Tezos is an open-source blockchain that can execute peer-to-peer transactions and serve as a platform for deploying smart contracts. The native cryptocurrency for the Tezos blockchain is the tez (Abbreviation: XTZ; sign: ). The Tezos network achieves consensus using proof-of-stake. Tezos uses an on-chain governance model that enables the protocol to be amended when upgrade proposals receive a favorable vote from the community.[1] Its testnet was launched in June 2018,[2] and its mainnet went live in September 2018.[3]

Prevailing tezos logo
PluralXTZ, tez
Original author(s)Arthur Breitman, Kathleen Breitman
White paper"Tezos – a self-amending crypto-ledger"
Initial release30 June 2018 (4 years ago) (2018-06-30)
Latest release13.0 /
Code repositorygitlab.com/tezos/tezos
Development statusActive
Written inOCaml
Source modelOpen source
Timestamping schemeProof-of-stake
Block rewardꜩ40
Block time30 seconds (since Granada update)
Block explorertzstats.com


Circulating supplyꜩ888,184,894 (est. May 2022)
Exchange rateUS$2.10 (25th May 2022)
Market capUS$1.86 Billion (25th May 2022)


Tezos, first proposed in 2014, was created by husband-and-wife team Arthur and Kathleen Breitman, and the Tezos Foundation was founded by Johann Gevers. Arthur studied applied mathematics, computer science, and physics in France and financial mathematics at New York University under Nassim Nicholas Taleb before working in quantitative finance.[4] Kathleen studied at Cornell University and worked at a hedge fund and as a consultant.[5] Arthur was the leader of an anarcho-capitalist group in New York, and Kathleen was a libertarian Republican who became interested in politics after listening to Rush Limbaugh at age 5; the two of them met at a crypto-anarchist lunch in 2010.[6] Arthur was a follower of Patri Friedman, the founder of The Seasteading Institute, and he learned of Gevers when Friedman hired him for a project to build a libertarian city in Honduras.[4]

While working at Morgan Stanley in 2014, Arthur Breitman released two papers proposing a new type of blockchain under the pseudonym "L. M Goodman", referencing a journalist at Newsweek who had misidentified the creator of Bitcoin.[4] He chose the name "Tezos" after writing a program to list unclaimed websites that could be pronounced in English.[4] In 2015, he registered Dynamic Ledger Solutions Inc (DLS) in Delaware with himself as chief executive.[4] The Breitmans contracted French firm OCamlPro to help develop the software.[4] Arthur worked at Morgan Stanley at the time, but he did not provide them with notice of his work on Tezos as required by the Financial Industry Regulatory Authority (FINRA),[6] and he was eventually fined $20,000.[7] He sought to raise $5 to $10 million from banks but was unable to find backers. By 2016, he left Morgan Stanley; Tezos received $612,000 from 10 backers while the Breitmans planned for an initial coin offering (ICO).[6]

In 2016, Arthur travelled to meet Gevers in Zug, Switzerland, to set up a Swiss foundation in order to avoid US securities laws and benefit from the lax banking regulations and effective corporate tax rate of zero.[4][8] In 2017, Gevers created the Tezos Foundation in Zug to support the project and raised $232 million in Bitcoin and Ethereum in one of the biggest initial coin offerings (ICOs) at the time.[4][9][10] At the time, he was also establishing Monetas, his own digital currency.[5] They planned for the foundation to become a non-profit that would raise money through the ICO and acquire DLS, which owned the group's technology.[4] They received a $1.5 million investment from Tim Draper and hired public relations firm Strange Brew to promote their project.[6] The firm was alleged to have falsely claimed that large American financial firms were using Tezos.[4][11] Subsequently, the Breitmans and the head of the foundation, Johann Gevers, publicly feuded over control of the project.[10][12][13] The disagreements led to delays in the deployment of Tezos, which caused investors to bring lawsuits alleging unauthorized sales of securities.[10] In 2020, the Tezos founders settled the lawsuits, with the Tezos Foundation paying $25 million.[14]

ICO and legal disputesEdit

The fundraiser for Tezos began on July 1, 2017, and received 66,000 bitcoins and 361,000 ethers, which had a market value of $232 million. The contributions were termed "non-refundable donations", which Kathleen Breitman likened to a pledge drive where people would receive tote bags, though some participants considered them to be an investment.[6] If considered an investment rather than a donation, it would fall under the purview of the Securities and Exchange Commission (SEC).[6][8] After the ICO, it was planned that the Tezos Foundation would pay to acquire DLS, and if the Tezos blockchain functioned for at least three months, the Breitmans would receive 8.5% of the ICO and 10% of the tokens.[5]

By October, the Breitmans and Gevers were in a dispute over control of the project, with the Breitmans alleging Gevers pressured the foundation council into signing a contract giving him a bonus of $1.5 million.[15][16][6] Gevers refused to give the Breitmans their payout, which was valued at around $70 million in cryptocurrency.[17] By December, three lawsuits had been filed in the United States alleging fraud during the fundraiser and that Tezos was an unregistered security.[18] In 2018, Gevers resigned and received $400,000, and the foundation board was replaced; Tezos went live that September.[4][3] The Tezos Foundation paid $25 million in 2020 to settle its lawsuits before federal courts ruled on whether the ICO was a sale of unregistered securities.[14] Arthur Breitman joined the foundation's council in 2021.[19]


