Oracles are essential for realizing the economy of blockchains and their decentralized applications. Obviously these are tools that do not foresee the future but allow blockchains to learn the result of an event (from the real world). As such, they make statements about something that has happened in the past.
A forecasting market (PM) can be used to accumulate information about a future event by acting as an oracle. In this case the PM can be used as a source of information on what the oracle can potentially report. However, the oracle will report only the end result of the forecast market.
They provide the final answer of a certain condition set in the smart contract.
For example: "If x band sells 2 million copies, send an Ether to x"
The oracle will answer this question: "Did X band sell 2 million copies?"
If the answer is positive, 1 Ether is sent, otherwise not
Aeternity reaches consensus through a hybrid mechanism between POW and POS, it faces three related problems: scalability, data format and cost.
AE develops a decentralized platform designed to ensure efficient administration, as well as global scalability with off-chain smart contracts, which interface with real-world data by interacting with embedded oracles. In AE there is an integrated oracle system, which can be used to request and access data from various providers.
Aeternity Oracle also published APIs that define the format of the query data as well as the format of the responses. As such, they are very flexible by allowing interaction with smart contracts written with different programming languages.
Aeternity oracles are incorporated into the main chain and nothing needs to be installed. The developers have also launched SuperHero (a platform that allows you to send tips to content creators, a bit like Brave Browser or Publish0x). For more: Aeternity
The REP token uses the Ethereum blockchain, acting as an "oracle" and prediction market peer-to-peer. The goal is to allow anyone, anonymously, to be able to bet on certain events, within a defined time limit, earning tokens if the bet turns out to be right.
Through Augur you can trade stocks or shares from anywhere in the world, without actually having to buy them. A company could also make predictions for events of any other kind (sport, weather, news, politics), creating any type of market to which Augur can respond.
It is a bit different from the other oracles because the more users risk high amounts of capital by betting on a forecast, the more it can be assumed that that forecast is supported by valid elements and is more likely to actually occur within the established time.
How does it work? The user creates a market based on a real event taken from the newspaper (creation phase). Trading begins immediately and other users are free to participate (trading phase). The result of the event is therefore determined by the oracle of Augur (reporting phase). Once the result is determined, traders can close their positions and collect payments (settlement phase).
To certify that the event (subject of forecast) has really occurred, or has not occurred within the established date, will be users of the network, who will be able to receive incentives in tokens for the work done. For more info: Augur
Band is a cross chain data oracle platform that has made a lot of talk about itself especially for a large investment of $ 3 million by Sequoia Capital and for being added to the Cosmos network (50 transactions per second).
Although there are differences, many consider Band to be a fork of Link.
In any case, the staking functionality (over 20% annual return) and the limited supply (100 million) immediately made the price skyrocket. In addition to giving answers on real events, Band is also able to give feeds on token prices.
The token is also supported by Atomic and Trust Wallet. For more info: Band Protocol
This is the most famous oracle and the LINK token exists to create a financial incentive for the network to function well. With an integrated reputation system, a bidding system and a decentralized network that relies on independent oracle service providers, users can make sure their data is reliable as it is verified by multiple independent sources. Scammers are removed and for the system architecture to be honest is more profitable. For network security, priority is given to operators of nodes with a higher reputation.
Oracle services are complicated to build. Real-world data powered by smart contract must be performed ensuring the security and legitimacy of the information. If there is a smart contract that immediately releases relief funds in the event of a large-scale earthquake, you need to make sure that it is indeed a disaster and that the oracle's network has not been compromised. Chainlink as well as being the engine of DeFi (Maker and the creation of Dai) can be added on any platform: special additions have been those on IOTA, Hedera, Zilliqa and Polkadot. But the partnerships don't stop there: Google Clouds, Dapps Inc, Matic Network, Reserve, Swift, Oracle, IOST, Binance, Ethereum Classic, Chilliz, Swipe Wallet, Contentos, Bloom, IrisNet, Tezos, Morpheus Network, BSN, Fleta, Coke. Annual Rise? Almost 300%! For more info: Chainlink
DOS NETWORK (DOS)
DOS supporting multiple heterogeneous blockchains (cross chain interactions), is scalable and low consumption. Dynamic network incentivized by honest participation rewards. Some use cases are for example: flight delay insurance, derivatives / stablecoins (price feed), interest rates, DEX contract distribution across different blockchains (acts as a bridge between transactions), machine learning, 3D rendering , AI, Casino and games. The token is listed on Binance and on Trust Wallet. Thanks to this, in the last year there have been increases of 1006%! (last month 2706%!). For more info: Dos Network
TRB uses a Stacked Proof Of Stake protocol to validate data and a network of miners to retrieve data from smart contracts (so it is a hybrid model that includes both POS and POW). Obviously the rewards provided are to keep the network safe.
Unlike the other oracles, Tellor focuses mainly on the price feed (and not on other off-chain data). It will certainly be one of the reference points for DEFI. For more info: Tellor