LitVM Architecture: How the Hybrid Rollup Works
A technical breakdown of LitVM's execution engine, SP1 zero-knowledge proving system, shared sequencing, bridging, and multi-layer security model.
Updated
LitVM works as Litecoin's first trustless EVM rollup by operating as a hybrid rollup rather than a pure zkRollup. Arbitrum Nitro executes transactions optimistically to provide immediate confirmations, while the Succinct SP1 zkVM generates zero-knowledge validity proofs over the state transitions to provide settlement finality in minutes instead of a seven-day dispute window. LitVM is currently live on its LiteForge testnet while mainnet has not launched, and the $LITVM governance token does not exist as a tradeable asset.
The Hybrid Architecture: Nitro Execution and SP1 Proving
LitVM separates execution from validity proving to optimize throughput and development velocity:
- Execution Layer (Arbitrum Nitro): LitVM runs as an Arbitrum Orbit chain using the Nitro stack, targeting EVM equivalent execution (Shanghai version). It processes transactions optimistically, batching up to 10,000 transactions per rollup block with parallel processing and calldata compression.
- Proving Layer (Succinct SP1 zkVM): Instead of waiting for a multi-day fraud challenge window, LitVM compiles its Nitro state transition function directly into Succinct's general-purpose SP1 RISC-V zkVM. SP1 produces zero-knowledge validity proofs over the Rust execution.
Why SP1 Avoids Traditional zkEVM Bottlenecks
Building a traditional zkEVM requires writing complex arithmetic circuits that mirror every EVM opcode. This approach requires multi-year engineering efforts and complete circuit rewrites whenever Ethereum implements an EVM upgrade.
Because the Arbitrum Nitro state transition function is written in Rust, Succinct SP1 can prove it as an arbitrary Rust program without customized circuit design. SP1 delivers proving costs of roughly $0.01 to $0.02 per transaction. Using recursive proof aggregation, the marginal proving cost remains flat as transaction volume scales.
The Core Modular Stack
LitVM coordinates specialized modular components across the transaction lifecycle:
- Execution: Arbitrum Nitro provides EVM execution, sub-second block times, and compatibility with standard Ethereum toolchains.
- Proving: Succinct SP1 zkVM generates cryptographic validity proofs for execution batches.
- Sequencing: Espresso operates as a permissionless shared sequencer to order transactions, preventing single-operator halts and mitigating censorship risk.
- Operations Infrastructure: Caldera operates rollup-as-a-service infrastructure, providing the RPC endpoints, WebSocket connections, block explorer, faucet, and system monitoring.
- LTC Bridging: BitcoinOS Grail provides trustless bridging between the Litecoin mainchain and the rollup.
- EVM Bridging: Arbitrum Bridge transfers ETH, USDC, USDT, and standard ERC-20 tokens.
Dual Bridging Model: Grail vs. Arbitrum Bridge
LitVM relies on two distinct bridging paths depending on the native asset:
| Feature | BitcoinOS Grail Bridge | Arbitrum Bridge |
|---|---|---|
| Assets Handled | Native Litecoin (LTC to zkLTC) | ETH, USDC, USDT, ERC-20s |
| Mechanism | BitSNARK verification, 300-byte proofs | Arbitrum native bridge contracts |
| On-Chain Footprint | Taproot locks on Litecoin L1 | EVM settlement contracts |
| Trust Assumptions | 1-of-n honest verifier, non-custodial (no multisig) | Optimistic execution plus zero-knowledge proofs |
| Minted Asset | zkLTC (backed 1:1, elastic supply) | Bridged ERC-20 representations |
When LTC moves across the Grail bridge, zkLTC is minted 1:1 to serve as the rollup's base currency and gas token. Because zkLTC tracks locked LTC on the Litecoin mainchain, users pay network gas in an asset the rollup itself does not issue.
Three Settlement Phases
LitVM's roadmap distributes settlement across three distinct phases to ensure long-term base-layer independence:
- Phase 1 (Settlement on Ethereum): LitVM settles validity proofs and data availability to Ethereum. Both bridges operate, Espresso sequences transactions, and zkLTC pays for gas.
- Phase 2 (Dual Anchoring): Finalized transaction batches are additionally anchored to the Litecoin mainchain. Proofs are inscribed using standard extended transactions without requiring any hard forks or protocol alterations to Litecoin.
- Phase 3 (Canonical Litecoin Settlement): Settlement migrates entirely off Ethereum. Litecoin becomes the sole canonical finality layer, securing LitVM directly through Litecoin's Scrypt proof-of-work network.
Performance Comparison
The following table outlines the operational metrics across LitVM and base layers:
| Layer | Throughput | Transaction Fees | Finality Time |
|---|---|---|---|
| LitVM (LiteForge) | Thousands of TPS | Sub-cent (< $0.01) | Minutes (via ZK validity proof) |
| Litecoin L1 | ~56 TPS | Sub-cent | ~2.5 minutes (block confirmation) |
| Ethereum L1 | ~15 TPS | $1.00–$100.00+ | 12+ minutes |
The Six Security Layers
LitVM enforces safety across the entire rollup lifecycle through six interdependent security mechanisms:
- Litecoin Mainchain: Provides the root of security, anchored by 14 years of uninterrupted Scrypt proof-of-work running at over 2 PH/s.
- Ethereum Settlement: Provides early-phase consensus verification and finality guarantees.
- SP1 Validity Proofs: Cryptographically prevents invalid state transitions or unauthorized balance updates from settling.
- Espresso Shared Sequencing: Eliminates centralized sequencer points of failure, protecting against censorship and single-operator outages.
- BitcoinOS Grail Bridge: Enforces a 1-of-n honest verifier model backed by BitSNARKs, avoiding custodial multisig risk.
- Arbitrum Bridge: Protects inbound ERC-20 assets using dual optimistic and zero-knowledge verification rules.
Supplementary safeguards include third-party audits, active bug bounties, forced transaction inclusion via the settlement layer, and emergency withdrawal pathways.
Network State and Testnet Status
As of 15 August 2026, the LitVM LiteForge testnet (Chain ID 4441) has processed 237.1 million transactions across 40.5 million blocks with an average block time of 161ms, serving 13.1 million unique wallet addresses since launching in April 2026.
Users should note that $LITVM does not exist as a tradeable asset today. The Token Generation Event (TGE) will occur following testnet completion, and mainnet will launch only after audits and the TGE conclude.
Questions
How does LitVM work as a hybrid rollup?
LitVM pairs Arbitrum Nitro's execution engine with Succinct's SP1 zkVM. Transactions execute optimistically for rapid block production, while zero-knowledge validity proofs are generated over the execution to achieve finality in minutes, avoiding the multi-day dispute windows of standard optimistic rollups.
Why does LitVM use SP1 instead of building a zkEVM?
A traditional zkEVM requires writing complex arithmetic circuits for every EVM opcode, which takes years and requires updates with every EVM hard fork. Because the Arbitrum Nitro state transition function is written in Rust, Succinct SP1 proves it directly as a standard Rust program at roughly $0.01 to $0.02 per transaction.
How does LitVM bridge assets from Litecoin and Ethereum?
LitVM uses BitcoinOS Grail to bridge LTC trustlessly via BitSNARK proofs and 1-of-n verification to mint zkLTC 1:1 without multisigs. Separately, the Arbitrum Bridge brings in ETH, USDC, USDT, and ERC-20 tokens using standard EVM bridge contracts.
Is the LITVM token available to trade?
No, the $LITVM token does not exist as a tradeable asset. Mainnet has not launched, and the token generation event will occur only after testnet completion and security audits; any token trading under the LITVM name today is fraudulent.