The primary protocol of Tezos utilizes liquid proof of stake (LPoS) and supports Turing-complete smart contracts in a domain-specific language called Michelson. Michelson is a purely functional stack-based language with a reduced instruction set and no side effects, designed with formal verification in mind.[20][21][22][23]

In Tezos' LPoS model, network nodes that validate blocks and add them to the blockchain – known as bakers – are selected to perform those actions proportionally to their share of rolls of 8,000 XTZ that they put up for stake, and a baker receives staking rewards in the form of newly minted XTZ after successfully validating a block and adding it to the blockchain.[24] Holders of XTZ can delegate their XTZ to bakers to share in the staking rewards that bakers receive.[24] Holders of XTZ who do not stake or delegate their XTZ risk suffering a loss in value due to inflation as new XTZ are created and distributed to bakers for validating new blocks and adding them to the blockchain. As of January 2021, nearly 80% of all XTZ in circulation were either directly staked by bakers or delegated to bakers for staking.[25]

The Tezos protocol allows itself to be amended by a staged process performed by committing operations to the stored blockchain to submit proposals (intended code changes) and to vote on those changes. If a proposal receives enough votes the protocol updates itself to incorporate the code changes.[26]

The Tezos blockchain has been used for NFTs as an alternative to more energy-intensive projects such as Ethereum.[27]

Token standardsEdit

  1. FA1.2 (TZIP-7)
    • An ERC20-like fungible token standard for Tezos. At its core, FA1.2 contains a ledger which maps identities to token balances, providing a standard API for token transfer operations, as well as providing approval to external contracts (e.g. an auction) or accounts to transfer a user's tokens.[28]
  2. FA2 (TZIP-12)
    • A standard for a unified token contract interface, supporting a wide range of token types and implementations.[29]
    • Tokens might be fungible or non-fungible.[29]
    • A token contract can be designed to support a single token type (e.g. ERC-20 or ERC-721) or multiple token types (e.g. ERC-1155) to optimize batch transfers and atomic swaps of the tokens.[30]
  3. TZIP-16
    • A standard for accessing contract metadata in JSON format in on-chain storage or off-chain using IPFS or HTTP(S).[31]


In 2018, the Tezos Foundation commissioned the audit company Least Authority to perform five audits, which were published in March 2019.[32] These audits determined that Tezos protects against chain reorganizations and selfish-baking,[33] which are two common issues in blockchains using Nakamoto-style consensus.[34] A subsequent analysis confirms that selfish baking in Tezos results in insignificant profits, even when the baker attempting it has a very large portion of the stake.[citation needed] An independent 2020 study revealed a potential flaw in the current consensus proof of stake mechanism that Tezos uses, providing a theoretical analysis of the feasibility and profitability of a block stealing attack referred to as "selfish endorsing". A change to the protocol was proposed to reduce the profitability of this dishonest behavior.[35] With implementation of Tenderbake protocol amendment, the described behavior was mitigated and is no longer actual.[36]


