Questions tagged [chainlink]

Chainlink is a decentralized oracle network that enables blockchain smart contracts to securely access off-chain data feeds.

Filter by
Sorted by
Tagged with
11 votes
2 answers
3k views

Is Chainlink's price reference data free to consume?

I was looking at feeds.chain.link and it's not immediately obvious if anyone can tap into all these price feeds without incurring a cost: For instance, I did find the ETH/USD aggregator contract, ...
user avatar
9 votes
2 answers
5k views

What are the costs of using Chainlink to generate a random number using VRF?

I'm doing some research about generating true randomness on the Ethereum blockchain. Of course I came across Chainlink and its VRF solution. Although there are many tutorials around, some from ...
user avatar
  • 888
7 votes
1 answer
2k views

How to import both VRFConsumerBase and ChainlinkClient in same contract

I would like to use 2 of the functionalities of Chainlink, One is VRF and another is making API requests. So I am importing two libraries together. ChainlinkClient.sol and VRFConsumerBase.sol Which ...
user avatar
  • 258
6 votes
1 answer
7k views

What is the cost of using a Chainlink Oracle?

I use the market.link to check available jobs and each job has its own price in terms of link. My question is how many times this fee will be paid? For example: Let's say the API GET request costs 0....
user avatar
  • 989
5 votes
2 answers
828 views

Rules on choosing a Solidity version

Is there a rule on using a specific solidity version? I mostly work with 0.8.7 and they sometimes conflict with some Chainlink or Open Zeppelin contracts since they use either v6 or v7. Should I ...
user avatar
5 votes
4 answers
546 views

How do I withdraw Ether from my Chainlink node

I'm running a chainlink node on mainnet. My chainlink node has an ether balance I would like to withdraw, but I'm not sure how to find the private key for the node wallet. I know that the tempkeys ...
user avatar
  • 153
5 votes
2 answers
1k views

How to get all the historical data from chainlink price feeds?

I wanted to pull the historical data stored by the reference data contracts by chainlink oracles. Since all the data is on-chain, I should be able to view it all? But currently, my contract can only ...
user avatar
5 votes
1 answer
324 views

How is Chainlink decentralized? [closed]

I believe one of the main criticisms of chainlink is that it is not decentralized enough, adding more nodes would be a big step in a positive direction. When I pull data through a node, that node ...
user avatar
4 votes
1 answer
988 views

How often are Chainlink price feeds updated?

I browsed through the Chainlink docs but I couldn't find an answer for how often prices are updated. My understanding is that they have a rule that if the markets become super volatile, they ...
user avatar
4 votes
1 answer
544 views

Does Chainlink store Oracle response for a transaction somewhere on blockchain?

Lets consider an example of transaction lifecycle where a smart contract uses Oracle to get external data ETH/USD price feed that is changed in real-time. Transaction is executed during mining, so it ...
user avatar
4 votes
3 answers
2k views

Brownie Chainlink Import Error VSCode - 'File import callback not supported'

The code seems to have successfully compiled, but VSCode keeps showing this error - "@chainlink/contracts/src/v0.8/interfaces/AggregatorV3Interface.sol" not found. File import callback not ...
user avatar
4 votes
1 answer
403 views

What is the purpose of using a true random number for an NFT?

I don't understand what the purpose of using Chainlink VRF for my NFT's generation is. Why don't I just launch and pick the NFT traits myself?
user avatar
4 votes
1 answer
267 views

How can I protect my Chainlink oracle fulfill method?

Background: I'm writing a contract that inherits ChainlinkClient in order to make an API request via an oracle job: function fetch() private returns (bytes32 requestId) { Chainlink.Request memory ...
user avatar
  • 205
4 votes
1 answer
776 views

Chainlink import causing Truffle console to crash

Related issue on GitHub: https://github.com/trufflesuite/truffle/issues/3329 If I compile my contracts with truffle compile and then open the truffle console with truffle develop then this happens: ...
user avatar
4 votes
1 answer
227 views

What is the verification process of nodes on chainLink?

chainLink is a decentralized system similar to Ethereum, which can help smart contracts execute get requests and return the results. The result of chainLink execution also needs to be verified by ...
user avatar
  • 397
3 votes
2 answers
4k views

Error: missing argument: in Contract constructor

Documenting a solution to this error I received while working on a Chainlink contract: Error Message Error: missing argument: in Contract constructor (count=1, expectedCount=2, code=MISSING_ARGUMENT, ...
user avatar
3 votes
2 answers
897 views

price conversion using chainlink ETHUSD price

I'm storing a product's USD value in contract. mapping (string => uint256) productUSD; For example, if it's $52 I'd store it as productUSD[_product] = 52; Now, when people paying in ETH, I want to ...
user avatar
3 votes
1 answer
578 views

Request multiple random number at once on chainlink VRF

Would it be possible to require more than one random number on the chainlink VRF with only one call to requestRandomness or any other function ? Thank you
user avatar
  • 33
3 votes
1 answer
831 views

How does money randomly dissapear when using ethereum?

