAO = 10⁹ RAO. Chain APIs return balances in RAO; TaoScope converts them to TAO before display.

Miners and validators are both called neurons. A neuron is identified by a hotkey and occupies a numbered UID slot on a specific subnet. See Miners and validators.

Coldkeys and hotkeys

Every wallet has a coldkey that holds funds and one or more hotkeys that operate on the network. A hotkey lives on the machine running your miner or validator, so it is exposed by design; the coldkey should stay offline.

Netuid 0 is the root network. It is unlike every other subnet: it has no miners, no task, and no alpha token. Registration there is stake-based rather than burn-based.

Root is where TAO is staked directly. Root stake counts toward a validator's stake weight on every subnet, scaled by a governance-set global TAO weight (0.18 on mainnet at the time of writing). By convention root TAO is priced at 1.0 wherever subnet prices are summed.

TaoScope excludes netuid 0 from subnet listings and miner tooling, because neither registration cost nor miner emission applies to it.

Subtensor produces one block roughly every 12 seconds, which works out to about 7,200 blocks per day. Chain parameters — immunity periods, rate limits, epoch lengths — are all expressed in blocks rather than in seconds, so it is worth memorising the conversions.