StarkEx is a permissioned validity rollup (or ZK-rollup) scaling engine developed by StarkWare. It leverages cryptographic STARK proofs (Scalable Transparent Argument of Knowledge) to generate a single proof that validates the correctness of a large batch of transactions executed off-chain. This proof is then submitted to the Ethereum mainnet, where it is verified by a smart contract, ensuring the integrity of the off-chain state transitions without re-executing every transaction. This architecture dramatically reduces the gas fees and latency for users while inheriting Ethereum's security guarantees.
LABS
Glossary
StarkEx
StarkEx is a permissioned Software-as-a-Service (SaaS) scaling engine that uses STARK validity proofs to power application-specific validiums or ZK-rollups, providing high throughput and flexible data availability.
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definition
VALIDITY ROLLUP
What is StarkEx?
StarkEx is a Layer 2 scaling engine that uses STARK proofs to batch and verify transactions off-chain before settling them on Ethereum, enabling high-throughput, low-cost applications.
The system operates with a centralized sequencer that orders transactions and generates the STARK proofs, which is why it is considered a permissioned or application-specific rollup. It is designed as an engine or SDK that projects can integrate to build high-performance applications like decentralized exchanges (DEXs) and NFT marketplaces. Notable implementations include dYdX (for perpetuals trading), Immutable X (for NFT minting and trading), and Sorare (for fantasy sports). Each application runs its own dedicated StarkEx instance, optimizing performance for its specific use case.
Key technical components include the Prover, which generates the computational integrity proofs, and the Verifier, a smart contract on Ethereum that checks these proofs. StarkEx supports several data availability modes: Rollup mode, where transaction data is posted on-chain (ensuring full Ethereum-level security), and Validium mode, where data is kept off-chain by a committee (enabling even higher throughput and lower costs but with different trust assumptions). This flexibility allows developers to choose the optimal trade-off between cost, throughput, and security for their application.
Compared to Optimistic Rollups, which have a long challenge period for fraud proofs, StarkEx's validity proofs provide instant finality for state transitions upon proof verification, typically within hours. Its development has been instrumental in proving the viability of ZK-rollup technology at scale, handling millions of transactions and significantly reducing the load on the Ethereum base layer. The underlying STARK proof system is quantum-resistant and does not require a trusted setup, contributing to its robust security model.
The evolution of StarkEx technology contributed directly to the development of Starknet, StarkWare's permissionless, general-purpose ZK-rollup network. While StarkEx is tailored for specific, high-performance applications, Starknet allows for composable, decentralized smart contracts. Together, they represent a key part of the Layer 2 scaling ecosystem, using advanced cryptography to scale blockchain capacity while maintaining the foundational security of Ethereum.
how-it-works
VALIDITY ROLLUP ARCHITECTURE
How StarkEx Works
StarkEx is a permissioned, application-specific validity rollup (ZK-rollup) engine that uses STARK proofs to batch and compress transactions off-chain before settling them on a base layer like Ethereum.
The core mechanism of StarkEx is the STARK proof, a cryptographic proof system that allows a prover (the StarkEx sequencer) to generate a proof attesting to the computational integrity of a batch of transactions. This proof, which is small and fast to verify, is submitted to an on-chain verifier contract on Ethereum. The verifier confirms the proof's validity without re-executing the transactions, ensuring the state transition is correct. This process bundles hundreds to thousands of transactions into a single proof, drastically reducing the data and computational load on the base chain.
A StarkEx-powered application operates with a designated operator (or sequencer) responsible for batching user transactions, generating the STARK proof, and managing the rollup state. Users interact with the application by signing off-chain messages, which the operator collects. The system's state—such as token balances in an exchange or ownership of NFTs—is maintained in a Merkle tree off-chain. Only the essential state data required for user withdrawals (the Merkle root) and the validity proof are posted to Ethereum, ensuring data availability and finality while keeping costs minimal.
