Questions tagged [erc-721]

Relating to ERC-721, the standard for Non-Fungible Tokens (also known as Deeds)

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652 views

How to check Balance & send ERC721 Tokens

I have SPH ERC721 Tokens. How can I check balance like ERC20 and send ERC721 tokens token to Exchange or in other wallet ?
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3answers
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Can an NFT (e.g. ERC721) simultaneously belong to two different entities, say an user Owner, as well as a user Custodian?

For example, on the blockchain say you own a ERC721 Car token at your wallet address, but you want to park it in the ERC998ERC721 top down composable Garage owned by your friend, while still retaining ...
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2answers
85 views

ERC20 and/or ERC721

Consider the following scenario. A person owns a asset called "A". Now the asset is very high valued and unique but you can allow other persons to own a certain part of that asset. EDIT: Ownership ...
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0answers
13 views

gas required exceeds allowance while trying to mintERC721 token using myetherwallet [closed]

I have been working on Udacity Blockchain capstone project. I ran all the tests and deployed the contract on rinkeby test network. However, when i try to mint the token it is giving me above errors. I ...
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2answers
24 views

Where can I find full ERC 721 example programs?

I am building a program with an ERC 721 token. My code runs without using the standard components provided by Open Zeppelin IERC721. Now I want to adapt it to the ERC 721 standard. Unfortunately the ...
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1answer
100 views

ERC721 “Digibles”: different than Bitcoin colored coin concept?

As I understand ERC721 contracts, in particular Cryptokitties, a cryptokitty is not associated with a piece of ETH but rather is just some storage associated with the Cryptokitty smart contract. Is ...
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1answer
44 views

Are there any good ways to express conditional ownership on ERC20 or ERC721 tokens?

I'm currently looking for any good ways to express conditional ownership on tokens. I look into approve function of both ERC20/ERC721 but, it seems that function may be disapproved by the owner and ...
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1answer
380 views

creation ERC721 error: Transaction failed, invalid address,

I would like to learn how ERC721 token works. I found some sample contracts online and tried to use remix and Ethereum Wallet to deploy the contract. The compile was fine but failed in the creation. ...
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1answer
696 views

DeclarationError: Identifier already declared. Two imports import the same ERC721 contract

Im building a contract that uses two contracts that both use the ERC721 zeppelin contract, when I import the two as such: import nonFungableWidthAddedFunctionality1.sol; import ...
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1answer
31 views

ERC-721 - How to avoid that an updatable tokenURI becomes a vulnerability for token trust?

I understand that one can use the tokenURI field to add the address for an endpoint that returns meta data for the given token. Let's imagine we create a unique asset with tokenId = "1" tokenURI = "...
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1answer
13 views

Read and write private variable from child contract

I have a contract MyContract is ERC721. MyContract needs to concatenate a string with an existing token URI using this function: string(abi.encodePacked(_tokenURIs[_tokenId], _URI)); Problem is all ...
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1answer
824 views

Get ERC721 token total supply using web3.js

I created a simple contract which basically does nothing but mints new ERC721 tokens. The solidity code for it is as follows: struct Monster { string name; uint level; uint ...
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2answers
2k views

How to get metadata from ERC721

I'm trying to get Metadata from ERC721 token. Actually I'm trying to do it via ETHERSCAN and blockcypher APIs but I can't find the metadata in the response (like the Picture URL or the IPFS ID) Can ...
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1answer
18 views

Enforcing a limit on ERC721 tokens held by an account

We are providing a Gnosis multisig wallets to our users and a market place where users can purchase/sell/transfer ERC721 tokens with other users. The ERC721 contract will also have a Blacklist ...
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0answers
31 views

Passing constructor arguments from child contract to parent contract

The ERC721 standard contract requires a token name and symbol in its constructor. I have inheritance pattern that looks likes Contract A is B and Contract B is ERC721. If I want to set my token name ...
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1answer
28 views

Why doesn't CryproKitties contract use Enumerable.sol?

