Questions tagged [oracles]
Oracle is a way of implementing a Smart Contract. Instead of running the contract code directly on the blockchain, the code is executed on some special off-chain entities called oracles which then send the result of the code to the blockchain network with a signature.
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Cross chain smart contract read
I'm trying to read data from Smart Contract B on Blockchain B using Smart Contract A on Blockchain A. For example, Smart Contract B has a function getPlayerAddressesAndBalance that returns data like [[...
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What if lending pool oracle price different from market?
If Aave DAI oracle price stay at $0.90, but actual DAI price on any exchange market is $1.12
What would happen?
Is that mean someone can abuse or exploit Aave because of this price discrepancy?
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I need the address of the oracle service that provides football match results and related pricing information
I am a blockchain developer, and I am currently working on a football betting project. I have completed the development of the relevant contracts on Ethereum. Now, I need an oracle service that ...
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Is it possible to get external data directly from function parameters in solidity?
Blockchain fetches external data through Oracle.
Is it possible for a user calling a smart contract function to upload external data as parameters to the smart contract when calling the function?
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Observations in TWAP Uniswap
In Uniswap v3's TWAP oracle, how often are observations stored in the observations array of each pool (assuming the array's cardinality has been increased several times already)?
Is it on every swap?
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Uniswap v3 TWAP oracle
What's the purpose of secondsAgo, in regards to price accuracy, when using it on observe() to get the tickCumulatives, which you can later use in OracleLibrary.getQuoteAtTick() to get the price of a ...
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Manipulate Uniswap oracles
Is it practically safe to consume from Uniswap v3 spot TWAP oracles on big pairs like WETH/USDC for example?
I mean, I know it's technically possible to manipulate them, but based on this article, it ...
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Chainlink client oracle pricing
I'm currently utilizing Chainlink Oracle to make API calls. According to the documentation, each call on testnet costs 0.1 Link. However, I'm curious about where I can locate pricing information for ...
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Ethereum off chain data
I was wondering if it's currently possible to verify personal or private information on-chain on Ethereum.
Specifically, I would like it to be verifiable that a certain amount of an ETF is held on a ...
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How to get chainlink price feed data for my national currency?
I am new to blockchain currently learning and exploring. I followed Patrick's tutorial and now in order to have hands-on I want to implement a FundMe smart contract but for my national currency ...
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ChainLink ETH/USD price oracle manipulation
I will be concise. I am using ChainLink ETH/USD price feed in my smart contracts. I am ready to deploy the smart contracts so I did a little bit of legwork researching mainstream hacks and one ...
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How to change response from oracle?
I need to test my contract, and to test I need to change data that I recieve from ChainLink Oracle (I get Ethereum price from it). So how can I change price on ETH local for tests using Ganache-Cli or ...
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Oracle For Exchange Defaults
Simple question, is there a trustworthy oracle that can tell me whether an exchange (e.g. binance) defaulted, froze withdrawals, etc.
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Is it possible Randomly generate and privately store data using Chainlink?
I'm working on a social coordination game for the Chainlink Constellation Hackathon. Game mechanics are similar to Mafia, Bang! or AmongUs where roles are assigned at the onset of the game. Roles ...
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Oracle node to connect with the NYSE
Does exist an oracle that it’s able to connect with the NYSE or others stock markets?
If so, could you please tell me which?
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Facing issues while running Chainlink node on XRPL EVM Sidechain network
Basically, I’m trying to run a Chainlink node on XRPL EVM Sidechain network.
Here's the content of the config.toml file that I'm using:
[Log]
Level = 'warn'
[WebServer]
AllowOrigins = '\*'
...
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What happens with Chainlink price feed when L2 sequencer is down?
What exactly happens with chainlink price feeds when an L2 sequencer is down? I know that during this moment transactions can be submitted only through L1 rollup contract and that some users can be ...
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Oracles supporting Polygon Zkevm
Are there any oracles present at the moment supporting smart contracts to securely retrieve data from conventional APIs (not data feeds) through HTTP(S) GET and POST calls.
We have looked into Witnet, ...
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is it necessary to use oracles for Integrating IoT Sensors and smart contract in a Supply Chain Management DApp?
What are the best practices and methodologies for developing a decentralized application (dapp) that focuses on streamlining supply chain management processes through the integration of IoT sensors? ...
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Chainlink Oracle to call API
I have quite some question regarding Chainlink call API.
I made an API and trying to call it from my Chainlink through smart contract. As I linked my API to bridge in Chainlink Operator UI, I try to ...
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Automate Chainlink Get API
I am working on a Parametric Insurance contract, the API call is working as expected, but I need to automate the call to the requestRainData() function. I need to constantly check if the rain MM in a ...
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Another contract is intercepting my contract calls and stealing the funds, what can it be?
This is the code I have, and I deployed to polygon mainnet to test. https://polygonscan.com/address/0x3CC3F39cc2386a8847378F4022917B3bB623BAFD
// SPDX-License-Identifier: MIT
// An example of a ...
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Chainlink vs DEXs & NFT Market prices
I am doing a futures dApp, so I need the price of the underlying assets (all assets are on-chain not fiat). What is the difference between using DEX and NFT Marketplace on-chain prices as oracle and ...
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How to import file with hardhat
I'm following the Alchemy tutorial to build an NFT Marketplace with hardhat. I want to import my smart contract which is an APIConsumer by Chainlink. I can't do it by path since I'm not allowed by ...
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How is consensus reached in a Decentralized Oracle Network?
