S-two officially launches on the Starknet mainnet, ushering in the era of the fastest STARK prover in history.
StarkWare's new open-source prover—S-two (pronounced Stew)—has now completely replaced Stone, providing proofs for every block on Starknet.
This is a revolutionary upgrade in the ZK field:
🚄 1/ Speed: The world's fastest ZK Prover
Based on Circle STARKs + M31 small prime field design, implemented in Rust, it increases proof generation speed by an order of magnitude.
Proofs that used to take minutes are now completed in seconds.
🔒 2/ Lower Proof Costs
Faster = More Costs = More Possibilities.
Privacy DeFi, real-time data authentication, on-chain identity, zkML, etc.—things that were previously infeasible due to high costs can now be truly implemented.
📱 3/ The Client-side Proving Era
S-two is fast enough to generate proofs on your mobile phone.
This means:
• Private ERC20 transfers (hidden address and amount)
• Private transactions / Dark pools
• Privacy-preserving identity verification such as age/uniqueness/credentials
• Verifiable AI/ML inference results
Truly bringing ZK to the "user end".
🧵 4/ The Starting Point of Decentralized Proving
Lower costs mean that in the future, any sequencer can run its own prover.
This is the most crucial link in Starknet's decentralized roadmap.
📱 5/ Real-world Validation Already Available: Kakarot's Large-Scale User-Side Validation
Kakarot's experiments have already enabled millions of proofs to be generated locally on thousands of mobile phone models. This is not a concept; it has already happened.
🔮 6/ Next Steps
• Further reduction in proof costs
• Emergence of numerous new privacy/identity/zkML applications
• Starknet's move towards a fully decentralized Prover network
• A stronger developer toolchain
The launch of S-two signifies a qualitative leap in Starknet's scalability, privacy, and security. The true explosion of ZK applications is happening right now.

