What is a token fee?#

A token fee is custom logic in a token contract that changes what happens during a transfer. It is separate from the Centurion Protocol pool fee and from the CTN network cost paid for Newtons.

The three costs to distinguish#

Pool fee: paid within the swap to active liquidity. CenturionDEX v2 uses 0.30%; v3 pools use 0.01%, 0.05%, 0.30%, or 1.00%.
Network cost: paid in native CTN to execute the transaction on Centurion.
Token fee: imposed by the CRC-20 contract and potentially routed, burned, reflected, or otherwise handled according to its code.

A token may apply different logic to buys, sells, wallet transfers, pools, or selected addresses. It may also allow an administrator to change settings after deployment.

How token fees affect swaps#

An AMM normally expects a requested token amount to arrive at the pool. If the token delivers less, the swap may:

Revert during transfer or accounting.
Execute with a lower amount than an interface expected.
Require a specialized route that CenturionDEX does not support.
Produce misleading reserve or balance information.

Liquidity operations can face the same problem. A deposit or withdrawal may lose tokens to transfer logic, and concentrated-liquidity accounting can be incompatible with unpredictable amounts.

How to evaluate a token#

Verify the token contract address on Centurion.
Review current official issuer information and verified source code, when available.
Look for transfer deductions, exemptions, trading switches, blacklist rules, limits, and upgrade controls.
Check CenturionDEX warnings and transaction simulation.
Compare sent and received balances using a small test you can afford to lose.
Avoid the token when you cannot explain its transfer behavior.

Example#

Suppose you request a swap using 1,000 token units, but the pool receives fewer units because the contract redirects part of every sell. The standard quote can become invalid, and the transaction may revert or return less than expected. The exact result depends on how the token and pool contracts interact.

That deduction is not slippage. Slippage describes market movement between quote and execution; a token fee comes from token code.

Common issues#

A buy succeeds while a sell fails.
Wallet-to-wallet transfers work but pool transfers do not.
The deduction changes without a new user action.
A token claims “no fee” while verified code contains adjustable transfer logic.
Removing liquidity returns an unexpected amount.

Stay safe#

Do not grant approval merely to inspect a token. Never connect to an unsolicited “fee checker.” Verify every contract and signature, and never share your recovery phrase, private key, or password.