  1. ^ Allombert, Victor; Borgouin, Mathias; Julian, Tesson (2019). "Introduction to the Tezos Blockchain". arXiv:1909.08458 [cs.DC].
  2. ^ "Tezos Protocols". TzStats. Archived from the original on 2021-01-08. Retrieved 2021-01-06.
  3. ^ a b Bart, Katharina (2018-11-21). "Tezos Seeks Revamp, Scars Remain". finews.com. Retrieved 2021-12-19.
  4. ^ a b c d e f g h i j k Lewis-Kraus, Gideon (June 19, 2018). "Inside the World's Biggest Crypto Scandal". Wired. Archived from the original on 18 October 2020. Retrieved 24 October 2020.
  5. ^ a b c Bart, Katharina (2017-08-03). "Record ICO's Swiss Ties Raise Eyebrows". finews.com. Retrieved 2021-12-19.
  6. ^ a b c d e f g Irrera, Anna; Stecklow, Steve; Neghaiwi, Brenna Hughes (2017-10-18). "Special Report: Backroom battle imperils $230 million cryptocurrency venture". Reuters. Retrieved 2021-12-14.
  7. ^ Irrera, Anna; Stecklow, Steve; McCrank, John (2018-04-20). "Wall Street regulator sanctions Tezos cryptocurrency project co-founder". Reuters. Retrieved 2021-12-17.
  8. ^ a b Rodrigues, Usha R. (2020). "Embrace the SEC". Washington University Journal of Law & Policy. 61: 133–154.(subscription required)
  9. ^ Cohney, Shaanan; Hoffman, David; Sklaroff, Jeremy; Wishnick, David (2019). "Coin-Operated Capitalism". Columbia Law Review. 119 (3): 661. ISSN 0010-1958. JSTOR 26652184.
  10. ^ a b c Vigna, Paul (February 1, 2018). "Bitcoin Brawl: A New Twist in Tezos's $232 Million Coin Offering". WSJ.com. Archived from the original on 29 October 2020. Retrieved 26 October 2020.
  11. ^ "Tezos Fights Over ICO Millions". finews.com. 2017-10-19. Retrieved 2021-12-19.
  12. ^ Cheng, Ari Levy,Evelyn (2017-11-30). "Investors are shunning new cryptocurrencies even as they pour money into bitcoin". CNBC. Retrieved 2021-08-24.
  13. ^ Wong, Joon Ian. "The $400 million raised to create a new cryptocurrency is now at risk". Quartz. Retrieved 2021-08-24.
  14. ^ a b Irrera, Anna; Stecklow, Steve (September 1, 2020). "Tezos Legal Settlement Gets Final OK, Ending Three-Year Court Battle". Reuters. Archived from the original on 29 October 2020. Retrieved 26 October 2020.
  15. ^ Bart, Katharina (2017-10-20). "Tezos Foundation Head Hits Back". finews.com. Retrieved 2021-12-19.
  16. ^ Roberts, Jeff John (2017-10-19). "Tezos in Trouble? Infighting After a Major ICO". Fortune. Retrieved 2021-12-19.
  17. ^ Hody, Peter (2017-12-05). "Tezos: Foundation Head May Hold Trump Card". finews.com. Retrieved 2021-12-19.
  18. ^ Stecklow, Steve; Irrera, Anna; Neghaiwi, Brenna Hughes (2017-12-01). "Exclusive: Tezos founders push for legal bailout from Swiss foundation". Reuters. Retrieved 2021-12-17.
  19. ^ "Tezos Co-Founder Joins Swiss Foundation". finews.com. 2021-02-24. Retrieved 2021-12-19.
  20. ^ Bernardo, Bruno; Cauderlier, Raphaël; Hu, Zhenlei; Pesin, Basile; Tesson, Julien (18 September 2019). "Mi-Cho-Coq, a framework for certifying Tezos Smart Contracts". arXiv:1909.08671 [cs.PL].
  21. ^ A. Das and S. Balzer and J. Hoffmann and F. Pfenning and I. Santurkar (2019). "Resource-Aware Session Types for Digital Contracts". 2021 2021 IEEE 34th Computer Security Foundations Symposium (CSF). pp. 1–16. arXiv:1902.06056. doi:10.1109/CSF51468.2021.00004. ISBN 978-1-7281-7607-9. ISSN 2374-8303. S2CID 53987556. Archived from the original on 2021-05-28. Retrieved 2020-12-31.
  22. ^ Harz, Dominik; Knottenbelt, William J. (2018). "Towards Safer Smart Contracts: A Survey of Languages and Verification Methods". p. 4. arXiv:1809.09805 [cs.CR].
  23. ^ Chen, Shiping (2018). Blockchain -- ICBC 2018 : first International Conference, held as part of the Services Conference Federation, SCF 2018, Seattle, WA, USA, June 25-30, 2018, Proceedings. Cham, Switzerland: Springer. pp. 78–80. ISBN 978-3-319-94478-4. OCLC 1042075107. Archived from the original on 2021-05-28. Retrieved 2021-03-06.
  24. ^ a b "Tezos (XTZ)". research.binance.com. 6 April 2020. Archived from the original on 2020-10-30. Retrieved 2020-10-24.
  25. ^ "Tezos Bakers". Archived from the original on 12 December 2020. Retrieved 6 January 2021.
  26. ^ Vigna, Paul (2018). The Truth Machine: The Blockchain and the Future of Everything (March 2019 ed.). Picador. p. 89. ISBN 978-1250304179.
  27. ^ Tabuchi, Hiroko (2021-04-13). "NFTs Are Shaking Up the Art World. Are They Also Fueling Climate Change?". The New York Times. Retrieved 2022-03-24.
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  29. ^ a b "TZIP-12: FA2 Multi-Asset Interface". tzip.tezosagora.org. Archived from the original on 2021-02-05. Retrieved 2021-01-02.
  30. ^ "Proposal TZIP-12". GitLab. Archived from the original on 2020-12-31. Retrieved 2021-01-02.
  31. ^ "Contract Metadata on Tezos". Tezos Agora Forum. 2020-10-01. Archived from the original on 2020-11-08. Retrieved 2020-11-01.
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  33. ^ "Analysis of Emmy+". Nomadic Labs. 2019. Archived from the original on 2020-06-19. Retrieved 2020-06-18.
  34. ^ Brown-Cohen, Jonah; Narayanan, Arvind; Psomas, Christos-Alexandros; Weinberg, S. Matthew (2018). "Formal Barriers to Longest-Chain Proof-of-Stake Protocols". arXiv:1809.06528 [cs.CR].
  35. ^ Neuder, Michael; Moroz, Daniel J.; Rao, Rithvik; Parkes, David C. (2020-04-07). "Selfish Behavior in the Tezos Proof-of-Stake Protocol". arXiv:1912.02954 [cs.CR].
  36. ^ Tenderbake Protocol Draft https://gitlab.com/tezos/tzip/-/blob/master/drafts/current/draft_tenderbake.md

External linksEdit