I was browsing Hacker News this morning and I came across this thread. I've tried searching for answers, but it still baffles me. If Ethereum is "safe" how can things like this happen?
user avatar
3 votes
1 answer
2k views

Getting LINK for Ropsten network

I'm trying to get LINK for Ropsten. I'm using this faucet: https://ropsten.chain.link/ and, when I've added the new token, I've used this address 0x20fe562d797a42dcb3399062ae9546cd06f63280 (Chainlink ...
user avatar
  • 151
3 votes
2 answers
1k views

ChainLink oracles - are they free to use? Is there an oracle alternative onchain?

How does it work, exactly? We just call this on-chain to get the latest price... but would our contract have to transfer some LINK to it, or what? https://docs.chain.link/docs/get-the-latest-price ...
user avatar
3 votes
2 answers
2k views

How to convert address to string (for use in chainlink request)?

I'm a solidity beginner... This Chainlink.Request memory request = buildChainlinkRequest(clJobId, address(this), this.registerConfirm.selector); request.add("repo", msg.sender); says ...
user avatar
3 votes
1 answer
3k views

How to build a decentralized bridge between two blockchains?

I am trying to build my own custom bridge between Ethereum and Binance Smart Chain so that people can transfer tokens and possibly some other assets from one chain to another and vice versa. For this ...
user avatar
3 votes
1 answer
302 views

How to return a Chainlink API Call to another contract?

I need to call a function that returns the uint value requested by the oracle from another contract function. I am trying the next... but I think I am going by the bad way. Any solution for that? The ...
user avatar
  • 558
3 votes
1 answer
126 views

Is there a mechanism for fair, trustless Chainlink oracle pricing?

When using a Chainlink oracle node that you don't have a formal commercial agreement with, the user pays the node operator in Link tokens, but the node operator bears the cost of transacting on the ...
user avatar
  • 205
3 votes
2 answers
4k views

Generating random number in Solidity without Chainlink

Hello I'm well aware there are plenty of threads around discussing different methods. Just curious and wanted to ask directly here because feel like the situation might be different. Essentially I'm ...
user avatar
3 votes
1 answer
5k views

What is best approach for generating random NFTs?

I am thinking of developing small DApp where user would collect cards (NFT). Each card would have some image and value associated with it. User collects cards by purchasing Pack of Five Cards which ...
user avatar
  • 171
3 votes
2 answers
425 views

How to run Chainlink Project using eth-brownie python

I had installed eth-brownie using command pip install eth-brownie after Brownie installed.I had bake existing Brownie project into a new directory. mkdir MyChainlinkProject cd MyChainlinkProject/ ...
user avatar
3 votes
0 answers
115 views

Advantage of Chainlink's VRF over commitment scheme chain

News Chainlink announced a randomness oracle via VRF: https://blog.chain.link/verifiable-random-functions-vrf-random-number-generation-rng-feature/. Question What is the advantage of an VRF over a ...
user avatar
2 votes
1 answer
1k views

Implementing Chainlink Data in Truffle / Hardhat

What is the easiest way to connect with Chainlink so we can test our dApp locally. Do we have to run a local Chainlink node, or is there any workaround for getting the online data?
user avatar
  • 217
2 votes
2 answers
167 views

Ensuring Only Keepers Can Call My Contract's "performUpkeep" Function

I have a keeper performUpKeep function that is mission critical that only a keeper can call and not some random third party to activate the contract sooner. It appears that the Chainlink keepers ...
user avatar
2 votes
4 answers
1k views

File outside of allowed directories on brownie compile command

trying to import to files from openzeppelin and chainlink in my contract file like so: import "@openzeppelin/contracts/token/ERC721/ERC721.sol"; import "@chainlink/contracts/src/v0.6/...
user avatar
2 votes
2 answers
586 views

Chainlink Beginner Tutorial: call to PriceConsumerV3.getLatestPrice errored: [object Object]

I have followed the steps in the Chainlink docs Beginner's tutorial, as described here: https://docs.chain.link/docs/beginners-tutorial/ Everything appears to work until the last paragraph: Click &...
user avatar
2 votes
2 answers
500 views

Read all historical price data of a Chainlink price feed in Javascript

I want to read all (!) historical price feed prices of a specific Chainlink price feed proxyContract off-chain via Javascript. Based on the docs article I iterate my query, each time reducing my ...
user avatar
2 votes
2 answers
1k views

Why some ERC20 tokens have different Transfer event ABI signature than Transfer(address,address,uint256)?

