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Questions tagged [dapps]

Questions about applications and projects on Ethereum: a decentralized application (dapp) does not require any servers or backends and runs independent on a distributed blockchain.

103
votes
4answers
115k views

What is a DApp?

There are new terms in Ethereum like smart contract. What is a DApp and how is it different from smart contracts?
38
votes
1answer
14k views

What is Whisper and what is it used for?

It's admittedly a very general question, but I've heard "Whisper" mentioned in several places when reading about certain DApps. I understand it allows peer-to-peer messaging of some kind, but what ...
33
votes
2answers
19k views

How does Lisk differ from Ethereum?

Lisk is going to be a full stack DApp development framework for building and distributing decentralized applications. It's currently in the crowdfunding stage but got also added to Microsofts ...
28
votes
1answer
3k views

How do I make my DAPP “Serenity-Proof?”

When Serenity comes around, the network will undergo many changes, some of which may have unexpected consequences on existing Smart Contracts. How can I plan so that I am best prepared to take ...
26
votes
1answer
13k views

What does the keyword “memory” do exactly?

I've been looking through the code of Etherdice and noticed that some variables are declared like ParserResult memory result; and I haven't found the keyword "memory" in any documentation. What I ...
25
votes
3answers
13k views

How to create a Dapp from scratch on Ethereum?

Let's say we have someone who knows about blockchain but who doesn't have any background in blockchain-based application. That person wants to code an ethereum-based Dapp (decentralized application) ...
23
votes
6answers
18k views

web3.eth.contract is not a function when making contract

Whenever I try and make a contract, I get: web3.eth.contract is not a function I'm using this code: const path = require('path'); const fs = require('fs'); const solc = require('solc'); ...
20
votes
3answers
7k views

Are there any public/free nodes to connect a Dapp front end?

I have a small Dapp written in Meteor (client only) that reads some contract and account info from the blockchain. I can deploy my front-end code for free on meteor.com (or a variety of other places),...
18
votes
2answers
12k views

How can we integrate IPFS with ethereum in DApps?

How can integration of IPFS with ethereum be done in DApps? Which parts of a DApp will be on IPFS? Do any examples exist? If a DApp's site is hosted on github, is it not centralized?
18
votes
3answers
5k views

How can DApp developers profit from their work?

Suppose that I make a new, cool DApp that gets very popular. In order to cover development costs and make some profit, I charge users of the app a small quantity which is required to use to app - all ...
17
votes
4answers
13k views

How do I send an arbitary message to an Ethereum address?

How can I send a message to another Ethereum address? And how would that user receiving know that its a message? Is there an Ethereum wallet that will show that I sent a message to that address? And ...
15
votes
1answer
1k views

How should I handle blockchain forks in my DApp?

In the user interface of my DApp, how can I detect that a blockchain reorganization happened and what should I do to update the UI state once the fork is resolved?
14
votes
5answers
2k views

How will regular users be able to use dApps without buying ether?

Requiring users to get ether before they can use a dApp, is too much of a barrier for any kind of mainstream adoption. If dApps offer free ether in a naive way, they can be attacked by Sybils where a ...
14
votes
6answers
9k views

How can dapps work on smartphones?

How can dapps on mobile web browsers interact with web3.js? Is there any tool like Metamask or Mist on the roadmap for mobile?
13
votes
6answers
16k views

Is there a list of DAPPS that are already useable? [closed]

Is there a list of DAPPs that are already useable? Useable means there is an easy accessible GUI, that can interact with the contract.
13
votes
3answers
966 views

What are effective and secure ways of shuffling a deck of cards in a contract?

We want to write a card game in Ethereum. What are effective and secure ways of shuffling a deck of cards in a contract, and dealing them to players? It needs to be done in a way so that no one can ...
12
votes
2answers
4k views

Do users of ERC20 coins need to hold Ether?

