{{Short description|Cryptocurrency and Ethereum token}} {{Infobox cryptocurrency | currency_name = Chainlink | image_1 =Chainlink Logo (Blue).png | image_2 = | image_title_1 = | plural = Chainlink | symbol = | ticker_symbol = LINK | previous_names = | precision = | white_paper = {{URL|https://chain.link/whitepaper}} | implementations = | initial_release_version = | initial_release_date = | code_repository = {{URL|https://github.com/smartcontractkit/chainlink}} | status = | latest_release_version = | latest_release_date = | project_fork_of = | programming_languages = [[Solidity]], [[GoLang|Go]] | operating_system = Blockchain-agnostic | author = {{ubl|[[Sergey Nazarov (businessman)|Sergey Nazarov]]|Steve Ellis|[[Ari Juels]]<ref name="Whitepaper1">{{cite web |url=https://link.smartcontract.com/whitepaper |last1=Ellis |first1=Steven |last2=Juels|first2=Ari|last3=Nazarov|first3=Sergey |date=4 September 2017 |website=chain.link |language=English |title=ChainLink A Decentralized Oracle Network|format=paper|access-date=8 October 2022 |url-status=dead |archive-url=https://web.archive.org/web/20171006080308/https://link.smartcontract.com/whitepaper |archive-date=6 October 2017 }}</ref><ref name="Caldarelli">{{Cite journal|last=Caldarelli|first=Giulio|date=November 2020|title=Understanding the Blockchain Oracle Problem: A Call for Action|journal=[[Information (journal)|Information]]|publisher=[[MDPI]]|language=en|location=Verona, Italy|volume=11|issue=11|pages=509|doi=10.3390/info11110509|doi-access=free}}</ref>}} | developer = | source_model = Open source | license = [[MIT License]] | block_explorer = | ledger_start = | split_date = | split_from = | hash_function = | issuance_schedule = | timestamping = | merged_mining_parent = | block_time = | block_reward = | circulating_supply = <!-- Requires a reliable source. --> | supply_limit = 1,000,000,000 | exchange_rate = | market_cap = <!-- Requires a reliable source. --> <!-- | website = {{URL|https://chain.link}} -->| website = {{URL|https://chainlinklabs.com}} }}
'''Chainlink''' is a decentralized [[blockchain oracle]] network. Chainlink's token is on [[Ethereum]].<ref name="whitepaper2">{{cite web |url=https://research.chain.link/whitepaper-v2.pdf |title=Chainlink 2.0. The Next Steps in the Evolution of Decentralized Oracle Networks 9 Economics and Cryptoeconomics Staking |last1=Breidenbach |first1=Lorenz |last2=Chacin |first2=Christian |last3=Chan |first3=Benedict|last4=Coventry |first4=Alex|last5=Ellis |first5=Steven |last6=Juels |first6=Ari |last7=Koushanfar |first7=Farinaz|author-link7=Farinaz Koushanfar |last8=Miller |first8=Andrew |last9=Magauran |first9=Brendan |last10=Moroz |first10=Daniel |last11=Nazarov |first11=Sergey |last12=Topliceanu|first12=Alexandru |last13=Tramèr |first13=Florian |last14=Zhang |first14=Fan |date=15 April 2021 |orig-year=2017|website=chain.link |series= |publisher= |agency=research.chain.link |location=[[University of Bern]], [[Cornell Tech]], [[University of California]], [[University of Illinois Urbana-Champaign]], [[Duke University]] |pages=2, 78 |language=English|format=paper |access-date=4 July 2021 |url-status=live |archive-url=https://web.archive.org/web/20210415141430/https://research.chain.link/whitepaper-v2.pdf |archive-date=2021-04-15}}</ref><ref name="Anadiotis-2019"/> The network is intended to be used to facilitate the transfer of tamper-proof data from off-chain sources to on-chain [[smart contract]]s.<ref name="Handbook">{{cite book |last1=Nikbakht |first1=Ehsan |last2=Baker |first2=H Kent |last3=Smith |first3=Sean Stein |title=The Emerald Handbook of Blockchain for Business |date=9 March 2021 |publisher=Emerald Publishing Limited |isbn=9781839821981 |url=https://books.google.com/books?id=jKYgEAAAQBAJ&dq=chainlink+blockchain&pg=PA182 |access-date=8 March 2022}}</ref>
