Antelope and EOSIO: the software behind EOS

6 min read

EOSIO in one paragraph

EOSIO was ambitious. It promised a platform where apps could serve millions of users without charging them per transaction. Many of its ideas survived. What did not survive was the relationship between Block.one and the EOS community. In 2021, Block.one stopped developing EOSIO, and the community had to decide who would maintain the code its chain depended on.

Why EOS forked from EOSIO

By 2021, a large part of the EOS community felt that Block.one had raised about $4.1 billion in its ICO and then moved on. The company launched the Bullish exchange, its co-founder and CTO Dan Larimer left at the end of 2020, and EOSIO development slowed and then stopped. The EOS Network Foundation (ENF) formed in August 2021 to fund the ecosystem independently.

Relying on code maintained by a company that was no longer engaged was a risk. So the ENF set up the EOSIO+ working group to take over the software. In March 2022, EOS and Telos formed a coalition, and WAX and UX Network joined a week later. Work began under the codename Mandel, a community fork of EOSIO 2.0 with selected parts from 2.1 and 2.2.

On August 17, 2022, the fork was renamed Antelope, with Leap as its node software. On September 21, 2022, EOS activated Leap 3.1 through a coordinated hard fork. Media at the time described it as the moment the network severed its technical ties to Block.one. The broader story of the split is in our EOS history and roadmap.

From Leap to Spring: a timeline

1. June 2018EOS mainnet launches on EOSIO

   Genesis block on June 8. Block.one maintains the software.

2. 2021Block.one stops EOSIO development

   The ENF forms and launches the EOSIO+ working group.

3. March 2022Antelope coalition forms

   EOS and Telos join first; WAX and UX Network follow a week later.

4. August 2022Mandel becomes Antelope

   The fork gets its name; the node software is called Leap.

5. September 2022Leap 3.1 activated on EOS

   Hard fork on September 21. EOS now runs Antelope.

6. April 2023Leap 4.0

   Multi-threading and performance improvements.

7. Early 2024Leap 5.0

   Adds the BLS cryptography groundwork needed for fast finality.

8. September 2024Spring 1.0 and Savanna

   Stable release early in the month; Savanna activated on EOS on September 25.

9. 2025Spring 1.1, 1.2 and 2.0 development

   Spring 1.2.0 published in June; Spring 2.0 development builds from July.

Antelope Leap and Spring: what changed for users

Leap: stability and performance

Leap 3.1 was mostly about continuity: keep the chain running with community-maintained code. Leap 4.0 in April 2023 focused on speed and reliability with multi-threading. Leap 5.0 in early 2024 introduced the BLS protocol feature, which looked like a niche cryptography update but laid the groundwork for the next big change.

Spring: one-second finality

Spring 1.0 brought Savanna, a new consensus algorithm. Before it, a transaction on EOS took about 3 minutes to become irreversible, even though blocks came every half second. Savanna turned the 21 block producers into finalizers that vote on every block using aggregated BLS signatures. When 15 of 21 agree, the block is final.

The Spring 1.0 release notes put the improvement as going from 3 minutes to 1 second under typical network conditions. For exchanges, bridges and anyone waiting on a deposit, that is the difference between waiting for a coffee and not noticing at all. Block time stayed at 0.5 seconds.

How producers are elected and what they do as finalizers is covered in our DPoS and block producers guide.

What Antelope inherited from EOSIO

Antelope kept the parts of EOSIO that made it distinctive:

• Named accounts of 12 characters with owner and active permissions and built-in multisig. See our EOS account guide.
• The resource model: CPU and NET rented via PowerUp, RAM bought and sold on an on-chain market. Explained in EOS RAM, CPU and NET.
• Smart contracts as accounts, with contract code and table data stored in RAM that someone owns.
• Delegated Proof of Stake with 21 active producers and 15-of-21 governance.

On top of that, the community has added features through system contract upgrades: REX 2.0 staking, the 2.1 billion supply cap, RAM transfers and gifting, and the core.vaulta wrapper that lets every system action be paid in the A token.

The EOS EVM chapter

One notable Antelope-era experiment was EOS EVM, an Ethereum-compatible environment running as a smart contract on the native chain. Its mainnet beta launched in April 2023 and supported familiar tools like MetaMask, Hardhat and ethers.js. After the Vaulta rebrand it was called Vaulta EVM, but support ended in October 2025 and users were pointed to the exSat XSAT EVM instead. Today it is history, not something to build on.

Antelope chains today

Because these chains share the same software, wallets like Anchor and Wombat can support several of them with one app. Our EOS wallet guide covers which ones still keep up with Vaulta.

For developers: where things live now

• Node software: Spring, on GitHub under AntelopeIO.
• Documentation: docs.vaulta.com (the old docs.eosnetwork.com paths moved there).
• Wallet connection SDK: WharfKit, the successor to Anchor Link and UAL.
• Testnet: Jungle4.
• Token contracts: core.vaulta for A, eosio.token for legacy EOS. Query both when showing balances.

To inspect accounts, contracts and transactions, use an explorer such as Unicove or EOS Authority. Our EOS block explorer guide lists working options.

Why it matters for EOS holders

The move from EOSIO to Antelope is the reason EOS still exists as an independent network. Without the fork, the chain would have depended on unmaintained code from a company that had stepped away. With it, the community gained control of upgrades and shipped real improvements like one-second finality. Whether that translates into adoption and value is a separate question, which we look at honestly in "Is EOS safe?" and EOS vs Ethereum and Bitcoin.

Frequently asked questions

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