Many people see fxMINT offering 0% interest and think it's just borrowing stablecoins for free, but they only look at half the picture.

Yesterday, I went through @protocol_fx's page and mechanism again.
fxMINT indeed doesn't have a continuous annual interest rate, nor does it follow the fluctuating APR based on pool utilization; the cost is directly fixed at the two steps of opening and repayment.
Opening costs 0.5%, and repayment or closing costs an additional 0.2%. Borrow $10k, opening costs about $50, repayment costs $20, totaling a fixed $70.
Whether you borrow for a week or a year, that's all the money.
Short-term turnover might seem expensive, but over a longer period, the costs are gradually spread out.
The core idea is to put most of the costs upfront, so you don't have to guess every day whether next month's interest rate will suddenly spike.
In markets like Aave and Morpho, interest rates are indeed cheap when low, but once the demand for funds rises, APR can also go up.
fxMINT offers you certainty; the main cost is upfront, telling you how long you want to hold the position.
Currently, the protocol's TVL has reached about $152 million, and fxUSD supply exceeds $10k, which also reflects a solid reserve asset value.
The scale is there, but users still need to do their own calculations carefully.
There's also a hidden cost in the collateral assets.
When you collateralize interest-bearing ETH or similar assets, this pledged yield mainly goes into the Stability Pool, and borrowers can't access it.
No deductions are seen in the wallet, but opportunity costs are there.
For long-term holders, this part might be more worth paying attention to than the fixed 0.7% fee.
Plus Ethereum Gas fees—opening, repayment, and rebalancing all require on-chain operations.
The official documentation clearly states that in extreme cases, the protocol may activate temporary borrowing costs for all collateral, which may not be triggered normally but can't be ignored entirely.
Risk protection also has boundaries.
When LTV approaches around 88%, the Liquidation Brake will help adjust debt and collateral to bring the position back to a safer zone, possibly earning a small keeper bounty.
The 95% hard liquidation threshold remains, providing a larger buffer, but extreme risks haven't been completely eliminated.
So I think fxMINT is more suitable for long-term holders of ETH or WBTC, who need stablecoin liquidity and don't want to be repeatedly bothered by floating interest rates.
For short-term high-frequency trading or users especially concerned with capital efficiency, it's best to calculate fixed costs, Gas, and forfeited staking yields thoroughly before making a decision.
Similarly, when borrowing $10k, do you prefer to pay most of the costs upfront, or gamble on the current low rates and hope they don't change in a few months?
With such market volatility, how do you calculate this certainty? What's your take?