Token Transfer

Overview

What it means and why it exists

A token transfer moves units of a specific digital token from one holder's recorded balance to another, under the token contract's and network's rules. It may happen inside a smart-contract transaction.

How it works

For a typical ERC-20 token, the sender calls transfer or an authorized spender calls transferFrom. Contract execution updates balances and usually emits a Transfer event. A payment processor identifies the network, authentic token contract, recipient, amount in base units and successful execution before matching the transfer to an order.

Technical details worth understanding

The token symbol does not uniquely identify the asset; lookalike contracts can also emit Transfer events. Some tokens charge transfer fees, rebase balances or implement freezes, so requested and received amounts can differ from simplistic assumptions. Logs are valuable evidence, but state and contract identity must also be considered.

What can go wrong

A confirmed transaction hash can contain several token transfers, including unrelated ones. A failed contract call can consume gas without transferring tokens. Treating a transfer event on the wrong chain or for the wrong contract as payment can falsely mark an invoice paid.

Practical checks

An order-matching rule should include chain ID, contract address, receiving address, amount in base units, receipt success and confirmation stage. Do not match using ticker alone. If a token implements fees on transfer, confirm the net amount credited before deciding whether the invoice obligation was satisfied.

Related concepts

Token, Stablecoin, ERC-20.

Further reading

ERC-20 Token Standard — EIP-20.