I understand the deterministic nature of blockchains thus the need for oracles to feed outputs of non deterministic algorithms or API-calls to smart contracts. Using a single node oracle would defeat ...
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Oracle recommendations for stablecoin project
Looking for an oracle to add to my stablecoin project. Want the essentials (decentralized, censorship-resistant, secure mechanics, no multi-sig to control everything).
Any ideas?
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How do I become a reporter for Tellor?
I want to become a reporter for Tellor, but not sure where to begin. Are there any guides or tutorials?
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Chainlink Any API: ETHABIEncode while parsing ABI string: bad ABI specification: unsupported arg type: Trade: bad input for task
I am trying to fetch data from an api which gives multiple response in single call and I am doing this using chainlink external API calls.
In my smart contract i have use array of struct to store ...
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How to get a tweet content using oracle in the smart contract to verify a user
I am trying to verify a user using his social media account. For this purpose, I am creating a registration function where a user needs to post his tweet with his existing EOA address.
How can I ...
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Whitelist and identity tracking of NFT holders
I am working on ERC1155 NFT collection and because of the regulation related to the project I am part of, we are required to allow only certain users to hold the NFT.
For that reason, I want to ...
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Using Chalink oracle for ethereum application
Is using any Offchain data like chainlink oracle is safe as far security is concerned for any ethereum application and how does ethereum ensures that is is safe to use them
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buildChainlinkRequest function of Chainlink is not working properly
The buildChainlinkRequest line no 47 takes 3 parameters:
JobId
Callback Address
Function to callback to
I have smartcontract1 and smartcontract2. The below mentioned function is inside ...
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Address to String in Chainlink Request is giving error?
When i am using
req.add("publicKey","any_public_key_here_as_string");
I have 2 steps mentioned in our job specification
decode_cbor [type=cborparse data="$(decode_log.data)&...
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Please help me with this events error with HttpProvider
I have encountered this error while trying to put my oracle online. Please, help!
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How to specify return value of chainlink MockOracle
I want to test my smart contract locally using chainlink MockOracle how can i specify the returned value and the job Id ?
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Contracts design
I have a project where users deploy their own instances of a contract and those instances need off-chain data through chainlink oracle, what's the best between making the contract has its own request ...
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NFT Price should be set by the algorithm and not by the owner
Just like how the algorithm controls the videos on youtube and not the platform itself.
How can the price of NFT be set by the algorithm (from set of data that keeps changing).
The owner of NFT ...
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How to Implement off chain Keepers for Decentralize Perpetual Exchanges like GMX.io?
I'm attempting to clone gmx.io. I understand most of the on-chain and Dex concepts, but I'm stumped on how to establish an off-chain Keepers they did not opensource the code for that, so could you ...
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Why does chainlink price feed use 8 as decimal in USD pairs? [duplicate]
I am trying to implement Chainlink's price feed in my contract.
I've learned that when using the USD pair, it always uses 8 as the decimal.
I am curious as to why 8 is used instead of 18, is there a ...
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Calling Ethereum view functions from Polygon Smart contract?
Is there some sort of Polygon to Ethereum bridge product that allows you to write smart contracts which call view functions of smart contracts ddeployed on Ethereum Mainnet?
My smart contract looks at ...
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How to get ETH supply from smart contract?
knowing ETH supply from a contract have a lot of use cases in portfolio management. As far as i know there is no native way to query ETH supply from the contract. Is there any provable and trustless ...
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What is the motivation of data updaters in chainlink?
I wondered how chainlink works then I realized its price feeds like ETH/USD are updating periodically.
if I get it right, the nodes have to update data in most blockchains continuously, which costs a ...
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Error when calling already deployed contract: AttributeError: Final argument must be a dict of transaction parameters that includes a `from` field
I'm trying to create a contract that communicates with JIRA API through Chainlink Oracle on the Goerli Network.
The interaction should create a JIRA project, then write some of the returned JSON's ...
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Are there any good/safe use cases for uniswap time weighted average oracle?
Been studying up on uniswap logic, and the time weighted average oracle system. From what I know, on chain oracles have traditionally been susceptible to manipulation attacks, and generally in my mind ...
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How to make data processing out of blockchain?
Is it possible to send data out of chain, process it and feed into smart contract without using centralized services? My goal is to make data processing large data decentralize (without using web2).
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How to Handle token prices for conversion ratio building a oracle contract
I am building a simple Oracle contract to provide conversion ratio to an other contract (a simple DEX), where conversion from token1 to token2 is fine since it equals to 10.
The problem is when ...
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How to fetch IPFS data on Polygon Smart contract?
On a project in solidity, on Polygon/Matic, I need to fetch data from IPFS.
So, an Oracle is mandatory, and I found 2 possible oracles:
Provable (old Oraclize) seems do not accept 2nd layer Polygon.
=&...
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What is the usual workflow among a user, a smart contract and an oracle?
Suppose a user A wants to feed a certain smart contract F with some data d that can be obtained from an oracle O.
What is the usual workflow in the most popular oracle solutions?
I imagine two ...
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How exactly does smart contract consumes data from oracles?
I believe smart contracts cannot make network calls, hence cannot call an external API to get data.
I have read that oracles are ways to provide outside data to smart contracts.
I am now confused on ...
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Chainlink Oracle - What events are emitted and which should i listen to for price updates?
I am looking for events which are emitted by Chainlink oracles when price updates occur. E.g. the Aggregator for ETH/USD price (https://etherscan.io/address/0x5f4eC3Df9cbd43714FE2740f5E3616155c5b8419) ...
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