Layer 2 blockchain · settles to Base
Horizen ticker ZEN
Summary
OP Stack rollup on Base, launched 9 December 2025 on Caldera's rollup-as-a-service platform. A sequencer node orders and executes transactions and posts batches to Base; full nodes rebuild Horizen's state from that data. Horizen's architecture docs say state proposals are assumed correct unless challenged within a dispute window (7 days in the standard configuration); initial proposals can be rejected by a threshold of a trusted multisig, and anyone can also submit an onchain fault proof. Block production uses no stake or work of its own. Until July 2025 Horizen was a separate proof-of-work UTXO chain forked from Zcash; a hard fork at block 1,807,300 blocked all transactions except miner rewards, and ZEN balances became claimable as an ERC-20 on Base. 3451620212223
Design
- System
- Layer 2 blockchainHorizen Mainnet (chain ID 26514) is an OP Stack rollup settling to Base, which settles to Ethereum, so Horizen calls it a Layer 3; it launched 9 December 2025. ETH pays gas; ZEN is an ERC-20 governance token on Base. The package listed Horizen as a UTXO Layer 1: that was the former proof-of-work chain (a 2017 Zcash fork), whose user transactions a hard fork stopped at block 1,807,300 on 23 July 2025 when ZEN moved to Base. Filed as a rollup because there is no separate Layer 3 class.
- Settles to
- BaseHorizen posts batches and state proposals to Base, and Base settles to Ethereum, so Horizen inherits both chains' assumptions plus its own. Deposits from Base arrive within minutes; withdrawals to Base take at least 7 days and a second claim transaction. Base documents about 20 minutes for its own batches to reach Ethereum finality, so Horizen blocks cannot be final sooner than the Base blocks that carry them.
- Settlement family
- Ethereum / EVM
- Scarce resource
- Other
- State model
- Accounts
- Finality
- Other
- Who makes blocks
- One sequencer. Horizen's docs describe a dedicated sequencer node, and the public RPC endpoint is hosted on Caldera infrastructure, but the reviewed pages do not name who holds the sequencer, proposer or contract-upgrade keys. Miners of the old proof-of-work chain no longer include user transactions.
- Fork choice
- No open fork choice on Horizen itself: the canonical chain is derived from batch data posted to Base, so Base's ordering, and through Base, Ethereum's finality, govern it. Horizen's docs say a trusted multisig can reject initial state proposals and that disputes are otherwise settled by interactive onchain fault-proof games open to anyone; this review did not confirm the live contract settings, the multisig members or who may propose.
Qualifications
- Scarce resource · Not applicable. Horizen block production uses no stake or work of its own. ZEN staking, reopened in July 2026, is a DAO-funded rewards program, not block production or validation.
- Finality · Partial. Horizen's docs do not publish finality stages. By design a transaction first rests on the sequencer, then on its batch being posted to Base, then on that Base data reaching Ethereum finality; withdrawals wait a 7-day dispute window.
- Data availability · Contested. Horizen's pages disagree in wording: the Layer 3 page and the Caldera announcement say data goes to Base, while the general architecture page says batches go to Base as calldata or, if configured, as blobs, and in another section that batches are recorded in Ethereum blobs. The reading most consistent with a Layer 3 is that Horizen posts to Base and Base posts to Ethereum; this is an inference, not a Horizen statement.
- Proof system · Unknown. Horizen's architecture docs describe two dispute paths within a window of 7 days in the standard configuration: a trusted multisig that can reject initial proposals, and fault proofs anyone can submit. The live contract configuration on Base, the multisig's members and whether the open path is enabled were not checked, and no independent risk review of Horizen was found.
- Chain level privacy · Partial. There is no protocol-wide shielding. Privacy is chosen per application (zero-knowledge tools, trusted hardware or none), and Vela was at version 0.2.0 on testnets. The old chain had already disabled its Zcash-derived shielded pool in February 2024.
- Pre migration history · Partial. Blocks before July 2025 belong to a different proof-of-work UTXO chain and its EVM sidechain EON, with different security. Their history was not carried into Horizen Mainnet; balances were loaded into claim vaults on Base by an authorized admin.
Tradeoffs
- Emphasizes
- Scalability
- Gives up
- Independent security and decentralized block production: one sequencer orders every transaction, safety rests on Base and then Ethereum plus Horizen's own proof and upgrade arrangements, a trusted multisig can reject state proposals, and neither its members nor the upgrade-key holders were found in Horizen's docs. Withdrawals back to Base wait at least 7 days. Leaving its own proof-of-work chain also ended open mining participation.Security is inherited through two layers rather than emphasized independently. Horizen's privacy tools are opt-in per application; its Vela confidential-compute service relies on trusting AWS Nitro Enclave hardware and was on test networks only at review time.