StarkEx supports multiple data availability modes, which govern where transaction data is published. In Validium mode, data is kept off-chain with a Data Availability Committee (DAC), maximizing throughput and minimizing fees. In Volition mode, users can choose per-transaction whether their data goes on-chain (ZK-rollup mode) or off-chain (Validium mode). This flexibility allows developers to tailor the trade-off between security, cost, and scalability for their specific use case, such as high-frequency trading or NFT minting.
key-features
SCALABILITY ENGINE
Key Features of StarkEx
StarkEx is a validity rollup (ZK-Rollup) engine that provides secure, high-throughput scaling for applications on Ethereum and other L1s. It uses STARK proofs to batch transactions off-chain.
02
High Throughput & Low Gas Fees
By batching hundreds to thousands of transactions into a single STARK proof, StarkEx dramatically reduces the per-transaction cost and latency on the base layer (L1). This enables:
- High TPS: Supports applications like order-book DEXs and NFT minting.
- Predictable Fees: Users pay minimal fees, with bulk settlement costs amortized across the batch.
- Instant Confirmation: Transactions achieve finality off-chain before the proof is settled.
03
Data Availability Modes
StarkEx offers flexibility in how transaction data is made available, balancing cost and security:
- Rollup Mode (ZK-Rollup): Full transaction data is posted to L1 as calldata, ensuring maximum security and Ethereum-level availability.
- Validium Mode: Only proof is posted to L1; data is kept off-chain by a Data Availability Committee (DAC) or on a separate data availability layer, for lower costs but different trust assumptions.
04
Application-Specific Scaling
StarkEx is designed as an engine or SDK for building custom, high-performance applications ("app-chains"), not a general-purpose L2. It powers:
- dYdX: A perpetual futures exchange (V3 used a StarkEx-based chain).
- Immutable X: An NFT marketplace and gaming platform.
- Sorare: A fantasy football NFT game.
- rhino.fi: A DeFi aggregation layer.
06
Permissioned Provers & Decentralization
In its common deployment, StarkEx utilizes a permissioned prover operated by StarkWare to generate STARK proofs efficiently. This is a performance optimization. The system's security does not rely on this prover's honesty, as any invalid proof would be rejected by the on-chain verifier. The path to decentralization involves opening the prover network and potentially moving to a shared sequencer model.
deployment-modes
ARCHITECTURE
StarkEx Deployment Modes
StarkEx is a validity-rollup engine that can be deployed in different operational configurations, each offering a distinct trust and data availability model for the applications built on top of it.
03
ZK-Rollup
A StarkEx mode where all transaction data is posted on the Ethereum L1. This provides the highest level of security and censorship resistance, as anyone can reconstruct the state from public data, but it incurs higher gas costs.
- Data Availability: Full data on Ethereum.
- Trust Model: Inherits Ethereum's security; no additional committees.
04
Data Availability Committee (DAC)
A set of trusted entities that sign off on the availability of data in Validium mode. The DAC's signatures are included in the validity proof submitted to L1. If the committee withholds data, users cannot exit their funds, making its honesty critical.
- Role: Guarantee off-chain data availability.
- Members: Typically includes the operator and independent parties.
06
On-Chain vs. Off-Chain Data
The core distinction between deployment modes. On-chain data (ZK-Rollup) ensures permissionless exits and maximum security. Off-chain data (Validium) sacrifices this for lower cost, relying on external attestations.
- Security Property: Determines the liveness requirement for withdrawals.
- Cost Driver: Data publishing is the primary L1 expense.
ecosystem-usage
APPLICATION LAYER
StarkEx Use Cases & Ecosystem
StarkEx is a validity rollup engine that provides high-throughput, low-cost scaling for specific applications. This section details its primary implementations and the key infrastructure that supports its ecosystem.
01
Perpetual & Spot Trading (dYdX, ImmutableX)
StarkEx powers high-performance decentralized exchanges (DEXs) for both perpetual futures and spot trading. It enables:
- Non-custodial trading with centralized exchange-like speed and low fees.
- Massive scalability by batching thousands of trades into a single STARK proof.
- Advanced order types like limit orders and conditional transfers.
Platforms like dYdX (v3) used StarkEx to become a leading perpetuals DEX before migrating to its own chain, while ImmutableX uses it for NFT market liquidity.
