Introducing SXT Chain

As blockchain technology accelerates, it’s hindered by three key issues: poor user and developer experiences, fragmented blockchain ecosystems, and smart contracts’ inability to process data at scale. To realize the vision of DeFi and unlock the potential of onchain apps, we knew these issues needed to be solved. Since day one, Space and Time has been focused on delivering trustless, cross-chain data processing to make smart contracts “smarter” and ultimately make it easier for devs to build onchain. Today, we’re proud to introduce SXT Chain, a blockchain for ZK-proven data: now live in testnet. 

The problem: Smart contracts have no context

Until now, smart contract devs have been building with their hands tied behind their backs, stuck with self-referential opcodes which can’t access even the most basic answers about activity onchain. Historical transactions, cross-chain activity, or offchain data sources can’t be natively queried by a smart contract, which significantly limits the design space for onchain apps.

The next generation of DeFi

As a result, DeFi instruments have remained largely stuck behind their TradFi counterparts. While the first generation of DeFi brought us Uniswap, Aave, and yield farming, we believe that the next generation will bring much more complex financial instruments onchain, such as cross-chain derivatives, onchain lending markets with dynamic interest rates, and tokenized real-world assets. Unlocking these use cases requires a trustless, crypto-native query engine that can give smart contracts the proper context to facilitate more sophisticated DeFi. Chainlink ushered in DeFi summer by providing aggregated data points such as price feeds, and SXT is expanding on that vision with a SQL database that allows smart contract developers to access the entire history of Ethereum and run SQL processing on it.

Powering AI x blockchain

Solving the query engine problem for smart contracts is even more important as AI accelerates and new AI x blockchain use cases emerge. In the AI-powered future, apps and agents will need a way to handle financial transactions autonomously. Blockchain offers a permissionless and trustless way to facilitate transactions via smart contracts. Your AI apps will use crypto to handle things like escrow, loans, bets, trades, tipping a creator, or simply accepting payment.

But data that’s generated by your app, like clickstreams or user activity, is too sizable and not necessarily high-value enough to be stored and secured onchain and should instead live in a database that processes data efficiently. However, centralized databases can’t be trusted by smart contracts. In order to power the future of AI and to usher in the next generation of DeFi, crypto needs a ZK-proven database that can deliver trustless information around what’s happening both onchain and in your app to smart contracts (already loaded with verifiable data from every popular blockchain).

The solution: SXT Chain and Proof of SQL

SXT Chain is essentially a decentralized database that witnesses data from onchain and offchain sources, secures it, and stores it for devs to query using Proof of SQL, SXT’s ZK coprocessor.

Collecting data: blockchain indexers

Indexers collect data from major chains, including Ethereum, ZKsync Era, Bitcoin, Sui, Aptos, and Polygon, and ingest it into the network. Because the indexers begin ingestion from genesis block, SXT essentially collects an entire copy of each chain—updated in real time—and stores it in queryable format. Devs can also request indexing for their own specific smart contract events to be written to new, custom tables in SXT. 

We’ve built these indexing nodes to be very lightweight, so that anyone can run them on hardware as simple as a MacBook. We’re excited to open up community-run indexing later in the testnet as we work toward decentralizing SXT.

Witnessing, signing, and storing data: validators

The primary purpose of SXT Chain validators is to witness and secure the data ingested into the network. As the indexers collect data from the chain, the validators threshold-sign commitments on it and store both the data and commitments across a decentralized network of database nodes. Validators can also sign and store offchain data inserted by a client, such as real-world asset data, market data, DePIN node data, insurance telemetry, LLM logging/auditing, or prediction market outcomes.

Querying and proving data: ZK coprocessor

Proof of SQL is SXT’s sub-second ZK coprocessor, which serves as a ZK-proven query engine for data on SXT Chain. Devs can query this data with a familiar SQL interface and generate a ZK proof that their queries (and the underlying data) are accurate and haven’t been manipulated. Today, you can run analytic queries against 200k rows of data with Proof of SQL sub-second, and it’s only getting faster. You can learn more about Proof of SQL by reading the whitepaper. 

Verifying proofs and delivering query results onchain: Chainlink Functions

To optimize ZK-proof verification, SXT Chain is integrated with the Chainlink Network, offering developers an efficient and cost-effective consensus-based way to ZK-verify query results. The integration also includes native support for Chainlink Functions, allowing developers to directly deliver ZK-proven query results from SXT to their smart contracts. Smart contract developers that are already familiar with Chainlink can create a functions job that queries SXT Chain like any normal third party API, except that in this case the Chainlink Network will verify the ZK proof before relaying the result onchain. SXT acts as a trusted ZK-proven database for Chainlink developers, expanding the scope of what they can build onchain. 

