Cardano

Charles Hoskinson and Jeremy Wood began Cardano in 2015. Hoskinson’s design essay said there was no single authoritative white paper; the project instead gathered research on consensus, programming languages, accounting and governance. Input Output coordinated engineering, the Cardano Foundation took standards and promotion, and EMURGO pursued commercial use.

Before mainnet, vouchers were sold mainly in Asia from October 2015 to January 2017. The sale allocated 25,927,070,538 ADA to buyers. Genesis added 5,185,414,108 ADA to the three organizations—2,463,071,701 to IOHK, 2,074,165,644 to EMURGO and 648,176,761 to the Foundation—making 31,112,484,646 available at launch. Those figures describe allocation, not identical authority over the future chain.

Byron mainnet started on September 29, 2017 with Ouroboros Classic, Daedalus and a federated topology. Founding entities maintained the trusted core and relay infrastructure. Proof of stake was present, but open stake-pool block production was not; calling Byron fully community operated would project Shelley backward.

Input Output chose a two-step escape. On February 20, 2020 the chain moved from Ouroboros Classic to a BFT bridge. A new Haskell node could understand the old Byron rules and prepare the next set. On July 29, the hard fork combinator switched to Shelley and Ouroboros Praos without erasing old transactions. Delegation and reward-sharing pools turned ADA ownership into selectable consensus weight.

Cardano did not deliver programmability in one switch. Allegra introduced token locking in December 2020. Mary made multiple assets first-class ledger values on March 1, 2021, allowing an issuer to define a minting policy without deploying an account-style token contract.

Alonzo arrived on September 12, 2021. Plutus scripts attached programmable conditions to extended UTXOs: a transaction had to provide the datum, redeemer and context that a validator accepted. This opened applications, but the original model made repeated data and scripts costly to carry. Vasil, activated September 22, 2022, added reference inputs, inline datums, reusable reference scripts and collateral outputs. The later upgrade responded to how developers actually had to compose transactions after Alonzo.

Chang activated on September 1, 2024 and moved the ledger into Conway. ADA holders could register as DReps or delegate governance power, but the bootstrap period deliberately limited what those representatives could decide. An interim constitutional committee and SPOs handled parameter and hard-fork votes while the community drafted a constitution and assembled representation.

Plomin on January 29, 2025 completed the second stage. DReps gained their full voting role, the complete CIP-1694 action set became available, and treasury withdrawals could pass through on-chain governance. Different actions require different combinations and thresholds among DReps, SPOs and the constitutional committee. ‘The community governs’ therefore describes a rule system, not a universal majority poll.

ADA has a 45-billion ceiling, but the ceiling is not circulating supply. At epoch 641, beginning July 3, 2026, 36,453,321,540 ADA circulated, 1,469,970,597 sat in treasury and 802,473,368 remained as unclaimed rewards. Deposits and fees brought total supply to 38,733,443,164; subtracting that total from the 45-billion maximum left 6,266,556,836 ADA in reserves.

Each epoch draws a parameterized fraction from that declining reserve and combines it with transaction fees. A portion funds the treasury and the remainder supplies staking rewards. Plomin made withdrawals a governance action, so monetary expansion now connects two constituencies: pools and delegators securing the chain, and voters deciding which public work receives treasury ADA.

The three pioneer entities relinquished the genesis keys, but a constitutional design needed a live test. On July 18, 2026, van Rossem moved mainnet to protocol version 11 at epoch 644. It added Plutus and cryptographic improvements while staying in Conway.

Its larger significance was procedural. DReps, SPOs and the constitutional committee proposed, debated and ratified the fork through the post-Plomin system; the official account called it the first Cardano upgrade completed entirely through on-chain governance. Input Output can still write code, the Foundation can vote and protect marks, and EMURGO can build markets. None of those roles now substitutes for the ratification path the ledger enforces.