- Full node at home
- Unknown 428Horizen publishes no node-operator guide or hardware figures. Its architecture page says full nodes read batch data from Base and re-derive the chain, so a verifying node also needs Base data; Base's own docs call running a Base node resource-expensive and require an Ethereum RPC and beacon endpoint.
- Throughput claims
- No classified figure recorded
Scaling layers
No scaling layer recorded in this profile.
Capabilities
| Capability | How it is provided | Notes and sources |
|---|---|---|
| Account abstraction | Structured assessment pending | Not yet assessed for any chain. |
| Atomic swaps | Unknown | No protocol-level trust-minimized swap on Horizen was reviewed; EVM contracts could implement one, but none was verified. |
| Authenticated data publication | Unknown | Not yet assessed under this row's current definition. |
| Light clients | Unknown | No light-client verification path for Horizen Mainnet was found in the reviewed docs. |
| Native staking or delegation | Structured assessment pending | Not yet assessed for any chain. |
| On-chain governance | Structured assessment pending | Not yet assessed for any chain. |
| Parallel execution | Structured assessment pending | Not yet assessed for any chain. |
| Payment or state channels | Unknown | No payment or state channel layer anchored to Horizen was found. Tachyon markets its beta private bridge as settlement channels, but Horizen's announcement describes a solver network and trusted hardware routing transfers between Base and Horizen, not channels that open, update and settle or dispute on Horizen. 2526 |
| Programmable spending | Native (protocol or core-team software) Earlier definition | Horizen is EVM-compatible and runs ordinary Solidity contracts, so spend conditions are smart contracts; the retired proof-of-work chain used transaction scripts instead. 23 |
| Protocol-verified messaging | Structured assessment pending | Not yet assessed for any chain. |
| Reversible transfers or recovery | Unknown | Not yet assessed under the current definitions; no protocol feature for reclaiming, cancelling or delaying a payment, or for regaining control without a lost key, was found on Horizen. Horizen lists a Safe multisig deployment through Den; a plain multisig threshold does not meet part (b), and its delay or recovery options were not reviewed. 15 |
| Rollups | Unknown | No chain anchored to Horizen was found. Horizen is itself a rollup on Base; see the mechanism and settlement sections of this profile. |
| Shielded transfers | Structured assessment pending | Not yet assessed for any chain. |
| Signed partial offers | Unknown | Not yet assessed under this row's current definition. |
Reading these values
- How this feature is provided
- Built into the protocol, core-team software or independent software says where a feature lives and who can change it. These are implementation layers, not quality: core-team software is not closer to the protocol than independent software.
- Structured assessment pending
- The shared review has not assessed this feature for any chain yet (Account abstraction, Native staking or delegation, On-chain governance, Parallel execution, Protocol-verified messaging and Shielded transfers). That does not mean it is absent, and a chain’s profile may already describe it.
- Unknown
- The review has not established this for this chain under the current definition; the note beside it says why. Unknown is not absent and not a low score. A feature reads “Not present” only when a source shows it is absent.
- Earlier definition
- Payment or state channels, Programmable spending and Rollups keep the earlier definition until the next fact-check. There, “Native” does not separate the protocol from core-team software, “Ecosystem software” does not say who publishes it, and “Partial” does not say which layer.
- Reading across rows
- The list of capabilities is incomplete. Do not read these rows as a chain leading or lagging overall.
