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This section provides details about ChainStream’s EVM Streams via Kafka. The top-level Kafka section explains how we use Kafka Streams to deliver data. EVM blockchains produce blocks at varying intervals depending on the network. Ethereum mainnet targets ~12 seconds per block, while other EVM chains may have different block times.

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Structure of On-Chain Data

The EVM Protobuf Streams provide three main message types for different use cases:
  • BlockMessage: Full blocks with detailed transaction traces
  • TransfersMessage: Focused on token transfers with currency metadata

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Block-Level Data

Each block in the stream includes a BlockHeader with fields such as:
  • Hash: The unique identifier of the block
  • ParentHash: Hash of the previous block
  • Number: Block number/height in the chain
  • GasLimit: Maximum gas allowed in this block
  • GasUsed: Actual gas consumed by transactions
  • Time: Block timestamp
  • BaseFee: Base fee per gas (EIP-1559)
The BlockMessage also includes:
  • Chain: Information about the blockchain (ChainId, Config)
  • Uncles: Uncle/ommer blocks (Ethereum PoW)
  • Transactions: All transactions in the block
  • L1Header: For Layer 2 chains, information about the corresponding L1 block

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Transaction-Level Data

Transactions include: TransactionHeader: Core transaction data
  • Hash: Transaction hash
  • Gas: Gas limit for this transaction
  • Value: Amount of native currency transferred
  • Data: Call data for contract interactions
  • From/To: Sender and recipient addresses
  • GasPrice, GasFeeCap, GasTipCap: Fee parameters
  • Special fields for EIP-4844 blob transactions
Signature: Transaction signature (R, S, V values) Receipt: Execution results
  • Status: Success or failure
  • GasUsed: Actual gas consumed
  • Logs: Event logs emitted
Trace: Detailed execution trace
  • Calls: Internal contract calls
  • CaptureStates: State modifications

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Transfer Data

The TransfersMessage stream provides information about native token and token transfers: TokenTransfer: Records native token and token movements with:
  • Sender: Address sending tokens
  • Receiver: Address receiving tokens
  • Amount: Amount of tokens transferred
  • Id: Token ID (for non-fungible tokens)
  • Currency: Detailed token information
  • Success: Whether the transfer succeeded
TokenInfo: Metadata about each token:
  • SmartContract: Token contract address
  • Name: Token name
  • Symbol: Token symbol
  • Decimals: Token decimal places
  • Fungible: Whether token is fungible (ERC-20) or non-fungible (ERC-721/1155)

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Layer 2 Support

EVM Protobuf Streams provide dedicated fields for Layer 2 chains:
  • L1Header: Corresponding L1 block information
  • Optimism-specific fields: SequenceNumber, BatcherAddr, L1FeeOverhead, etc.
  • Arbitrum-specific fields: GasL1 for L1 data costs

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Using This Stream

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Topic Names

The EVM streams are available under different topics:
  • eth.v1.transfers.proto → TransfersMessage
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