== History == Chainlink was created in 2017 by [[Sergey Nazarov (businessman)|Sergey Nazarov]] and Steve Ellis,<ref name="Anadiotis-2019">{{cite news |last1=Anadiotis |first1=George |title=Chainlink launches Mainnet to get data in and out of Ethereum smart contracts |url=https://www.zdnet.com/finance/blockchain/chainlink-launches-mainnet-to-get-data-in-and-out-of-ethereum-smart-contracts/ |work=[[ZDNet]] |access-date=August 3, 2021 |language=en |date=May 30, 2019}}</ref> who co-authored a [[white paper]] introducing the Chainlink [[Protocol (network)|protocol]] and network with [[Cornell University]] professor [[Ari Juels]] the same year.<ref name="Whitepaper1"/> Chainlink acts as a "bridge" between a [[blockchain]] and off-chain environments.<ref name="Ranica1">{{cite news |last1=Arrowsmith |first1=Ranica |title=Tech, accelerated; 2020 was a hothouse for technology, speeding up the already rapid pace of development and adoption |work=[[Accounting Today]] |issue=34 |date=December 1, 2020 |page=30}}</ref> The network, which services [[smart contracts]], was formally launched in 2019.<ref name="Anadiotis-2019"/>
In 2018, Chainlink integrated Town Crier, a [[trusted execution environment]]-based blockchain oracle that Juels also worked on. Town Crier connects the [[Ethereum]] blockchain with web sources that use [[HTTPS]].<ref name="MIT1">{{cite web |last1=Orcutt |first1=Mike |title=Blockchain smart contracts are finally good for something in the real world |url=https://www.technologyreview.com/2018/11/19/139032/blockchain-smart-contracts-can-finally-have-a-real-world-impact/ |website=[[MIT Technology Review]] |access-date=August 3, 2021 |language=en |date=November 19, 2018}}</ref>
In 2020, Chainlink integrated DECO, a Cornell project co-created by Juels. DECO is described by its authors as a [[cryptographic protocol|protocol]] that uses [[zero-knowledge proofs]] to allow users to prove information is true to a blockchain oracle without revealing [[sensitive information]], such as birth dates.<ref name="Enterprise1">{{cite web |last1=Brett |first1=Charles |title=Chainlink acquires DECO from Cornell |url=https://www.enterprisetimes.co.uk/2020/09/04/chainlink-acquires-deco-from-cornell/ |website=Enterprise Times |access-date=August 3, 2021 |date=September 4, 2020}}</ref>
In 2020, Chainlink launched a proof-of-reserve (PoR) system intended to help cryptocurrency projects and tokenized-asset issuers verify asset backing.<ref>{{Cite book |title=Supply Chain Finance: Mechanisms, Risk Analytics, and Technology |last=Cai |first=Gangshu |publisher=Springer Nature |year=2024 |isbn=9783031561252 |location=Switzerland |pages=479 |url=https://www.google.com/books/edition/Supply_Chain_Finance/lM4gEQAAQBAJ?hl=en&gbpv=1&dq=%22Proof+of+Reserve%22+AND+%22Chainlink%22&pg=PA479&printsec=frontcover}}</ref>
In 2022, Chainlink announced and launched BUILD, a program under Chainlink Economics 2.0 for projects that commit a portion of their fees and incentives to support the Chainlink ecosystem.<ref>{{cite web |title=Chainlink BUILD Program |url=https://chain.link/build-program |website=Chain.link |publisher=Chainlink |access-date=13 January 2026}}</ref>
In 2023, Chainlink introduced the Cross-Chain Interoperability Protocol (CCIP), designed to enable communication between applications across blockchains and traditional financial systems.<ref>{{Cite book |title=RWA Tokenisation in Web 3.0 Era |last=Ba |first=Shusong |publisher=Springer Nature |year=2025 |isbn=9789819676637 |location=Singapore |pages=100 |last2=Wang |first2=Yang |last3=Bai |first3=Haifeng |last4=Zhu |first4=Haokang Thomas |url=https://books.google.com/books?id=Oyh2EQAAQBAJ&pg=PA100&dq=%22Cross-Chain+Interoperability+Protocol%22+AND+%22Chainlink%22&hl=en&newbks=1&newbks_redir=1&sa=X&ved=2ahUKEwj295Tfsb6SAxXjRv4FHf6bMrAQ6AF6BAgJEAM}}</ref> In August 2023, SWIFT reported results from experiments using CCIP with SWIFT messaging to transfer tokenized assets across multiple public and private blockchains.