Home Smart Contract

Smart Contract

Gregory M

By Gregory M

• 20 articles

How do I upload my collection to opensea?

Marketplaces such as Opensea are like Ebay, they are a platform for people to resale their NFTs. The majority of NFT collections first do what is called an "initial sale". An initial sale happens from the collection website where people can buy one or many NFTs, also called minting. Once an NFT is minted, it will automatically appear on marketplaces like Opensea where you can choose to resale your NFTs. In order to do an initial sale, you have to first deploy a smart contract. A smart contract is required because this is where the NFT ownership is stored and can prove you are the owner of which NFT. Your alternative is to upload your entire collection to Opensea manually (it cannot be automated) or deploy a smart contract and airdrop the entire collection to yourself (costly).

Last updated on May 27, 2025

How much does it cost?

AI NFT Collection Generation AI collections are free to generate however you will need credits to generate images. 1 Credit = 1 image generated. Classic NFT Collection Generation The cost to generate an NFT collection will vary based on the size of your collection. Please check this page to calculate your cost. Smart contract deployment The cost to deploy a smart-contract is free (except gas fees). Onemint may apply a mint fee on top of your mint price. See more info here.

Last updated on May 27, 2025

Activate proxy features on a contract

After verifying a contract you need to click on "more options": This will pop up to verify the proxy contract After clicking verify you need to save the changes: After saving the changes this message will appear on screen:

Last updated on May 27, 2025

Which blockchains do you support?

We currently support those networks to deploy your smart contract: - Ethereum - Polygon - Base - Solana - Eclipse - ApeChain - Binance - Turbo - Abstract - Berachain If you need another network, please contact us.

Last updated on May 27, 2025

How much does it cost to deploy a smart contract?

To deploy a smart contract using onemint you will only need to pay gas fees. Onemint does not charge to create a smart-contract.

Last updated on May 27, 2025

Integrate a smart contract to Opensea

Sometimes, Opensea doesn´t automatically recognize a smart contract, so you need to import it manually, here are the steps to follow: 1-Go to "My collections" 2-Select Main or Test Network: 3- Select the blockchain you deployed on a paste the contract address:

Last updated on May 27, 2025

What kind of smart contracts do you have?

Currently our contract uses ERC721a standard and it has all the feautures that we previously had spread between 4 different contract types. This features are: Lazy Mint, Whitelist and Reveal later, in addition to this, we now provide a built in Minting Referral System.

Last updated on May 27, 2025

Contract Management Walkthrough

Here is a walkthrough on what you can on each tab of the Contract Management Page tabs: Mint Settings Whitelist Settings Airdrop Settings Withdraw Settings Marketplace Settings SDK Settings Referrals Settings

Last updated on May 27, 2025

How long does it take for my NFT to appear on Opensea?

There are two ways to import a collection to Opensea: by creating a smart contract or by manually uploading your images. When you deploy a smart contract, Opensea will automatically import the collection after the first NFT has been minted. As more NFTs are minted, they will gradually appear on Opensea. If you see your NFT on Opensea but the image or name is not displayed, you may need to refresh the metadata. To do this, follow the instructions in this article: How to refresh the metadata on Opensea?

Last updated on May 27, 2025

What is gas?

GAS is the cost to perform a transaction on a blockchain network. Gas price is set by miners based on the supply and demand of computational power to process smart contracts and other transactions. EVERY transaction needs to be verified so every transaction will cost gas, contract deployment, minting, buying, selling... Gas fees are measured in GWEI, which denotes a “giga-wei.” One gwei is 0.000000001 ETH. When submitting an order for a transaction, users must indicate a "GAS LIMIT" which is the MAXIMUM amount they’re willing to pay to have their transaction added to the blockchain. Gas will be the same for the deployment of a 100 piece collection, 1000 piece collection or 10000 piece collection.

Last updated on May 27, 2025

How to refresh the metadata on Opensea?

When your contract has been created and NFTs start to appear on your Opensea page after being minted, some of them may show "content not available". To force Opensea to retrieve the image from the metadata for these NFTs, you'll need to refresh the metadata for each one that displays this message. Additionally, when you reveal an NFT, the final image will not be automatically displayed on Opensea. Instead, you'll need to refresh the metadata in the same way to see the final NFT. To refresh the metadata, simply click the button shown in the image:

Last updated on May 27, 2025

How to verify a smart contract?