Ecosystem & custody
| Product type | Status | Notes and sources |
|---|---|---|
| Automated market makers | Unknown | The earlier review did not verify absence on Horizen, so the rule that absence needs a source makes this unknown rather than not present. Horizen's own ecosystem directory lists no live exchange on Horizen Mainnet; its planned private exchange, ZENDEX, is marked coming soon and its site asks users to register interest. ZEN's AMM liquidity sits on Base (Aerodrome and Uniswap v3 pools named at the July 2025 migration), which is a different chain. 192427 |
| Issuer-native stablecoins | None found | No issuer-native stablecoin was found on Horizen. USDC.e on Horizen is bridged through Stargate against USDC locked on Base; Horizen's docs say it is not issued by Circle, not directly redeemable with Circle and has no CCTP access. 8 |
| Algorithmic stablecoins | Unknown | The earlier review did not verify absence, so the rule that absence needs a source makes this unknown rather than not present. No algorithmic stablecoin with material usage on Horizen was identified, and Horizen's ecosystem directory lists none. 19 |
| Bridges | Native to the protocolHorizen native bridge (ETH, Base to Horizen), Stargate on LayerZero (ZEN, USDC.e, cbBTC), Tachyon (beta private bridge) | The OP Stack bridge moves ETH between Base and Horizen: deposits take minutes, withdrawals at least 7 days plus a claim step. Stargate, built on LayerZero, carries ZEN, USDC.e and cbBTC; Horizen's docs say most transfers finish in under 2 minutes for a 0.06% fee. Tachyon's beta, live since May 2026, routes private transfers between Base and Horizen. Risk: The native bridge depends on Base and on Horizen's proof system; Horizen's docs say a trusted multisig can reject state proposals, but its members, the live contract configuration and the upgrade-key holders were not found in Horizen's docs, and no independent risk review was found. Stargate assets depend on LayerZero messaging and lock contracts on Base; USDC.e is not Circle-issued and cbBTC is backed by Coinbase custody. Tachyon relies on solvers and trusted hardware and is beta software. 48910112526 |
| Block explorers | First-partyHorizen Explorer (explorer.horizen.io) | Horizen's docs list one mainnet explorer, powered by Caldera, with a separate testnet instance. No independent explorer was found. Explorer indexes are provider data, not consensus. 1213 |
| Hardware wallets | ThinLedger (through MetaMask or Rabby), Trezor (through MetaMask or Rabby) | See custody rows: Horizen's docs route Ledger through MetaMask or Rabby, and Trezor lists the Horizen network but Trezor Suite does not include it, so Trezor use also goes through those wallets. 15303334 |
Hardware-wallet custody
| Device maker | Status | What users can and cannot do |
|---|---|---|
| Ledger | Through an intermediaryMetaMask or Rabby (third-party wallet apps)Same as native: Unknown | Can: Sign Horizen Mainnet transactions with a Ledger using MetaMask or Rabby as the interface, per Horizen's wallet docs Can: Claim migrated ZEN from the old chain by signing a message with the Horizen device app (v2.4.1 or later) and Horizen's Ledger signing tool, per Horizen's migration docs Cannot: Manage Horizen Mainnet in Ledger Wallet itself: Ledger Wallet's network list has no Horizen Mainnet entry, and Ledger's Horizen page names ZEN but no networkHorizen's supported-wallets page documents Ledger use on Horizen Mainnet with MetaMask or Rabby as the interface. Ledger's page 'Horizen Wallet - Buy, manage & hold your ZEN' is a general product page; it does not say whether it covers the retired proof-of-work chain, the ERC-20 on Base or Horizen Mainnet. 15183032 |
| Trezor | Through an intermediaryMetaMask or Rabby (third-party wallet apps named by Trezor)Same as native: Unknown | Can: Use ETH and ZEN on the Horizen network with a Trezor Safe 3, Safe 5 or Safe 7 through MetaMask or Rabby; Trezor's Horizen page lists Base and Horizen as supported networks, and its Ethereum page lists Horizen Can: Hold ZEN on Base in Trezor Suite, which supports the Base network Cannot: Manage Horizen network accounts in Trezor Suite itself: Suite's current network list does not include HorizenTrezor's Horizen page names Trezor Suite, MetaMask and Rabby without tying them to networks. Because Trezor Suite's network code has Base but no Horizen entry, Suite can hold ZEN on Base while the Horizen network itself goes through a third-party wallet. Older models were not reviewed. 333435 |
Public data
iKnow Blockchain has no public-data lookups for Horizen yet. This is a limit of the service, not a statement about the network.
| Lookup | Status | What it covers and its limits |
|---|---|---|
| Address or account | Not available yet | Public-data lookups for this chain are not built yet. |
| Tokens and assets | Not available yet | Public-data lookups for this chain are not built yet. |
| NFTs | Not available yet | Public-data lookups for this chain are not built yet. |
| Transactions | Not available yet | Public-data lookups for this chain are not built yet. |
Sourced developments
Developments: Review overdue Reviewed Sep 27, 2026; next review was due Oct 7, 2026, 12:00 UTC.
Publication date · newest first
-
Repository for the retired proof-of-work client archived
The HorizenOfficial/zen repository, home of the client for Horizen's former proof-of-work chain, was archived and made read-only; its notice says vulnerability reports are no longer accepted and points to the current Horizen docs.
- Implementation:repository archived
- Release:final release was zend 6.0.0 (1 July 2025)
- Activation:archived 4 August 2026
Sources: Horizen contributors — HorizenOfficial/zen (archived) (external site) · Horizen contributors — zend v6.0.0 release notes (external site)
-
ZEN staking opened on Horizen Mainnet
Following the DAO's approval of ZenIP 42408 in March 2026, Horizen opened ZEN staking on Horizen Mainnet, with reward distribution set to begin on 27 July 2026. Stakers bridge ZEN from Base via Stargate and need ETH for gas.