Suppose there exists Fancycoin, an ERC20 altcoin which has some functionality implemented by the EVM. It does some nontrivial things that take up gas. According to my understanding, I can receive ...
11
votes
3answers
4k views

What are the best practices to allow user signup and login for a dapp?

From what I have researched, it seems that all of the methods for allowing a user to signup and login for an Ethereum dapp are very cumbersome for the user to use. What are the best practices to allow ...
10
votes
2answers
4k views

Can I run a website 'on' ethereum or only 'with' ethereum?

Do you run a website 'on' ethereum or 'with' ethereum and if the latter, is that only with 'nodejs'?
10
votes
4answers
4k views

What are the different GUI's available for Ethereum?

Are there any easy to use GUI's for Ethereum?
10
votes
2answers
560 views

Is there a tool that creates a basic HTML interface from an ABI?

I am looking for a tool that builds a basic interface for a contract so that I can use this generated HTML as a starting point to build the front end. I am aware that Mist, https://chriseth.github.io/...
9
votes
3answers
1k views

How would stablecoins work on Ethereum?

The idea of a stablecoin in Ethereum is to create a token that is pegged to the price of say $1 USD. What are the main ways of achieving a stable cryptocurrency? What DApps are implementing them and ...
9
votes
1answer
6k views

Create a two-dimensional array in Solidity

How to create arrays addresses using solidity? And we can write two-dimensional array? bool[2][] m_pairsOfFlags; Here is an example of the array, but it does not work
9
votes
2answers
4k views

How to connect a web site to a geth node?

Before the DApp-browser Mist was available, this web3 library seems the way to go on building a bridge from contract to a frontend (web site). But, I cannot get the very basic examples to work. ...
9
votes
1answer
737 views

Is it possible to achieve anonymous mixing through the Ethereum protocol?

Are any developers working on anonymous mixing? Is it achievable through the development of either smart contracts or dapps? Is information leakage reduced or eliminated?
9
votes
4answers
620 views

How will dApps built on ETH deal with the requirements of GDPR?

GDPR expects it's citizens to have the 'right to be forgotten'. A company failing to fulfill this obligation is expected to pay a hefty fine. How will decentralized autonomous communities who store ...
8
votes
2answers
2k views

DApp storage for data other than tranactions?

For the purpose of illustration, say I would like to create a decentralized version of Yelp. A centralized approach would be to have a restaurants table and a reviews table in an Mysql database. In ...
8
votes
1answer
3k views

Unlock account permanently

I have created a dapp where the user can sign a contract using metamask. However, the account that gets the money send to keeps getting locked. Sure, I can manually unlock it, but this is really ...
8
votes
2answers
2k views

Will Ethereum be the Internet 2.0?

I've been following Ethereum since it was announced and I remember that the appeal was that it was "Bitcoin 2.0". While email replaced the post and Bitcoin replaced fiat, Ethereum would replace legal ...
8
votes
1answer
1k views

Are tools like metamask putting decentralization in danger?

Does a tool like metamask, which connects your browser to a public ethereum node to simplify running DApps, put the basic idea of decentralization and trustless blockchain verification in danger? Is ...
8
votes
1answer
12k views

Where can I learn how to develop DApps using the solidity programming language? [closed]

What resources exist to help people learn the solidity programming language and create smart contracts & DApps on Ethereum?
8
votes
1answer
220 views

How many topics can a whisper message have?

I'm thinking in a new DAPP that may use whisper extensively. To evaluate the viability of the DAPP, I need to know if there is a limit on the number of topics that a whisper message can have. I would ...
8
votes
1answer
485 views

Is a DAPP really decentralized? If so, what is decentralized exactly? [closed]

This is kind of a theoretical question with respect to Ethereum DAPPs which I have been trying to learn lately (and of which I will admit I am still woefully ignorant). Basically (using my limited ...
7
votes
3answers
2k views

What are GavCoins and what is their significance?

Quite simply, what are GavCoins and what is their significance?
7
votes
2answers
817 views

Does Ethereum offer encrypted peer to peer communication applications?

