13
votes
Accepted
Is it secure to read USD / ETH rate from exchanges directly without using price oracles?
TL;DR: It is not secure to read pricing information from an exchange or other protocol. Always use a decentralized oracle.
You're setting yourself up to be hacked when building smart contracts. ...
- 12.4k
11
votes
Accepted
How can I get USDT/USDC for Polygon Mumbai Testnet?
I've gotten some assets for polygon mumbai here: https://faucet.paradigm.xyz/
Including DAI/wETH/MATIC.
Should be able to trade those for USDC/USDT. From a quick search, can trade for USDT on Mumbai ...
- 752
5
votes
Optimism L2 USDC or USDC.e
Eh, it's a bit of a mess as of right now, so whether to use USDC or USDC.e depends on your objective.
Explanation:
Current USDC.e is the original bridged version on Optimism that used to be called ...
- 1,178
5
votes
Good Ropsten USDC faucets?
Go to Compound Finance
https://app.compound.finance/asset/
Change the network to Ropsten in your Metamask
Click on the USDC market
Click on Withdraw and then Faucet
See similar answer for DAI: ...
- 1,015
4
votes
Accepted
Where to find and how to get Kovan USDC testnet tokens
https://staging.aave.com/#/faucet. You just connect with your Metamask wallet on Kovan testnet and select USD Coin. You will be prompted to accept the metamask transaction and after you will receive ...
- 351
3
votes
Accepted
Approving USDC spending using proxy contract
With proxy contracts, you have the proxy contract and the implementation contract. First off you have your terminology a little mixed up.
In this case, the proxy contract would be ...
- 997
3
votes
How can I get USDT/USDC for Polygon Mumbai Testnet?
The only way I found so far is (that still works):
Create a developers account on Circle (here) and get an API key
Use their demo app to add balance to your account available here or use their ...
- 31
3
votes
How to get TEST USDC on Avalanche FUJI Testnet
What I did was to create a mock USDC contract. Just a simple IERC20 with 6 decimals and used that for testing purposes.
- 239
2
votes
Accepted
Why USDC interest rates are so high compared to USD interest rates?
The borrowers on DeFi lending pools cannot lend from a bank, because of technical risk (hacks) and the nature of the business. The borrowers are mostly cryptocurrency traders. However, they can still ...
- 23k
2
votes
Good Ropsten USDC faucets?
Try Uniswap protocol. Go to the https://app.uniswap.org/#/swap (you'll need metamask or similar tool).
The idea behind this is that you swap ETH for some other token. You can specify the contract ...
- 143
2
votes
Accepted
How much UNI can I earn if I become a liquidity provider?
You can only addequal USD value pair to a pool, let's see 1000 USDC/2.6 ETh (Eth price 384), the daily return is about 1.8% at the moment, based on the pool size of 25m for this pool, with daily ...
- 36
2
votes
Accepted
What is the sequence of events when a transaction is made on Uniswap?
The price is not locked in. The swap rate you receive will be the rate of the pair at the time that your transaction is included in a block. However, the Uniswap protocol has a "slippage" ...
- 18.3k
2
votes
Is it secure to read USD / ETH rate from exchanges directly without using price oracles?
You can use the USDC/ETH rate e.g. on Uniswap v2 pools. You can calculate the token price from reserve ratio of tokens on this pools, because reserves follow simple XY liquidity model. Range based ...
- 23k
2
votes
Accepted
How do I withdraw/transfer USDC back into my wallet from my copied/created contract?
Someone teaching you on youtube how to make a front running bot that can make you 5 eth a day??? If it's too good to be true, it's because it isn't true. It's a scam.
There is no way to get your USDC, ...
- 2,000
1
vote
Why is the ETH value of this transaction zero?
The token being transferred was created by address 0xe13...562 6 days ago on December 9th, 2024, and is named USDC-ERC20.
It isn't the real USDC token from Circle so it doesn't have any real value, ...
- 1,735
1
vote
How does USDC ever lose its peg?
Because USD/USDC trade involves other matters besides collateral
Withdrawal fees
Transfer fees
Inelastic supply and demand for USDC
- 23k
1
vote
Accepted
Handle exchanging 6 Decimal Token to 18 Decimal Token (eg. USDC to ERC20)
Since in your case, the token is of 18 decimals, suppose you want to buy 10 tokens so the amount that you would enter is 10 multiplied by 10^18 which means 10000000000000000000. Alternatively you can ...
- 1,012
1
vote
Accepted
USDC EIP-3009 Ethereum and Polygon code mismatches
Polygon USD Coin (PoS), USDC, or any of bridged Polygon tokens are not EIP-3009 compatible.
They have transferWithAuthorization function, but you need to use a different EIP-712 message for signing. ...
- 23k
1
vote
USDC EIP-3009 Ethereum and Polygon code mismatches
Where do you include the TRANSFER_AUTHORIZATION_TYPEHASH in the ethers side of things, like for creating the signature.
There's the struct, that contains the relevant data about the user interaction, ...
- 11
1
vote
How can I get USDT/USDC for Polygon Mumbai Testnet?
Use https://www.buildbear.io/ You can fork Ethereum, Polygon, Binance, Optimism, Arbitrum, Fantom, and Avalanche chains, allowing you to test your projects on the actual Mainnet state.
- 11
1
vote
Is it secure to read USD / ETH rate from exchanges directly without using price oracles?
Patrick gave a great answer on why an exchange based oracle is bad, but unfortunately LINK is pretty far from trustless. Depending on the size of your contract or what you're using it for, an AMM ...
- 3,920
1
vote
Where to find and how to get Kovan USDC testnet tokens
Kovan is deprecated along with Rinkeby and Ropsten. Therefore, make sure to get Goerli testETH from a reliable faucet (like https://goerlifaucet.com) b/c there's lots of scam out there. Uniswap is a ...
- 308
1
vote
How to send USDC through geth CLI?
You need ether to pay the transaction's fee. The USDC contract uses 6 decimals so to transfer 100 USDC the amount parameter should be 100 * 1000000.
- 30.3k
1
vote
Accepted
Good Ropsten USDC faucets?
A dYdX API endpoint can be used to request testnet tokens.
POST v3/testnet/tokens
Refer to the documentation for more details.
- 26
1
vote
Accepted
Best way to conver ETH to a layer 2 ETH or Wrapped ETH to convert to USDC or USDT?
I don't think there is a shortcut. If you want to convert asset A to asset B the cheapest option is usually to convert it directly.
Layer 2 is not meant for trying to save gas fees on Layer 1. Layer 2 ...
- 30.2k
1
vote
Usdc bep20 from trust wallet sent to usdc erc20 on metamask
i did the same thing today. i sent USDC from trust wallet to my ETH metamask wallet and it never showed. I found the bscscan tx link in my trust wallet USDC history. i clicked that and copied the &...
- 11
1
vote
Tokem ERC20 eth accept payament usdt
Work in the following order.
Use the USDT contract's approve function to allow the user USDT to be sent to your contract address.
Write a payment function in your contract. The user calls this ...
- 306
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