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Blockchain Oracles, Explained

Last Updated July 5, 2023 8:35 AM
Andrew Kamsky
Last Updated July 5, 2023 8:35 AM

Key Takeaways

  • Blockchain oracles enable smart contracts to leverage real-world data for automation, expanded use cases, transparency, and trust.
  • Different types of oracles exist, each with unique characteristics and advantages.
  • Blockchain oracles retrieve, validate, aggregate, verify, and transmit data from external sources.
  • Prominent blockchain oracle projects include Chainlink, Band protocol, and Augur. 

Understanding Blockchain Oracles

Blockchain oracles are important in connecting blockchain networks with external data sources. They offer a bridge between the on-chain and off-chain worlds of blockchain technology and serve as third-party services that retrieve, verify, and authenticate external data. 

With this bridge smart contracts can utilize real-world data outside the blockchain network that can act as intermediaries, feeding external information to a specific smart contract.

The main benefits associated with oracles lie in their ability to automate processes, expand use cases for smart contracts, and enhance transparency and trust for parties who transact using smart contracts. Oracles ensure data reliability, establish secure connectivity, and address privacy concerns.

Types Of Blockchain Oracles

There are several types of blockchain oracles, each with its own set of characteristics. Here’s a brief on different types of blockchain oracles

Software-based Oracles 

Software-based oracles are computer programs or software applications. They interact with external data sources through Application Programming Interfaces (APIs) or web scraping techniques. Software-based oracles rely on centralized servers, which can introduce a single point of failure and potential security vulnerabilities.

Hardware Oracles

Hardware oracles utilize physical devices or sensors to retrieve data from the external world and feed it into the blockchain. These devices often equipped with built-in cryptographic capabilities ensure data integrity and security. Examples of hardware oracles include Internet of Things (IoT) devices, Radio Frequency Identification (RFI) tags, and smart sensors.

Consensus-based Oracles 

Consensus-based oracles leverage a decentralized network of participants to reach a consensus on the validity and accuracy of external data. By using consensus mechanisms, such as voting or reputation systems, aggregated data from multiple sources may be used to determine the most reliable information.

Decentralized Oracles 

Distribute the oracle functionality across multiple nodes or participants, making the oracle network resistant to single points of failure and censorship. They operate in a peer-to-peer manner, where participants collectively validate and provide data to the blockchain promoting decentralization and security. Projects like Chainlink fall under this category.

How Does Blockchain Oracles Work?

Here’s a comprehensive explanation of how blockchain oracles work:

  1. Data retrieval: Blockchain oracle retrieves information from external sources such as APIs, web services, IoT devices, or traditional databases.
  2. Data validation: After retrieving the data, blockchain oracles validate authenticity, integrity, and reliability. Validation can involve cryptographic techniques, digital signatures, consensus algorithms, or reputation systems to establish trustworthiness.
  3. Data aggregation: Aggregation of data from multiple sources helps ensure data accuracy by minimizing the risk of single-source manipulation or bias. Oracles then consolidate the data into a format suitable for storage and processing on the blockchain.
  4. Data verification: Verification of data ensures consistency with the blockchain’s predefined rules and smart contract conditions. This verification step ensures data conforms to the expected format and specified requirements.
  5. Data transmission: Oracles then transmit data to blockchain networks, making data available for use by smart contracts or DApps.
  6. Security measures: Ensuring data integrity in an effort to prevent tampering of blockchain oracles is vital for security measures and achieved by adopting; trusted data sources, using data encryption, authentication mechanisms, auditing and monitoring and using consensus reputation systems.

Use Cases And Examples Of Blockchain Oracles

Here are some examples of the use cases and benefits of blockchain oracles:

Decentralized finance (DeFi) 

Oracles enable DeFi applications to run with higher degrees of security and efficiency because it fetches external data from multiple premium and authenticated APIs. These APIs are then utilized to source data, which is aggregated and validated to eliminate any potential single point of failure.

One example of an oracle being used in DeFi is the Chainlink  Network’s oracle infrastructure which has served the Trader Joe XYZ  decentralized exchange.

Supply chain management 

Oracles can connect the blockchain network to external systems and data sources, which in turn would connect the blockchain to real-time tracking of goods. This can help prevent fraud, reduce counterfeiting, streamline processes, and improve coordination among supply chain participants. 

By recording supply chain transactions on the blockchain stakeholders may have greater visibility and trust in the process, resulting in improved efficiency and reduced costs. 

Prediction markets 

Prediction markets allow participants to bet on the outcome of future events, such as elections, sports matches, or financial indicators. Oracles become important in determining the outcomes and settling the bets. 

By connecting the blockchain to external data sources, oracles fetch the necessary information and provide it to smart contracts, enabling the automatic execution of payouts based on the results. This eliminates the need for centralized intermediaries and ensures the fairness and integrity of prediction markets.