I am wondering if Ethereum can be used for encrypted peer to peer communication like delivering encrypted short messages or encrypted data in bulk between two or multiple parties. Are there any ...
7
votes
2answers
10k views

How to build a front end for dApp

I am studying about DApps and Ethereum. I did get the Solidity part but I am confused about the front-end apps. Is it possible that I use web framework like PHP Laravel/Rails for Frontend/Db ...
7
votes
2answers
2k views

Storing private data on the ethereum blockchain

I plan to make an app utilising Ethereum that will store private data about a user. Eventually, I want this data to be accessible by selected users. I have seen conflicting answers & discussions ...
7
votes
5answers
6k views

Trying to connect Mist/Ethereum wallet with testrpc

I need someone who can explain to me, step by step, in simple terms how can I connect the ethereum wallet with the local blockchain. I found the following link: Connect Mist to ethereum-js testrpc ...
7
votes
1answer
1k views

What reputation systems are implemented on Ethereum? [closed]

I'm looking into finding some sort of reputation system on Ethereum. Are there any projects out there already that do this? I found a DEVCON1 video about reputation systems and a few people discussing ...
7
votes
2answers
679 views

How a dapp can call contract functions without running a local full node?

I have developed a contract and a basic dapp. It works on my local environment with my local test node. Now I would like to understand how it can be distributed so that a user doesn't have to run a ...
6
votes
2answers
2k views

How does CryptoKitties track time?

I'm looking at KittyBreeding.sol and see /// @dev Set the cooldownEndTime for the given Kitty, based on its current cooldownIndex. /// Also increments the cooldownIndex (unless it has hit the ...
6
votes
2answers
3k views

What elements of a Dapp's backend are usually stored in a decentralised location?

I'm unclear as to what elements of a Dapp's backend code are actually decentralised. The following link states that a Dapp's backend is stored entirely on the blockchain. However, if I was to create ...
6
votes
1answer
1k views

How should I secure a private key in my dapp?

We are currently building an app that interacts with the blockchain. It needs to be able to make transactions on the blockchain on it's own - for instance to add addresses to a whitelist. This means ...
6
votes
1answer
1k views

How to store and load an IPFS hash as bytes32 in contract written in Solidity [duplicate]

An IPFS hash can be expressed in hexadecimal which is 34 bytes long. Afaik it is most efficient to store fixed length values in a Ethereum contract, thus a maximum of 32 bytes (bytes32). Because the ...
6
votes
2answers
457 views

Customized oracle to access and make changes to data on a cloud service

Although, there is some literature mentioning the possibilities of oracles to supply external data to smart contracts in a blockchain, I am a newb and was wondering whether there is a successful ...
6
votes
2answers
952 views

Ethereum fork of OpenBazaar

Is anyone forking OpenBazaar for Ethereum? OpenBazaar is a Bitcoin marketplace, and the OpenBazaar developers have expressed no interest to integrate any currencies other than Bitcoin.
6
votes
1answer
2k views

How is hosting of a DApp done?

I don't understand how deployment and hosting of a DApp works. My quesitons are: 1.Is DApp's code stored on Ethereum servers or do I have to get my own server and store it there? 2.Do I have to run ...
6
votes
1answer
7k views

Error: VM Exception while processing transaction: out of gas

I am running into out of gas exception while calling this function : contractInstance.createProposal("ADHD", "Foo", 2, {from: web3.eth.accounts[1]}) . I'm super new to ethereum and I would really ...
6
votes
2answers
3k views

Typical architecture of a Dapp with a browser client

I am trying to understand the typical architecture of a Dapp with browser clients. Is the below understanding correct? [Web Browser (end user)] <==> [Server (web application/javascript <==> ...
6
votes
2answers
826 views

How will regular users be able to use dApps without having to install another browser like Mist?

Requiring users to install another browser like Mist, is too much of a barrier for any kind of mainstream adoption. What are potential solutions and how close are they in actual practicality?