Transfer

Event v101 → current #2

Emitted when tokens are transferred between accounts.

Useful for: walletsexchangesanalyticsdevelopersstakers

The Big Picture

This is the fundamental 'money moved' event. Every TAO transfer between accounts emits this event. It's the building block for payments, tips, exchange operations, and any movement of liquid (unstaked) TAO. Wallets and exchanges monitor this constantly.

Why This Matters

When someone sends you TAO, or you send TAO to someone, this event proves it happened. The from/to/amount fields tell the complete story. Exchanges use this to credit deposits; wallets use it to show transaction history.

Example Scenario

You receive a payment of 10 TAO. Balances.Transfer fires with from: sender's address, to: your address, amount: 10000000000 (in RAO, = 10 TAO). Your wallet detects this event and shows 'Received 10 TAO from [sender]'.

Common Questions

Why is the amount so large?: Amounts are in RAO (the smallest unit). 1 TAO = 1,000,000,000 RAO. Divide by 10^9 to get TAO. This avoids decimal precision issues in blockchain math.
What's the difference between Transfer and transfer_keep_alive?: transfer_keep_alive refuses to empty your account (keeps existential deposit). transfer_allow_death can empty it completely. Both emit Balances.Transfer.
Can transfers fail silently?: No. If you see Balances.Transfer, the transfer succeeded. If it failed, you'd see ExtrinsicFailed instead, with no Transfer event.

Use Cases

Track incoming and outgoing TAO payments
Build payment notification systems
Monitor exchange deposits and withdrawals
Track fund flows across the network

How to Use This Event

→ Subscribe to your address for payment notifications
→ Monitor exchange hot wallets for deposit detection
→ Index all transfers to build payment analytics
→ Track whale movements and fund flows

From Chain Metadata

Transfer succeeded.

Triggers

Emitted by

transfer_allow_death transfer_keep_alive transfer_all force_transfer transfer

Preconditions

Sender has sufficient balance
Transfer won't kill sender (or transfer_allow_death used)
Recipient will meet existential deposit

May fail with

InsufficientBalance ExistentialDeposit KeepAlive

Effects

Storage Modified

Account TotalIssuance

Postconditions

Sender balance decreased by amount
Recipient balance increased by amount

Side Effects

May trigger NewAccount if recipient is new
May trigger KilledAccount if sender balance goes to zero

Event Data

#	Name	Type	Description
0	from	AccountId	Sender account (hex -> SS58)
1	to	AccountId	Recipient account (hex -> SS58)
2	amount	u64	Transfer amount (RAO) (RAO -> TAO (/ 10^9))

Code Examples

import { ApiPromise, WsProvider } from "@polkadot/api";
import { stringCamelCase } from "@polkadot/util";

const provider = new WsProvider("wss://entrypoint-finney.opentensor.ai:443");
const api = await ApiPromise.create({ provider });

// Subscribe to Transfer events
api.query.system.events((events) => {
  events
    .filter(({ event }) =>
      event.section === stringCamelCase("Balances") &&
      event.method === "Transfer"
    )
    .forEach(({ event }) => {
      console.log("Transfer:", event.data.toHuman());
    });
});

On-Chain Activity

Emission Frequency

●●●●●○ Dominant 5M–50M emissions

Core protocol operations, high volume

#10 most emitted event

As of block 7,429,232

Runtime Info

Pallet Index: 5
Event Index: 2
First Version: v101
Current Version: v393

Back to Balances Events