First go to contract and click "verify": When verifying a smart contract on Etherscan or Polygonscan, those are the options you need to specify: If deployed in 2025, choose v0.8.20+commit.a1b79de6and paris EvmVersion On the next page we set optimisation to "yes" Now we go to step 4 on our dashboard and find the smart contract source code: We copy the contract source code and we paste it on ETH/Poly scan: We now delete the constructor ABI displayed as an example on ETH/Poly scan: And we copy our constructor ABI from step 4 under the smart contract source code: Once all this has been done we can click verify and it will be done. After verifying you can activate the proxy features of the contract to be able to interact with it: Activate proxy features on a contract

Last updated on May 27, 2025

Different Token Standards

In this article we are going to describe ERC 20 tokens / ERC 721 tokens and ERC 1155 tokens: ERC 20: -This is the token standard from all cryptocurrencies -It´s a fungible token, meaning one token can be exchanged for another token with the exact same value (Ex: 1 ETH=1ETH) -Each ERC 20 token is exactly the same ERC 721: -This is a Non Fungible Token, this meaning each token is completely different from the others and there are not two tokens (NFTs) that have the exact same value -They are one of a kind Tokens ERC 1155: -This token can be fungible, semi-fungible and non fungible -Can perform like a ERC 20 token and a ERC 721 token or bouth at the same time -It can be used to create NFTs, tickets, shopping vouchers... ERC 20 and ERC 721 are used to release individual fungible and non fungible tokens, whereas ERC 1155 can release several tokens all at once.

Last updated on May 27, 2025

What can I do from the smart contract management page?

List of values you can change after a contract is deployed: - Cost - Sale on/off - Max per mint (maximun number of nfts someone can mint per transaction) - Max per wallet (maximun number of nfts someone can mint in total) - Presale on/off - Placeholder image List of actions you can perform after a contract is deployed: - Withdraw funds from the contract to the contract owner - Airdrop to a list of addresses - Reveal - Whitelist (List of addresses who can access the presale)

Last updated on May 27, 2025

What is a smart contract?

A smart contract is a program that is stored in the blockchain to facilitate transactions once two ( or more ) conditions are met. In the case of NFTs, the smart contract proves that your wallet (the creator) has the NFTs full ownership and the buyers wallet has the funds to buy that particular NFT and only once this two conditions are made the NFT will be transferred from the creators wallet to the buyers wallet. The smart contract follows simple rules such as "if/when...then..." so for example "IF this person has 1 ETH in their wallet THEN transfer this NFT". This transactions are verified by a network of computers that verifies that this two conditions are met. Once the conditions are met, the smart contract is executed immediately. Given that there is no third parties, the smart contract provides trust so you can see that the information has not been and cannot be altered for personal interest. For the transactions to take place they need to go through a network of computers that all work together to validate each transaction. This is why this transactions need GAS, which is just a term to determine the cost of the transaction to be validated. ( https://help.nft-generator.art/en/article/what-is-gas-il4hxp/?bust=1645715445251 )

Last updated on May 27, 2025

Opt out Opensea Filter for royalties

Our contract now allows you to collect royalties from Opensea trades since we have added their snippet to our contract. By doing this your collection is now only tradable on Opensea and X2Y2 and its blacklisted from all the other marketplaces. To opt out of this and collect royalties from other marketplaces but not from Opensea you will need to go "unregister" from their filter. Step 1: Go to ETH scan go to the "contract" section and "write contract": https://etherscan.io/address/0x000000000000AAeB6D7670E522A718067333cd4E Step 2: Now paste you contract address on step 6 and "unregister" from Opensea´s royalties filter

Last updated on May 27, 2025

How to deploy a smart contract?

Step 1: After generating your NFT collection, access your dashboard, go to the "smart contracts" tab on your project and click "new smart contract" Step 2: Select the collection you have just generated and the blockchain you will be deploying the contract on. In this case its Polygon testnet Step 3: Fill out the information about your collection: Name, description, website and the name of the NFT (ex: Bored Ape #1, CryptoPunk #1...) Step 4: Wait for the collection to upload IPFS Step 5: After the upload has been completed you will generate your smart contract to deploy it Step 6: After the contract has been generated you will have access to its source code and you will be able to deploy your smart contract **Step 7: ** Manage your smart contract

Last updated on May 27, 2025

How to setup a whitelist for your presale?

Step #1 - Deploy your smart contract Setting the whitelist is only available after the contract is deployed Step #2 - List of addresses Prepare your entire list of addresses in a txt file and make sure that you have one address per line and nothing else. Paste the list of address in the "Whitelist" text field and click "Apply". address1 address2 address3 address4 address5 ect Step #2 - SDK (optional) Once the transaction is successful, return to the "Embed mint button" section and copy/paste the new code in your website.

Last updated on May 27, 2025

How do I set the placeholder image?

A placeholder image can only be set after you deploy a smart contract. You will see an option to upload an image from the Smart Contract management page. When you upload your image and save the changes, you need to wait 5-10 minutes until metamask pops up to allow the transaction. While you wait for metamask to pop up, new metadata is being created for the hidden image.

Last updated on May 27, 2025

Does Onemint has have any fees?

Smart-Contracts: We charge the contract owner 0% fee on the primary sale. Minters pay a fee of 0.00069 ETH (or ~$1 on other chains) per mint on top of the NFT mint price you set. Airdrops For airdrops we charge the same fee as the minter fee. The fee is paid by the wallet initiating the airdrop. NFT Collection The fees above do not include the cost of generation the NFT collection (assets and metadata). Refer to our pricing page for NFT Generation cost.

Last updated on May 27, 2025