# BlockDB Blog

> Lineage-verified DeFi datasets for quant funds and AI teams. Institutional-grade on-chain data with row-level proof-of-derivation via deterministic _tracing_id hashes.

BlockDB delivers transaction-level DeFi datasets across EVM chains (ETH, BSC, Base, Arbitrum, Unichain, Avalanche, Polygon, Celo, Linea, Optimism). Every row is traceable to its source on-chain event. Data is available via WSS streaming (<140 ms), SFTP, and MCP tools for AI agents.

## Articles


- [What Is Maximal Extractable Value (MEV) in Ethereum and How Does It Work?](https://blog.blockdb.io/articles/what-is-mev-ethereum): Comprehensive explainer covering MEV definition, historical context (Miner → Maximal), key players (searchers, block builders, validators, PBS), all major MEV types (arbitrage, liquidations, front-running, back-running, sandwich attacks, time-bandit attacks, oracle frontrunning), mechanics pipeline, economic consequences (gas auctions, volatility feedback loop), and market scale ($200M+ arbitrage MEV in 2021 per BIS data).


## Reference

- [BlockDB DeFi Data Glossary](https://blog.blockdb.io/articles/glossary): Authoritative definitions of key terms used in BlockDB datasets and documentation. Covers: _tracing_id, reorg handling, concentrated liquidity, sqrt_price_x96, tick, schema stability, WSS streaming, SFTP delivery, MCP tools, AMM, DEX, EVM, row-level lineage.

## Datasets

All BlockDB datasets are available for free preview at https://huggingface.co/BlockDB/datasets - no account required. The following datasets are published with 1,000+ sample rows:

- Swap-Prints: Tick-level DEX swap events (pool_address, token0, token1, amount0, amount1, sqrt_price_x96, tick, _tracing_id) across 11 EVM chains
- Liquidity-Pools-Reserves: Per-block reserve snapshots for all tracked DEX pools
- Swap-Fees: Swap fee amount and recipient per event, all fee tiers
- Liquidity-Pools-Fee-Terms: Pool fee configuration and tier data
- Liquidity-Pools: Pool metadata - tokens, factory, creation block
- ERC20-Tokens: Token metadata, total supply, decimals across EVM chains
- ERC721-Tokens: NFT contract metadata
- ERC1155-Tokens: Multi-token contract metadata
- Token-Transfers: ERC-20/721/1155 transfer events
- Raw-Transactions: Full transaction data from genesis
- Raw-Blocks: Block header data from genesis
- Raw-Logs: Event log data from genesis
- Raw-Internal-Transactions: Internal (trace-level) transaction data
- Raw-Contracts: Contract deployment data
- Raw-Function-Results: On-chain function call results

## Key Concepts

- _tracing_id: Deterministic SHA-256 hash = sha256(chain_id:block_number:tx_index:log_index). Provides row-level proof-of-derivation. Every BlockDB row carries one.
- Schema stability: Breaking changes ship as new table versions. Existing tables never change silently.
- Reorg handling: Orphaned rows flagged is_reorged=true. Canonical replacements appended with same _tracing_id structure.
- Delivery: WSS streaming (<140 ms median), SFTP end-of-day, SFTP historical, MCP tools.
- Chains: ETH, BSC, Base, Arbitrum, Unichain, Avalanche, Polygon, Celo, Linea, Optimism.

## Contact

- Website: https://www.blockdb.io
- Documentation: https://docs.blockdb.io
- Datasets (free preview): https://huggingface.co/BlockDB/datasets
- Hugging Face profile: https://huggingface.co/BlockDB
- LinkedIn: https://linkedin.com/company/blockdb
- YouTube: https://youtube.com/@Block_DB
- Get samples / contact: https://www.blockdb.io/#contact-us