02
NFT Minting & Trading (ImmutableX, Sorare)
StarkEx is the foundational scaling solution for leading NFT gaming and collectibles platforms. It solves critical Web3 gaming pain points:
- Gas-free minting and trading: Users pay no gas fees for most transactions.
- Instant trade confirmation with full self-custody of assets.
- High throughput to support millions of users and in-game microtransactions.
ImmutableX is the premier layer for Web3 games, and Sorare runs its global fantasy football NFT game on StarkEx, demonstrating its capacity for mainstream applications.
03
Payment & Wallets (Argent X, Braavos)
StarkEx's architecture enables smart contract wallets with superior user experience and security on StarkNet. Key features include:
- Account abstraction: Social recovery, multi-signature schemes, and transaction batching are native.
- Reduced gas costs: Complex wallet logic is executed off-chain, with only a proof submitted on-chain.
- Enhanced security: Users can set spending limits and use hardware signers.
Wallets like Argent X and Braavos leverage this to provide a seamless and secure gateway to the StarkNet ecosystem.
04
The SHARP Prover (Shared Prover)
SHARP (SHARed Prover) is the critical, decentralized proving service that underpins StarkEx and StarkNet. It is the engine that generates STARK proofs.
- Proof aggregation: Bundles transactions from multiple, independent applications into a single proof for maximum efficiency.
- Cost amortization: The high cost of proof generation is shared across all applications, driving down fees.
- Decentralized network: Operated by a permissionless set of participants, ensuring liveness and censorship resistance.
05
Volition & Data Availability Modes
StarkEx pioneered Volition, a hybrid data availability model that gives applications granular control over security and cost. Users or apps can choose per transaction:
- Rollup mode: Data is posted on-chain (Ethereum). Highest security, higher cost.
- Validium mode: Data is held off-chain by a Data Availability Committee (DAC). Lower cost, with slightly different trust assumptions.
This flexibility allows platforms like ImmutableX to offer gas-free trading (Validium) while enabling users to opt for Rollup security for high-value assets.
06
Cairo & The STARK Stack
StarkEx applications are built using the STARK-based software stack.
- Cairo: The purpose-built, Turing-complete programming language for writing provable programs (e.g., exchange logic, AMMs).
- STARK Proof System: A cryptographic proof that allows one party to prove to another that a computation was executed correctly without revealing the underlying data.
- Sequencer & Prover: The off-chain components that process transactions, generate execution traces, and create the STARK proof for Ethereum settlement.
This stack provides the foundation for building scalable, secure applications.
VALIDIUM VS. ZK-ROLLUP
StarkEx vs. StarkNet: A Comparison
A technical comparison of StarkWare's two primary scaling solutions, highlighting their architectural differences and use cases.
| Feature | StarkEx (Validium) | StarkNet (ZK-Rollup) |
|---|---|---|
Core Architecture | Application-Specific Validity Proof Engine | General-Purpose Decentralized ZK-Rollup |
Data Availability | Off-chain (Data Availability Committee) | On-chain (Ethereum L1) |
Sovereignty | Managed by application operator | Decentralized, governed by STARK token |
Development Model | SaaS for specific dApps (e.g., dYdX, Immutable) | Open network for permissionless smart contracts |
Throughput (TPS) | ~9,000+ (per application) | ~100-300 (network-wide) |
Withdrawal Safety | Trusted Data Availability Committee | Cryptoeconomically secure via L1 |
Use Case Focus | High-throughput trading & gaming | General-purpose DeFi & composability |
Settlement Layer | Ethereum Mainnet | Ethereum Mainnet |
STARKEX
Frequently Asked Questions (FAQ)
Common questions about StarkEx, the validity-rollup and validium engine powering high-throughput dApps on Ethereum.
StarkEx is a permissioned scaling engine developed by StarkWare that uses STARK proofs to batch thousands of transactions off-chain and submit a single cryptographic proof to Ethereum. It operates primarily in two modes: a Validity Rollup (zk-Rollup), where data is posted on-chain, and a Validium, where data is kept off-chain by a committee. The core mechanism involves a Prover generating a STARK proof attesting to the correctness of a batch of transactions, and a Verifier smart contract on Ethereum that validates this proof, ensuring integrity without re-executing all transactions.
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