I am going through the Cryptokitties code, which does not include the optional Enumerable contract, but the KittyBase contract basically declares equivalent indexation and functions. Why did ...
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0answers
20 views

Possibilities of ERC721 image generation [closed]

What image generation techniques could you suggest for a DApp game that utilizes ERC721? I know that CrypoKitties has a unique DNA sequence and different pieces of the sequence correspond to the ...
0
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1answer
14 views

Identifying ERC-721, ERC-777, & ERC-223 Contracts in the EVM via eth.getTransactionReceipts(), etc

Is there any specific way of identifying ERC-721, ERC-777, & ERC-223 contract events under the EVM, specifically under the eth.getTransactionReceipt() function? I know there's a way for ERC-20 ...
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2answers
52 views

How do you add miner address so that it can mint tokens?

I have ERC721 that I'm making. function mint(address to, uint256 tokenId) public onlyMinter returns (bool) { _mint(to, tokenId); return true; } How can I add an address so that it is able ...
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1answer
17 views

When and where do I set ERC721 tokens' data?

I am currently working on a smart contract to sell ERC721 tokens. I understand that my code should have a function that allows me (the owner) to mint a token and add it to a list which stores all the ...
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1answer
32 views

How to query Cryptokitties metadata from Etherscan

I;m trying to query a Cryptokitties token metadata from Etherscan and I need to give two values: _tokenId (uint256) and _preferredTransport (string). What are possible value for _preferredTransport?
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1answer
228 views

Implementing ERC721 Marketplace

I'm working on a project where I need to implement an ERC721 marketplace. It doesn't work for some reason and wanted to know if I'm doing everything correctly. The way I approached this was: The ...
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1answer
16 views

Does a symbol have to be unique in ERC721? How to find out a unique symbol?

As per the ERC-721 contract on OpenZeppelin, you can create a token with this constructor: constructor(string _name, string _symbol) public {} Does the "_symbol" have to be unique across the ...
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0answers
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Obtaining ERC721 interface IDs

There's a related question here ERC721: Interface ID Registration but I couldn't get the answer I need from there. In the OpenZeppelin ERC721 basic implementation, there's this part: // Base URI ...
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2answers
100 views

erc-721 erc-20 solidity code check effects interaction pattern

Where can one locate a formally verified ERC20/ERC721 solidity code/template that adheres to security design patterns such as check effects interaction patterns?
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2answers
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ERC standard: possible to set upper price limit for NFT?

Let's say I want to create a non-fungible token which represents a ticket to a venue. And I don't want ticket scalpers to buy tickets and resell these tickets for a higher price. It should only be ...
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1answer
65 views

Create multiple tokens for a unique property

here is the idea: we assign a set of unique tokens to a company and then we allow people to buy some tokens and get partial ownership of that company. How can I achieve this? I was thinking of ...
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1answer
28 views

How do exchanges work internally?

Because EVM cannot watch events, we cannot send a token to an exchange and immediately get back some other token (EVM just does not "know" when it was send a token). As far as I understand, this is ...
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2answers
129 views

Unable to invoke smart contract function from Web3j contract wrapper

I've been learning about interacting with smart contracts through Android and the Web3j framework but have run into an issue. I'm trying to mint an ERC721 token and send it to an address but it doesn'...
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2answers
98 views

ERC721 exchange logic

I'm trying to allow NFT holders to sell their tokens by listing prices (ETH) and allow others to buy those listed tokens. I used openzeppelin and succesfully implemented and tested my token creation. ...
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1answer
66 views

ERC721 Metadata and Items

i'm new to ERC721 tokens so this may be a stupid question. Following the Opensea docs and other docs (for example openzeppelin ones), I just create a simple ERC721 token that i called "avatar" which ...
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3answers
86 views

How to issue new ERC 721 tokens for each individuals with different name and symbol

I'm working with an app where different users can create their own ERC721 tokens by passing token, symbol total supply etc. Currently, the code is creating the token, but it has common name only. ...
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1answer
64 views

Difference between ERC 20 and ERC 721 transaction receipt

I want to fetch certain transaction logs from a local ethereum node. For that, I need to identify how to differentiate between ERC 20 and ERC 721 transaction receipts. From what I saw on Etherscan, i ...
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0answers
43 views

