Published in


Chainlink: The Bridge to the Blockchain World

Brief History

What is Chainlink?

What is an Oracle?

Chainlink Components: Off-chain and On-chain Systems

  • Reputation contract — keeps track of oracle-service-provider performance metrics
  • Order-matching contract — takes a proposed service level agreement, logs the SLA parameters, and collects bids from oracle providers
  • Aggregating contract — collects the oracle providers’ responses and calculates the final collective result of the ChainLink query
  1. Purchaser specifies requirements that make up the SLA (Service Level Agreement). This include number of oracles, reputation level and query parameters.
  2. SLA is sent to an order matching contract.
  3. Chainlink nodes / oracles that pass the requirements decide whether they would like to bid or not.
  4. When an oracle bids, they also attach the penalty amount that would be lost due to misbehaviour as defined in SLA.
  5. Bid are accepted as long as they are passed within the bid window.
  6. Unchosen oracles get their penalties back
  7. When the finalized SLA record is created, selected oracles are notified.
  8. Oracles perform the assignment detailed in SLA
  9. Oracles report back their results and are fed to the aggregating contract
  10. Aggregating Contract tallies the collective results and calculates a weighted answer.
  11. Validity of each oracle response is reported to the Reputation Contract.
  12. Weighted answer is reported back to the Purchaser.
  13. Purchaser have the option to decide how to deal with outlying data.

Chainlink Sample Use Cases

  1. Money and Finance — the need for reliable data in the Financial sector cannot overstated. Securities smart contracts such as bonds, interest rate derivatives, and many others will require access to APIs reporting market prices and market reference data, e.g. interest rates.
  2. Payment —Given that many banks have data that are very siloed, Chainlink allows smart contracts to connect and interact to these legacy banking system. With Chainlink’s blockchain agnostic nature, it can help bridge payments from one cryptocurrency to another, seamlessly.
  3. Insurance smart contracts — Anybody who has tried claiming an insurance surely knows how much of a hassle it is to prove certain information. With Chainlink, insurance companies can tap into IoT data related to the insurable event in question, e.g.: did the flight you had insurance for arrive on time. Just imagine the surge of new insurance products that insurance companies can offer when they can reliably calculate as well as certify different data points they need.
  4. Enterprise systems — Chainlink can connect legacy database systems to smart contracts. This not only helps improve existing companies but also allows new blockchain projects to easily onboard new clients.
  5. Supply chain —trade smart contracts will need GPS data about shipments, data from supply chain ERP systems, and customs data about the goods being shipped in order to confirm fulfilment of contractual obligations.
  6. Utilities — Imagine being able to track the downtime of your internet service provider and asking for a rebate based on this data. Another possible use case is with the greenhouse/CO2 emission laws. Governments can accurately penalize companies that are causing more harm to the environment with help of blockchain and IoT devices.
  7. Gambling — Smart contracts can provide verifiable, tamperproof outcome probabilities through web APIs for odds. This now allows customers to really know the odds they are playing against instead of just taking the house’ word for it.
  8. Government — With tamperproof records, governments and its citizen can finally achieve a more fair society. From voting, to public personal records such as citizenship, smart contracts can revolutionize society. With this technological capability, the question then shifts to will citizens and government want to implement this?
  9. Authorization and Identity — Tamperproof records will be needed for IP, Signatures, Biometrics and even log in credentials. Chainlink can help verify you and your records reliably.

Link Token Usage

  1. Retrieval of data from off-chain data feeds
  2. Formatting of data into blockchain readable formats
  3. Off-chain computation
  4. Uptime guarantees they provide as operators

Team Members

Votes of Confidence from Industry Partners


  1. Google Cloud announced Chainlink as an official Cloud Partner. As part of this partnership, Google plans to use “Chainlink oracle smart contract” to establish a bridge between Ethereum-based smart contracts and its data warehousing and business intelligence solution — BigQuery.

Token Metrics



Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store