Challenges And Risks Of Blockchain Oracles

Here are some of the key challenges and risks associated with blockchain oracles:

  • Data reliability: One of the main challenges is the reliability of data obtained from external sources. Data from off-chain sources can be susceptible to errors, manipulation, or malicious intent. Inaccurate or manipulated data can lead to incorrect outcomes in smart contracts decisions or decentralized applications (dApps).
  • Data manipulation: Since oracles act as intermediaries between the blockchain and external data sources malicious actors may attempt to manipulate or tamper with data before it is relayed to the blockchain, leading to fraudulent or undesirable outcomes.
  • Centralization: Centralized oracles possess a significant risk to blockchain systems. When a single oracle provider controls the flow of data, it introduces a single point of failure and undermines the decentralized nature of the blockchain. Centralized oracles can be vulnerable to attacks, censorship, or data monopolies, which can compromise the integrity and trust of the system.

Mitigation strategies for these challenges and risks include:

  • Multiple oracle providers: By using multiple oracle providers, the reliance on a single point of failure is reduced. Using multiple oracles increases data reliability and decreases the risk of manipulation or malicious behavior. 
  • Reputation systems: Implementing reputation systems can help assess their reliability and trustworthiness. Tracking reputation through historical performance and user reviews. Users can choose oracles with higher reputations, reducing the risk of unreliable or malicious data.
  • Decentralized oracle networks: Decentralized oracle networks combat centralization by spreading oracle tasks across multiple nodes or entities. They then use consensus mechanisms to verify and merge data from various sources, boosting reliability and preventing manipulation. 

Prominent Blockchain Oracle Projects

When taking a look at the realm of cryptocurrency some prominent blockchain oracle projects include the following:


Chainlink is an oracle network that helps smart contracts to interact with real-world data and APIs. It has been widely adopted and is known for its verifiable, tamper-proof, and reliable data feeds. Chainlink’s native token is LINK (LINK). 

One of the key features of Chainlink is its decentralized approach, which helps prevent single points of failure and manipulation. The network uses a consensus mechanism to aggregate data from multiple oracles, increasing reliability and reducing the risk of data manipulation. 

Its technology is widely used in DeFi, supply chain management, gaming, insurance, and other sectors where real-world data integration is essential.

Band protocol

Band Protocol is a cross-chain oracle platform that aims to provide access to real-world data on various blockchain networks. It allows developers to create custom oracles and aggregate data from multiple sources. 

Band Protocol’s native token is BAND (BAND) and allows developers to access and integrate real-world data into their applications, such as financial market data, sports scores, weather information, and more.


Augur is a decentralized prediction market platform built on the Ethereum blockchain. It uses oracles to obtain real-world information and settle prediction markets. Augur’s native token is REP (REP) and it leverages the wisdom of the crowd by incentivizing users to report on the outcomes of events accurately. 

This oracle project aims to provide a decentralized platform for forecasting and decision-making, where users may gain insights and make informed judgments based on the collective intelligence of a community.

Regulatory And Legal Considerations

The regulatory landscape for blockchain oracles varies globally, with governments and regulatory bodies adapting their frameworks to accommodate the unique characteristics of blockchain technology. 

While some countries have embraced blockchain-friendly regulations to foster innovation and recognize the legal validity of blockchain transactions, others still face challenges in issuing specific laws tailored to this technology, resulting in legal uncertainty.

Compliance with blockchain oracles poses several challenges, including ensuring data integrity, determining jurisdiction and applicable law, and identifying liability and accountability. Additionally, there are legal implications regarding the legal validity and enforceability of smart contracts reliant on blockchain oracles, as well as the need to comply with existing financial regulations and anti-money laundering laws while reconciling the decentralized nature of blockchain with regulatory oversight.

Future Outlook And Emerging Trends

The blockchain oracles market is ripe for significant growth in the coming years. As blockchain tech continues to gain adoption across various industries, the demand for reliable and secure integration of real-world data into blockchain networks will increase. 

According to market research reports, the global blockchain market is projected  to experience substantial growth. This growth is being driven by the expanding use cases of blockchain technology and the need for trusted external data sources will inevitably grow in tandem.

One notable emerging trend in the blockchain oracles space is the integration of oracles in non-fungible tokens (NFTs). NFTs have gained significant popularity, enabling the ownership and verification of unique digital assets. Oracles play a vital role in providing real-time and verifiable information about the authenticity and ownership of NFTs, enhancing their utility and value.


Blockchain oracles offer benefits such as process automation, expanded use cases for smart contracts, and enhanced transparency and trust. The future outlook for blockchain oracles is promising, with the market projected to experience substantial growth. As blockchain technology continues to advance, the integration of reliable external data sources will become increasingly important for various industries.


What is a blockchain oracle?

A blockchain oracle is a third-party service that connects blockchain networks with external data sources, allowing smart contracts to access real-world data.

What are the benefits of blockchain oracles?

Blockchain oracles automate processes, expand smart contract use cases, enhance transparency, and ensure data reliability for parties entering into smart contracts.

What are the types of blockchain oracles?

The types of blockchain oracles include software-based oracles, hardware oracles, consensus-based oracles, and decentralized oracles.

What are the challenges and risks of blockchain oracles?

Challenges associated with blockchain oracles include data reliability, data manipulation, and the centralization of oracles, which can compromise decentralization and introduce single points of failure.