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Token swaps allow users swap between any two compatible tokens within Opdex liquidity pools.

For example, a user swaps from USDT to CRS tokens.

Transaction Fees

Token swaps incur a transaction fee, that is set by the market and paid by users as they execute token swaps. Different markets can have different transaction fees from 0% to 1% but the primary Opdex staking market has a fixed transaction fee of 0.3%.

Fees paid from token swaps are collected by liquidity providers and in staking pools, partially to stakers.

See Providing Liquidity and Staking for more details.


When selling SRC-20 tokens, an allowance will need to be approved in order for the transaction to succeed. Allowances are approvals given to smart contracts so they can spend a number of tokens on your behalf, as long as you’ve signed and submitted the transaction.

For example, USDT is an SRC-20 token, so to sell 10 will require an allowance approval of at least 10 tokens.

Price Impact

Price impact is the measurement of how much a swap will impact the liquidity pool’s reserves and underlying token prices.

A higher price impact means that the trade is large and is shifting the underlying token price ratios at a higher rate. The lower the price impact, the more efficient the swap is.

Slippage Tolerance

Slippage tolerance is similar to price impact but is used to buffer added price impact during high volume periods. For example, a swap transaction has an expected price impact of 1% and is submitted. If other transactions front run and change the price by more than 1%, the transaction will fail. Adding a slippage tolerance of 3% would mean that the transaction should still succeed as long as the expected result is less than the 3% change allowed by the user.


Deadlines allow for transactions to fail if they are not executed by a certain block number. For example, if the network is severely congested, transactions may not be mined for a few blocks as they wait to be mined. Adding a deadline allows the transaction to fail safely if if is not mined by the submitted deadline.