- Proposal:approved as ZenIP 42408
- Implementation:staking app live
- Release:Released
- Activation:rewards scheduled from 27 July 2026
Sources: Horizen Blog — How to Stake ZEN on Horizen Mainnet (external site) · Horizen Blog — $ZEN Staking is Back on Horizen (external site)
-
Horizen Labs opened Vela confidential compute to developers
Horizen Labs named its confidential-compute environment Vela and released it as a local development kit, with dedicated testnet instances on request. Vela's docs now describe version 0.2.0 on Base Sepolia and Horizen testnet, and its roadmap names Base mainnet as the next milestone.
- Implementation:version 0.2.0 released
- Release:local development and testnets
- Activation:not on mainnet as of this review
Sources: Horizen Blog — Introducing Vela: The Confidential Compute Layer on Horizen (external site) · Horizen Documentation — Vela introduction (external site) · Horizen Documentation — Vela roadmap (external site)
-
Horizen Mainnet launched as a Layer 3 on Base
Horizen launched its OP Stack mainnet settling to Base, run on Caldera's rollup service, completing its move from a standalone proof-of-work chain. ZEN had already migrated to Base as an ERC-20 in July 2025.
- Implementation:mainnet deployed
- Release:Released
- Activation:live since 9 December 2025
Sources: Horizen Blog — Welcome to Privacy on Base (external site) · Horizen Blog — Horizen Partners with Caldera to Launch Privacy-first Blockchain on Base (external site) · Horizen Blog — Horizen 2025 Year in Review (external site)
Topics your AI can explain
Your AI can explain these topics for Horizen through the connection, with sources.
Known gaps
What this profile's review did not establish:
- Who operates the sequencer and holds the proposer and contract-upgrade keys was not confirmed; Horizen names Caldera only as its rollup infrastructure provider.
- Whether fault proofs are live and open to anyone on Horizen's Base contracts, and who sits on the trusted multisig that can reject proposals, was not checked onchain; Horizen's contract-address page does not list its rollup contracts on Base, and no independent risk review (for example an L2BEAT page) of Horizen was found.
- Horizen's pages describe data availability inconsistently (Base versus Ethereum blobs).
- Block time, finality stages, and any forced-inclusion or escape path if the sequencer censors or halts are not documented in the reviewed Horizen pages.
- No node-operator guide or hardware requirements for Horizen Mainnet were found, so home-node practicality is unknown.
- Ledger's Horizen page does not name a network, and Ledger Wallet's network list has no Horizen Mainnet entry; whether Ledger Wallet shows ZEN on Base natively was not verified.
- Trezor's Horizen and Ethereum pages list the Horizen network but do not tie wallet apps to networks; the Trezor rating rests on Trezor Suite's current network code, which has no Horizen entry.
- No live exchange on Horizen Mainnet was found; ZENDEX was listed as coming soon. Liquidity was not measured anywhere.
- Atomic swaps, light clients, channels, reversible transfers or recovery and chains anchored to Horizen were not reviewed.
- Whether anyone still runs the retired proof-of-work chain, and whether a public explorer for its history remains, was not checked.
Sources
Oldest dated source check: Source checked Sep 27, 2026 Next check due Oct 27, 2026.
- Horizen (external site)
- What is Horizen (external site)
- L3 Architecture (external site)
- Architecture (external site)
- Mainnet network details (external site)
- Gas on Horizen (external site)
- ZEN token (external site)
- USDC on Horizen (external site)
- cbBTC on Horizen (external site)
- How bridging works (external site)
- Bridge assets with Stargate (external site)
- Block explorer (external site)
- Horizen Explorer (external site)
- Contract addresses (external site)
- Supported wallets (external site)
- Migration overview (external site)
- Migration starting points (external site)
- Ledger wallet users (ZEN claim) (external site)
- Horizen ecosystem (external site)
- HorizenOfficial/zen (archived) (external site)
- zend v6.0.0 release notes (external site)
- Welcome to Privacy on Base (external site)
- Horizen Partners with Caldera to Launch Privacy-first Blockchain on Base (external site)
- Horizen Based: ZEN is Now Live on Base (external site)
- Bringing Private Cross-Chain Execution to Horizen with Tachyon (external site)
- Tachyon (external site)
- ZENDEX (external site)
- Run a Base Node (external site)
- Transaction Finality (external site)
- Horizen Wallet - Buy, manage & hold your ZEN (external site)
- Supported coins and assets (external site)
- ledger-live: coin-module loaders (list of networks Ledger Wallet can add) (external site)
- trezor-suite: Ethereum-style network configuration (develop branch) (external site)
- Safe & secure Horizen wallet (external site)
- Ethereum wallet (external site)
Report an error
Found something wrong or out of date? Reporting is free, and every chain goes through the same process. Published corrections appear in the public log.
Funding disclosure
Funding disclosures appear here when an upkeep arrangement exists, in the form “Upkeep funded by [name]; verdicts unaffected.” The funder ledger has not been published yet. Neutrality & funding