Bittensor EVM: Examples and Precompiles
Available Precompiles
The following precompiled smart contracts are available on the Bittensor EVM. The source code can be found on GitHub.
Examples
The tutorials in this section cover common EVM workflows on Bittensor, including account management, token bridging, and interaction with precompiles:
- Convert Ethereum (H160) Address to Substrate (SS58): Learn how to convert between H160 and SS58 address formats.
- Bridging and wrapping vTAO: Move native TAO from the Bittensor Substrate layer to the Bittensor EVM and wrap it into vTAO.
- Transfer TAO from Metamask to SS58 Address: Learn how to transfer TAO from your Metamask wallet to your Bittensor SS58 address for a coldkey (wallet) or a hotkey.
- Transfer Between Two H160 Accounts: Learn how to transfer TAO between two H160 accounts.
Standard Ethereum Precompiles
The following table consists of standard Ethereum precompiles with their addresses and description:
| Precompile | Address | Description |
|---|---|---|
ECRecover | 0x1 | Recover the address associated with the public key from elliptic curve signature (ECDSA) |
Sha256 | 0x2 | SHA-256 hash function |
Ripemd160 | 0x3 | RIPEMD-160 hash function |
Identity | 0x4 | Identity function (returns input data) |
Modexp | 0x5 | Modular exponentiation |
Dispatch | 0x6 | Dispatch a runtime call from EVM |
Bn128Mul | 0x7 | BN128 scalar multiplication |
Bn128Pairing | 0x8 | BN128 pairing check |
Bn128Add | 0x9 | BN128 point addition |
Sha3FIPS256 | 0x400 | SHA3-256 hash function (FIPS variant) |
ECRecoverPublicKey | 0x401 | Recover public key from an elliptic curve signature (ECDSA) |
Bittensor-Specific Precompiles
The following table lists of Bittensor-specific precompiles with their addresses, descriptions and links to their respective documentation:
| Precompile | Address | Description |
|---|---|---|
Ed25519Verify | 0x402 | Verify Ed25519 signatures. See Ed25519 Verify. |
SR25519Verify | 0x403 | Verify Substrate SR25519 signatures. |
BalanceTransferPrecompile | 0x800 | Transfer TAO between H160 addresses. see Transfer TAO. |
StakingPrecompile | 0x801 | Staking via msg.value — deprecated, use V2. See Staking Precompile. |
MetagraphPrecompile | 0x802 | Interact with the metagraph (rank, trust, stake, axon). See Metagraph Precompile. |
SubnetPrecompile | 0x803 | Register subnets, get/set hyperparameters . See Subnet Precompile. |
NeuronPrecompile | 0x804 | Register neurons, set weights, serve axon. See Neuron Precompile. |
StakingPrecompileV2 | 0x805 | Full staking with limits, allowances, moves . See StakingPrecompileV2. |
UidLookupPrecompile | 0x806 | Map EVM address → registered neuron UID. See UidLookupPrecompile. |
StorageQueryPrecompile | 0x807 | Manages EVM contracts read access to Substrate chain storage. See StorageQueryPrecompile. |
AlphaPrecompile | 0x808 | AMM pool state, prices, swap simulation. See AlphaPrecompile. |
CrowdloanPrecompile | 0x809 | Create and manage crowdloan campaigns. See CrowdloanPrecompile. |
LeasingPrecompile | 0x80A | Create subnet lease crowdloans, terminate leases. See LeasingPrecompile. |
ProxyPrecompile | 0x80B | Add/remove/execute Substrate proxy relationships. See ProxyPrecompile. |
AddressMappingPrecompile | 0x80C | Convert H160 → Substrate AccountId32. See AddressMappingPrecompile. |
VotingPowerPrecompile | 0x80D | Query per-validator EMA voting power. See VotingPowerPrecompile. |