Deploying smart contracts & settling the network: ZKsync ZK Rollup

To support SXT Chain, SXT also includes its own ZK rollup, built on ZKsync’s Elastic Chain stack, as its smart contract execution layer. The rollup enables devs to easily deploy Solidity smart contracts on top of SXT. It will also include native DeFi apps that handle client payments, staking, and node operator coordination for the network, as well as third-party DeFi apps for liquid staking, derivatives and data-intensive apps.

The result: Making smart contracts smarter

All together, SXT specifically allows smart contracts to “ask ZK-proven questions” regarding activity on their own chain, other chains, or offchain. For example, a smart contract can request the SQL equivalent of:

• Liquidity Pools TVL: “Show me all liquidity pools with a TVL greater than $1M that were deployed at least one month ago.”
• Liquidity Pools Collateral: “Sum up the total collateral available right now in all liquidity pools our protocol operates across the following four chains…”
• DEX Loyalty Program: “Given that wallet ‘xyz’ is currently attempting a trade, show me the number of prior trades this wallet has already made with DEX liquidity pool address ‘xyz’.” (In order for the DEX contract to apply a discount or reward to the current trade).
• Avg. Lending Rates Onchain: “Show me the volume-weighted average lending rate for USDC on Aave, Maker, and Compound right now.”
• Wallets with Token Balance Criteria: “Show me all wallets that have a balance > $1000 of $LINK token and have interacted with at least one Chainlink smart contract.”
• Bridge Transactions: “Show me all transactions across ‘xyz’ bridges that moved at least $1M of tokens per wallet from Chain A to Chain B.”
• Gamer Achievements: “Show me all gamer wallets that have at least 2 hours of playtime in-game, have minted our NFT, and played with ‘xyz’ weapon.”
• CeFi Options Markets: “Give me the at-the-money implied volatility of Bitcoin call options expiring end-of-year averaged (volume-weighted) across Deribit and Binance.”
• Trustless ETFs/Indexes: “Create a volume-weighted index of the following 10 tokens calculated from price oracle SQL calculations and deliver it to my contract as a single price index…”
• Airdrop Criteria: “Roll up the wallet transaction histories of all wallets that meet the following criteria for my airdrop…”
• Governance Engagement Score: “Roll up engagement scores for wallet activity that meets the following criteria… where volume transacted in ‘xyz’ token, onchain governance voting participation, and past NFT ownership will contribute to rewards/discounts associated with a wallet engagement score.”
• Governance Qualification: “Find all wallets that have participated in governance votes and rank them with a cross-section of the amount of ‘xyz’ token held and how long it’s been held.”
• Weather (Onchain Insurance Payouts): “Show me the average wind speeds across all reported weather stations in Miami, Florida today.”
• Github Activity (Open Source Contributions): “Rank developer wallets by their total code contributions through ingested Github activity data.”
• Oracle Activity: “Show me total volume of oracle requests over the last hour that did not complete the request within 2 blocks.”
• Pricing Blockspace: “Determine blockspace ‘market rates’ by averaging transaction gas fees along with block header metadata.”
• NFT Floor Prices: “Look at NFT trading information onchain and find the current average floor price for collection ‘xyz’.”
• Perp Funding Rates: “Calculate the implied volatility of both $ETH and $BTC using onchain perpetual futures funding rates as a leading indicator.”
• Ethereum Staking Rates: “Show me the risk-minimized average returns on Ethereum liquid staking via Lido over the past hour.”

SXT Chain Roadmap

Today, SXT supports:

• Indexing for Ethereum mainnet, ZKsync Era, Bitcoin, Sui, Aptos, and Polygon
• Proof of SQL queries (ZK coprocessor)
• Tamperproof SQL database

We’re excited to continue building with the community throughout the testnet to enable:

• Onchain crypto payments for your queries
• EVM-based onchain verification for Proof of SQL
• Running ZK-proven queries and verifying them on your own client device
• Community-run indexing nodes 
• Launching a permissionless SQL database and decentralizing the network

Get involved

SXT Chain is now live in testnet, and we’re excited to build alongside our ecosystem and community to drive a trustless, data-driven future for blockchain technology. To learn more about running a node, building an app, or joining our community, visit spaceandtime.io/testnet.