Looking at ChainLink ABI (using this tool) I see { "anonymous": false, "inputs": [ { "indexed": true, "name": "from", "type": &...
user avatar
  • 31
2 votes
2 answers
59 views

Will a transaction fail if a states from another contract changes before the transaction is confirmed?

I am building an application that you can purchase USDC by paying ETH. I am getting the USDC amount from msg.value(ETH) by directly calling a chainlink pricefeed in my function. function ethToUsdc() ...
user avatar
  • 237
2 votes
2 answers
1k views

I am trying to use chainlink using remix and i followed the chainlink docs

I am facing this issue,What to do now? My Code pragma solidity ^0.6.7; import "https://github.com/smartcontractkit/chainlink/blob/master/evm-contracts/src/v0.6/interfaces/AggregatorV3Interface....
user avatar
2 votes
1 answer
414 views

Chainlink node not initializing, failed to initialize ORM: initializeORM#NewORM: unable to init DB: unable to open postgresql

I am trying to setup a chainlink node on my machine. After setting all the .env variables, I am running the docker command to start the node, cd ~/.chainlink-kovan && docker run -p 6688:6688 -...
user avatar
  • 532
2 votes
1 answer
232 views

Is chain link a stand alone blockchain?

Is chain link a stand alone blockchain or is it a series of smart contracts on the ethereum blockchain?
user avatar
  • 1,393
2 votes
1 answer
322 views

Chainlink Alarm Clock fullfill method never called?

Working with the Chainlink Alarm Clock, my fulfill() method seems to never get called. So for the docs example (below), votingLive is never set back to false after time is up. Everything else works ...
user avatar
2 votes
1 answer
197 views

How to pass argument to Chainlink selector?

I have a mapping with integer keys and struct values. mapping (int => Client) public customers; Each customer has its own proof argument which I am trying to update with a Chainlink API call. Here ...
user avatar
  • 989
2 votes
1 answer
786 views

Does Chainlink decimal change over time?

I am implementing Chainlink in my contract. Should I request the decimals() function periodically, or decimals are static, so I don't have to worry about any decimals change in a specific contract.
user avatar
  • 217
2 votes
2 answers
931 views

Sending token with contract interaction in Remix

I'm aware of using the value field in Remix to include ETH with my function call transaction but is there a way to send another token with my transaction, for example, LINK? Additionally I would like ...
user avatar
  • 87
2 votes
1 answer
300 views

ChainLink VRF number length

Is the length (number of digits) of the number generated by ChainLink VRF always the same? My contract executes modulus operations to get subnumbers of the big number generated, so if it's not the ...
user avatar
  • 43
2 votes
3 answers
2k views

Issue with importing Chainlink & Openzeppelin

Currently trying to run a script and keep running into an error when trying to import chainlink and openzeppelin contracts. Not sure why, I looked at brownie pm list to make sure I have the correct ...
user avatar
2 votes
1 answer
495 views

fulfillRandomness in Chainlink VRF?

After executing the requestRandomness function function getRandomNumber(uint256 userProvidedSeed) public returns (bytes32 requestId) { require(LINK.balanceOf(address(this)) >= fee, "Not ...
user avatar
2 votes
1 answer
115 views

OAuth/BearerTokens in ChainLink

How to add an authentication header for ChainLink API requests? For example, this guide on connecting ChainLink to Twitter API to post a tweet doesn't implement anything of the sort, so how would it ...
user avatar
  • 177
2 votes
2 answers
624 views

Pegging a contracts 'price' to USD?

I have a contract / dapp that is "pay to play". You send X amount of Eth, and you can play. I have a price feed working via Chainlink, but I'd like to peg the Eth amount to USD. Where the ...
user avatar
  • 573
2 votes
1 answer
119 views

Getting data from outside source during a transaction once per day

Is it possible for a token contract to call an oracle to fetch data once every so many hours? Let's say the token was going to use a random number for some decision it was going to make in its ...
user avatar
  • 145
2 votes
1 answer
250 views

Do miners or validators have to pay LINK fees for oracle service?

I will try to ask a question based on the use case. Assume I only use 1 oracle (ignoring the fact decentralization of chainlink oracles) to execute GET call to an API which returns bool information (...
user avatar
  • 989

1
2 3 4 5
7