Oracles

DEP supports several oracle providers to enable smart contracts to access off-chain data and interact with the real world (e.g. price feeds or randomness). These oracles serve as a bridge between the decentralized, trustless environment of blockchain and the centralized, traditional internet.

An oracle is a piece of software that retrieves data from external sources and feeds it into smart contracts on the blockchain. This enables smart contracts to respond to real-world events, trigger automated actions, and execute their intended functions.

List of Oracles

Mainnet

Service	Description	Links & Features
Pyth	Leverages over 70 first-party publishers to publish financial market data to numerous blockchains. They provide data feeds to various assets classes, such as US equities, commodities, and cryptocurrencies.	Developer Docs Pyth Client for Linux Pyth TS client NPM Find audit reports here
Adrastia	Provides a decentralized and permissionless oracle network that is secure, reliable, and easy to use. It uses three types of contracts to provide secure data feeds: Accumulators, Intermediate oracles & Aggregator oracles	DEP data and contract address can be found here
DIA	Enables the sourcing, validation and sharing of transparent and verified data feeds for traditional and digital financial applications. DIA’s institutional-grade data feeds cover asset prices, metaverse data, lending rates and more. Data is directly sourced from a broad array of on-chain and off-chain sources at individual trade-level	DIA feeds are fully customizable with regards to the mix of sources and methodologies, resulting in tailor-made, high resilience feeds DEP Mainnet and Testnet contracts available for use. Update frequency is 2 hrs. Link to DIA's API DIA has a custom feed builder and the supported token pairs are located here the DIA team Discord
Redstone	Offers a radically different design of Oracles catering for the needs of modern Defi protocols	Data providers can avoid the requirement of continuous on-chain data delivery Allow end users to self-deliver signed Oracle data on-chain Use the decentralized Streamr network to deliver signed oracle data to the end users Use token incentives to motivate data providers to maintain data integrity and uninterrupted service Leverage the Arweave blockchain as a cheap and permanent storage for archiving Oracle data and maintaining data providers' accountability Examples of Redstone EVM Connector can be found here
SEDA Network	A multi-chain-native data transmission protocol built on an entirely decentralized foundation. The SEDA network is a Proof-of-Stake on-chain data provision solution that allows anyone to provide and access high-quality data on all blockchain networks	SEDA Chain

How do Oracles work?

   +------------+         +------------+         +-------------+
   | External   |         |   Oracle   |         |  Smart      |
   | Data Source|         | Service    |         | Contract    |
   +------------+         +------------+         +-------------+
        |                       |                       |
        |  API Call             |                       |
        |---------------------> |                       |
        |                       |    Retrieve External  |
        |                       |    Data via API Call  |
        |                       |---------------------->|
        |                       |                       |
        |                       |    Use External Data  |
        |                       |    in Smart Contract  |
        |                       |<----------------------|
        |                       |                       |
        |                       |    Return Result to   |
        |                       |    Smart Contract     |
        |                       |<----------------------|
        |                       |                       |

In this diagram:

• External Data Source refers to a source of data outside the blockchain network, such as a stock market, weather service, or other external API.
• Oracle Service is a third-party service that acts as a bridge between the external data source and the smart contract. It retrieves the data from the external source and provides it to the smart contract.
• Smart Contract is a self-executing contract that is deployed on the blockchain network. It uses the data provided by the oracle to perform certain actions, such as releasing funds or triggering events.
• API Call refers to the request made by the smart contract to the oracle service, asking for the required external data.
• Retrieve External Data refers to the process of retrieving the requested data from the external data source via the API call.
• Use External Data refers to the process of using the retrieved data in the smart contract to perform actions, such as condition checking and state changes.
• Return Result refers to the process of returning the result of the action performed in the smart contract back to the oracle.