ERC721 Token abstract contract or an interface and cannot be deployed

after reading many post i can't found the issues about this Smart contract who compile but it think i miss something about the inheritance and the Abstract contract. This is the SC : // solium-...
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1answer
32 views

Using geth Light Node to detect ERC-721 transactions

Is it possible to use a geth light node to detect incoming transactions executed via ERC-721 contracts? I have experienced being not able to get receipts using getTransactionReceipt in native and ...
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1answer
54 views

Is it possible to check the Thrid party token ( USDT ) within my ERC223 contracts?

I want to check how many tokens are received in my contracts, so that I am able to allocate MY TOKENS to the TOKEN Sender. I tried several ways like approveAndCall, but its not working. I don't ...
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1answer
105 views

How to show inventory tab on etherscan

Sorry, i'm newbie about ERC-721. I have deployed my contract and verified it. https://ropsten.etherscan.io/address/0x677f76d276355c382da948d2476da06cf5dc6219 But I don't see inventory tabs like other ...
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2answers
201 views

Deploy ERC721 tokens to many addresses

How to I transfer many of my ERC721 tokens to many addresses? MyERC721: function mintUniqueTokenTo ( address _to, uint256 _tokenId, string _tokenURI // Store, receipient'...
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3answers
64 views

Using a Non-Fungible token to gain access to a file

Please excuse me, I'm a layperson, not a programmer. At this time is there a way to issue NFT's to be used as a 'key' to gain access to a file on the internet? For example you create and sell an NFT ...
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1answer
44 views

Which token standard should be use to create different tokens for different users?

I have read several differences between fungible and non fungible tokens. It cleared my few doubts though, I have few more remaining. I have requirement to create a platform on which users can ...
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1answer
88 views

ERC721 Transfer Event issue

Looking at the open-zeppelin ERC721 Contract's code, I see that the very last thing that its mint function is doing is call emit on the contract's pre-defined Transfer event. My question is: how do ...
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1answer
142 views

Error: Invalid number of arguments to Solidity function when calling safeTransferFrom function

I want to call the safeTransferFrom function to transfer ERC721 tokens. I am using the following code: var contract = this.web3.eth.contract(JSON.parse(contractabierc721)).at(contractAddress); // ...
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1answer
139 views

Distinguishing erc721 transactions from the response of txlist on etherscan

I am making some erc721 transactions. I can retrieve those transactions using the etherscan api like this https://api.etherscan.io/api?module=contract&action=txlist&address=...
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1answer
155 views

Solidity bytecode not generated despite no errors

When does a compiler fail to generate bytecode for solidity? The code compiles entirely but both remix and solc js give proper abi but empty bytecode. The contract imports ERC721. Solidity contract: ...
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1answer
455 views

Store ERC721 token metadata

I am new to ERC721 tokens so this may be a stupid question. I want to create my own ERC721 which can be integrated with opensea using the metadata, as far as I understand you have to store the ...
2
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1answer
304 views

Calling function from another contract reverts

I've been developing a dApp that needs ERC721 tokens. I have three contracts, a base contract, the one to mint tokens and another one for auctions. The inheritance looks like Base > Token > Auctions. ...
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1answer
40 views

When to use nonfungible tokens and possibility to interchange tokens with different standards

I'm little bit familiar with Blockchain and ERC-20 standard. Now I started learning about ERC-721 and having a lot of confusion. Let's take an example of music artist token platform. Any music ...
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5answers
1k views

ERC721 Error: invalid number value arg=“_tokenId”, coderType=“uint256”, value=

MyERC721: pragma solidity ^0.5.0; import "openzeppelin-solidity/contracts/ownership/Ownable.sol"; import "openzeppelin-solidity/contracts/token/ERC721/ERC721Full.sol"; import "openzeppelin-solidity/...
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0answers
29 views

Difference between method id, event id and ABI signature for event

I am confused as to what is the difference between method id, event id and abi signature. I got the abi signature of a token transfer function according to the following web3js function const ...