Questions tagged [chainlink]

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

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What is the largest number that can be returned from a Chainlink Price Feed?

Is it safe to assume that chainlink oracles have an upper bound on the price feed, eg it fits into uint96, or perhaps a smaller or larger number? It would be great to know the absolute largest number ...
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Do all Chainlink feeds return prices with 8 decimals of precision?

It looks like many Chainlink feed aggregators have 8 decimals of precision: ETH/USD, which returns 140330173736 = $1,403.30173736 BTC/USD, which returns 3696759888474 = $36,967.59888474 I found the ...
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Does Chainlink have an aggregator for its price aggregators?

I need a way to pass an arbitrary ERC-20 token symbol and get a price for it in return. The Solidity interface should look something like this: function getPrice(string memory symbol) external view ...
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I sent Chainlink Link tokens to my ethereum address, how can I recover? [closed]

By mistake I sent Link tokens to my ethereum wallet (kraken) that can not receive them, can I recover those tokens? How? I think I had to swap them before sending, but I am new, and I think I made ...
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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 ...
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Chainlink Price feed Main contract points to Kovan. Why? [closed]

I'm setting up price feeds with Chainlink. https://docs.chain.link/docs/ethereum-addresses#mainnet This page has sections: Mainnet, Rinkeby, Kovan. Under Mainnet.. Clicking a pricefeed takes me to .. ...
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Chainlink `@` syntax or Github url?

I'm going over Chainlink tutorials. Sometime I see Chainlink imports using @chainlink/path/to/contract and other times https://github.com/smartcontractkit/chainlink/blob/path/to/contract. Are ...
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Are there Chainlink Contacts / Nodes for Ropsten?

I noticed on the official docs the networks are Mainnet Kovan Rinkeby Are there Chainlink Contacts / Nodes for Ropsten?
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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 ...
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How to use Chainlink with Truffle/Ganache?

How to use Chainlink with Truffle/Ganache without unboxing a new app? (I have an app already, I don't want to unbox a new one) I'm trying to get the Chainlink price feeds working in local development ...
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1answer
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Chainlink: Data in JSON object not returning

I am using Chainlink to get a value from an API for my smart-contract. I just want to do a simple Get request as described in Chainlink's documentation. Here is the scripte taken from the ...
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Alternatives to get LINK tokens in Ropsten, for RNG

Sorry if this question sounds like very newbie (and maybe it is. I'm developing a Smart Contract which needs a random number generation, and after researching some time it seems that ChainLink VRF ...
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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 ...
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812 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?
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Timed Chainlink oracle call

I have a smart contract that has a price (let's say it gets updated every hour). The price is defined on some website. Using Chainlink oracles, is it possible to get the variable updated only when the ...
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1answer
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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 ...
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How chainlink guarantees the authenticity and accuracy of the data it returns to the smart contract

Given that the oracle and the "request/response" mechanism may be operated by multiple entities, the possibility of data being tampered with during transmission obviously exists. I want to ...
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1answer
25 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 ...
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1answer
35 views

Do miners have to verify blocks?

I want to know whether the bottom layer of Ethereum requires miners to verify blocks? The reason for this problem is that I have been thinking about a scenario of blockchain transaction verification ...
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Can miners choose not to verify transactions in blocks broadcast by other nodes?

When we execute a function on a smart contract, the transaction will be verified by all miners in the entire network before being written to the blockchain. I want to know no matter how complicated ...
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How to interact with a ERC20 / ERC677 token through a smart contract

I'm trying to write a smart contract that can send ERC20 / ERC677 tokens from one user to another. For example send LINK from one address to another. I deployed my contract on the kovan network but it ...
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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 (...
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148 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....
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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 ...
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What is “selector” in ChainLink API call?

I am using the example from chainlink to call an API; however, I am not sure it does. function checkProof(string memory JobLocation, int job_id) public { Chainlink.Request memory req = ...
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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.
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Using Chainlink External Adapters doesn't return anything

Trying to use this Bitcoin Adapter But having some issues specifically with the copyPath argument and the callback arguments. For one, I would like to retrieve multiple parts of the JSON that is ...
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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?
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market.link market-sync for chainlink nodes returning connection error

I'm currently syncing my Chainlink infrastructure with Linkpool's market-sync tool. I have generated a key with their API, and now I'm running the command to sync my node with the market. docker run ...
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Chainlink node not connecting to External Adapter

I'm trying to use the Chainlink External Adapter to connect my contract to Twitter but my node I'm running is seemingly not able to connect to the adapter at localhost:8080 even though the adapter ...
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1answer
70 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 ...
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2answers
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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 ...
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Unable to get response back from chainlink node using truffle console

I am trying to fetch close prices of a property deployed on a server running on a chainlink node. Here's what a snippet from my contract (RealEstateAPIConsumer.sol) looks like : function ...
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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 ...
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Minereum Lucky Draw claims 100% Safe randomness on a smart contract without oracles, is it really possible? [duplicate]

Is the way Minereum Lucky Draw game works really safe 100% onchain RNG and verifiable on smart contract? They claim yes but I would like to know expert technical answer for this, if so, isn't this a ...
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Chainlink not updating variables in Ethereum Smart Contract

I am having a strange thing occuring on kovan network. I am running a smart contract calling my chainlink oracle to request some information. My chainlink oracle responds correctly with the expected ...
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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, ...
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236 views

Error on view function call {'code': -32015, 'data': 'Reverted 0x', 'message': 'VM execution error.'}

I have a view function I'm trying to call on the kovan network with the following code. (You'll need an RPC_URL for the kovan network.) The function is the Chainlink historical price view function. I ...
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1answer
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Unsupported Protocol Scheme When Calling Chainlink Oracle

I have just deployed a smart contract that uses a get request from my chainlink oracle. In my contract it is called as shown below: Chainlink.Request memory request = buildChainlinkRequest(jobId, ...
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175 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: ...
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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 ...
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108 views

Chainlink wrong address [duplicate]

So I recently withdrew funds from binance to my wallet, unfortunately I input a digit wrong in the address and it’s gone elsewhere. Is it possible to recover these funds or the funds are completely ...
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1answer
84 views

TX failed - Bad instruction - Funds not back

I sent some $link amount but TX failed due to Bad instruction error. Tx is https://etherscan.io/tx/0xa45e443c8cf310dbe69ab725358ac2da20afde33442a55ed7df985fe6645057d Have read that failed transactions ...
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1answer
452 views

What is a blockchain oracle?

What is a blockchain oracle for smart contracts? And why is it needed? I've seen a lot of posts about "how do oracles work", and "what is the oracle problem" but I don't understand ...
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2answers
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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 ...
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1answer
182 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 ...
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154 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 ...
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How is the volume for the currency pair accounted for on chainlink's reference data feed?

https://feeds.chain.link/ - link for reference. Let's take the LINK/USD feed for example: From my understanding, the aggregation contract fetches the price of LINK in USD from the node operators who ...
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0answers
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How does chainlink solve the oracle problem? [closed]

I've heard a lot about Chainlink recently -- how Synthetix, Aave and other top Defipulse projects are using them. How exactly does Chainlink solve the oracle problem from a technical perspective?
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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 ...