The idea in one sentence
Bittensor is a blockchain that pays a token, TAO, to participants who produce useful machine-learning output, as judged by other participants, inside markets called subnets. The chain itself does not run models. It runs the accounting: who produced what, who scored it, and how the newly minted TAO is split.
Subnets, miners and validators
Each subnet is a separate market for one kind of digital work. One subnet may pay for text inference, another for image generation, another for scraped and labelled data, another for price predictions. The subnet owner writes the incentive mechanism: what a task looks like and how answers are scored.
Inside a subnet there are two roles.
- Miners run whatever produces the output: a model, a scraper, a pipeline. They answer requests from validators.
- Validators send tasks to miners, evaluate the answers and publish scores, called weights, on-chain. Validators stake TAO, and their weights count in proportion to that stake.
The chain aggregates validators' weights with a mechanism called Yuma Consensus, which discounts validators who deviate strongly from the rest. The result decides how the subnet's share of new TAO is split between miners, validators and the subnet owner. Both miners and validators pay a registration cost, burned in TAO, to obtain a slot, and slots are limited, so poorly performing participants get replaced.
Emissions and the first halving
New TAO is minted every block and distributed across subnets, then within each subnet according to the weights above. The supply is capped at 21 million and the block emission halves at fixed supply milestones, borrowing the shape of Bitcoin's schedule. The first halving took place in December 2025, cutting the per-block emission in half. Later halvings follow the same rule.
The chain runs on Substrate, the same framework as Polkadot. Blocks are roughly twelve seconds apart, transaction fees are small and paid in TAO, and TAO can be staked to validators or, since 2025, into subnets.
dTAO: subnet tokens since February 2025
Until early 2025, how much emission each subnet received was decided by votes from validators on a root network. dTAO, activated in February 2025, replaced that with a market.
- Every subnet has its own token, usually called alpha, paired against TAO in an on-chain pool.
- Staking into a subnet means swapping TAO for that subnet's alpha through the pool. Unstaking swaps it back.
- Emission to each subnet is proportional to the price of its alpha in TAO, so participants who stake into a subnet are voting for it with capital.
Two consequences for a holder. First, staking into a subnet is no longer a risk-free way to earn yield; you hold a subnet token whose TAO price moves with demand, and unstaking through a thin pool has slippage. Second, subnets have direct financial incentives to attract stake, which is exactly the situation in which marketing outruns output.
Checking an 'AI crypto' claim
Bittensor is often described as 'decentralised AI'. Whether that is true for any given subnet is checkable. Ask:
| Question | Where to look |
|---|---|
| What does the subnet actually pay for? | The subnet's incentive code and documentation |
| Is anything using the output? | A product, API or dataset you can try yourself |
| Are miners doing real work or gaming the scorer? | Subnet explorers, validator reports, community audits |
| How concentrated is stake and emission? | On-chain stake per subnet and per validator |
| Has the mechanism changed recently? | The subnet's own changelog |
A subnet with a large alpha price and no product is a bet on future output. A subnet with a working service and modest emission is the opposite. Both exist; the token price alone does not tell you which one you are looking at.
Wallets and addresses
A Bittensor address is a Substrate ss58 address and starts with the digit 5. Two keys matter:
- The coldkey holds funds and is used to send, receive and stake. This is the one you protect.
- The hotkey is used by a miner or validator to operate on-chain and should never hold more than it needs.
If you only hold and swap TAO, you use a coldkey and can ignore hotkeys. Wallets that support Bittensor include the official Bittensor Wallet browser extension and Substrate wallets such as Talisman and SubWallet; the command-line tool btcli is what operators use. Verify that a wallet is the official build before entering a seed; imitation extensions have been a recurring problem in this ecosystem.
How to swap TAO without an account
There is a direct TAO to USDT ERC-20 pair for selling, and TAO is in the swap form for buying from other listed assets.
Selling TAO:
- Open the TAO to USDT ERC-20 pair, enter the amount and your Ethereum 0x address.
- Click Swap now. You get a unique TAO deposit address and a status page with no login.
- Send exactly the amount shown from your coldkey. The floating rate locks once the deposit is confirmed.
- USDT arrives on Ethereum as an ERC-20 transfer. To move it later you need ETH for gas in the same wallet, so either keep some or swap a little USDT into ETH.
Buying TAO:
- Pick a listed asset as the source and TAO as the destination in the swap form.
- Paste your ss58 address starting with 5 as the destination and send the deposit to the address shown.
- TAO is paid out to that address once the deposit is confirmed.
The cost is the network fee to send the deposit plus the spread and payout network fee built into the quote; the pair page shows the all-in cost for a sample amount.
Mistakes to avoid
- Sending to a hotkey. A hotkey is an operational key; use your coldkey address for payouts.
- Confusing TAO with alpha. A subnet token is not TAO and cannot be sent to a TAO address or swapped here.
- Treating staking as fixed income. Under dTAO, staking is a position in a subnet token.
- Receiving USDT ERC-20 with no ETH. The USDT is safe, but the wallet cannot move it until you add gas.
- Trusting the label. 'AI' in a subnet name is a claim; the output is the evidence.
TAO → USDT (ERC-20)
USDT (ERC-20) → BTC