<ref>{{Cite web |title=Connecting blockchains: Overcoming fragmentation in tokenised assets |url=https://www.swift.com/sites/default/files/files/results_report_swift_interoperability_experiments_final_310823.pdf |website=www.swift.com}}</ref> In November 2024, a SWIFT, UBS Asset Management, Chainlink working under the [[Monetary Authority of Singapore]] demonstrated settlement of tokenized fund subscriptions and redemptions over the SWIFT network using Chainlink.<ref>{{Cite web |title=Swift, UBS Asset Management, and Chainlink successfully complete innovative pilot to bridge tokenized assets with existing payment systems |url=https://www.swift.com/news-events/press-releases/swift-ubs-asset-management-and-chainlink-successfully-complete-innovative-pilot-bridge-tokenized-assets-existing-payment-systems |website=www.swift.com}}</ref>
In 2025, the [[United States Department of Commerce]] used Chainlink to publish U.S. government macroeconomic data on blockchains.<ref>{{Cite web|url=https://www.globalgovernmentfinance.com/department-of-commerce-usa-gdp-data-public-blockchains/|title=US Department of Commerce starts posting GDP data on public blockchains|first=Ian|last=Hall|date=August 30, 2025}}</ref> In the same year, Chainlink, J.P. Morgan's Kinexys, and Ondo Finance executed a cross-chain Delivery vs. Payment (DvP) transaction using the Chainlink Runtime Environment.<ref>{{Cite web|url=https://research.grayscale.com/reports/the-link-between-worlds|title=The LINK Between Worlds |date=19 November 2025}}</ref> On October 31, 2025, the [[Hong Kong Monetary Authority]] and the [[Central Bank of Brazil]] carried out a cross-border trade finance pilot using CBDCs and smart contracts. The test connected Brazil's Drex wholesale CBDC system with HKMA's Ensemble platform through Chainlink.<ref>{{Cite web|url=https://www.centralbanking.com/fintech/7974010/hkma-bcb-trade-finance-link-could-be-gamechanger-says-expert |title=HKMA-BCB trade finance link could be gamechanger, says expert |first=Joasia E. |last=Popowicz |date=5 November 2025}}</ref>
== Technology == [[File:SIBOS17 – Chainlink - cleaned.png|thumb|A visual representation of Chainlink's "smart bond architecture"|right]] Chainlink's oracle network allows blockchains to connect to off-chain data and computation resources.<ref>{{Cite web |last=Zhao |first=Yinjie |last2=Kang |first2=Xin |last3=Li |first3=Tieyan |last4=Chu |first4=Cheng-kang |last5=Wang |first5=Haiguang |title=Towards Trustworthy DeFi Oracles: Past, Present and Future |url=https://arxiv.org/pdf/2201.02358.pdf |website=arxiv.org}}</ref><ref>{{Cite web |last=Gansäuer |first=Robin |last2=Ben Aoun |first2=Hichem |last3=Droll |first3=Jan |last4=Hartenstein |first4=Hannes |title=Price Oracle Accuracy Across Blockchains: A Measurement and Analysis |url=https://caaw.io/2025/papers/CAAW25_paper_22.pdf |website=caaw.io}}</ref>
== LINK token == LINK is a utility and governance token of Chainlink. The trade value derived from these tokens is used to pay node operators for retrieving data from smart contracts, and also for deposits placed by node operators as required by contract creators. Tokens can be stored in any ERC-20 wallet, as the ERC677 token retains all the functionality of an ERC-20 token.<ref>{{Cite web|title=FAQ {{!}} Chainlink Documentation|url=https://docs.chain.link/docs/faq/#:~:text=The%20LINK%20token%20is%20an,as%20required%20by%20contract%20creators.|access-date=2021-07-24|website=docs.chain.link}}</ref> Community participants can stake LINK to support the network's cryptoeconomic security.<ref>{{cite book |title=Financial Cryptography and Data Security. FC 2021 International Workshops |date=16 September 2021 |publisher=Springer Berlin Heidelberg |isbn=9783662639580 |url=https://books.google.com/books?id=nI5DEAAAQBAJ&dq=chainlink+token+ERC677&pg=PA116}}</ref>
== References == {{reflist}}
{{Ethereum}} {{Cryptocurrencies}}
[[Category:Ethereum tokens]] [[Category:Decentralized autonomous organizations]]