Contract Telemetry

Tracks and logs every modification to a smart contract's storage variables and internal state. This includes monitoring for:

• Balance changes of the contract and its associated wallets.
• Updates to critical mappings, arrays, and structs.
• Access control modifications (e.g., owner changes, role assignments).
• Pause/Unpause state toggles in upgradable contracts.

Records the execution flow of transactions, providing visibility into internal function calls and cross-contract interactions. Key capabilities include:

• Input/Output parameter logging for every invoked function.
• Tracing of internal calls (e.g., delegatecall, call, staticcall).
• Identification of reverted transactions with precise error messages (e.g., custom errors, require statements).
• Mapping of caller addresses to specific actions for security and analytics.

Captures and indexes all EVM logs emitted by the emit keyword, which are the primary mechanism for smart contracts to communicate state changes off-chain. This feature:

• Decodes indexed and non-indexed event parameters into human-readable data.
• Creates a queryable history of significant contract milestones (e.g., Transfer, Approval, OwnershipTransferred).
• Enables the reconstruction of complex contract interactions by correlating events across multiple transactions.

Measures the computational cost of contract operations, providing insights into efficiency and potential optimizations. This involves analyzing:

• Gas used per transaction and per individual function call.
• Gas price trends and their impact on operation costs.
• Identification of gas-intensive functions or patterns that could be optimized.
• Correlation between input complexity and resource expenditure.

Applies heuristic and rule-based analysis to identify suspicious patterns indicative of exploits or unintended behavior. This includes monitoring for:

• Flash loan attacks and arbitrage patterns.
• Reentrancy attempts and other common vulnerability patterns.
• Unusual spikes in transaction volume or value transfers.
• Deviations from established interaction patterns with known counterparties.

Aggregates data to provide high-level operational insights into contract reliability and usage. Common metrics include:

• Transaction success/failure rates over time.
• User activity trends (unique interacting addresses).
• Throughput (transactions per block or per hour).
• Uptime and responsiveness based on successful call completion.

Transaction logs are the most critical source, containing structured data emitted by smart contracts via the emit keyword. They are stored on-chain and are the primary way contracts communicate state changes, such as token transfers, swaps, or governance votes. Key properties include:

• Indexed Parameters: Up to three parameters can be indexed for efficient filtering by external applications.
• Immutable Record: Once mined, logs are permanent and verifiable parts of the blockchain history.
• Gas-Efficient: Emitting events is far cheaper than storing data in contract storage.

Internal transactions (or message calls) trace the flow of value and execution between contracts during a single external transaction. They reveal the call graph, such as a user interacting with a DEX router that subsequently calls a pool contract and a token contract. Monitoring these is essential for:

• Composability Analysis: Understanding how protocols interact and bundle functions.
• Value Flow Tracking: Following ETH or token transfers inside complex DeFi transactions.
• Debugging & Security: Identifying unexpected or malicious contract interactions.

State changes refer to modifications in a contract's persistent storage variables (like balances, allowances, or governance proposals). While not directly emitted as events, they are inferred by comparing the state of a contract's storage before and after a transaction. This data source is vital for:

• Calculating Metrics: Determining Total Value Locked (TVL), user balances, or pool reserves.
• State Integrity: Auditing that contract logic correctly updates storage.
• Historical Analysis: Reconstructing the state of a protocol at any past block.

Call traces provide a low-level, step-by-step record of the Ethereum Virtual Machine (EVM) execution for a transaction, including every OPCODE and stack operation. Debug traces are a richer variant often available from node providers. They are used for:

• Deep Execution Analysis: Understanding exact control flow and gas consumption at the opcode level.
• Security Tooling: Powering smart contract debuggers and vulnerability scanners.
• Simulation: Testing how a transaction will execute without broadcasting it (eth_call with tracing).

Block headers and transaction receipts provide the essential metadata that contextualizes contract activity. The block header contains the timestamp, base fee, and miner. The receipt contains the transaction status (success/failure), cumulative gas used, and the bloom filter for event logs. This data is foundational for:

• Temporal Analysis: Correlating contract activity with market events or time periods.
• Gas Economics: Analyzing the cost and efficiency of contract interactions.
• Finality & Confirmation: Determining when a contract's state change is considered final.

Access to the raw data sources above is provided via a blockchain node's JSON-RPC API. Key methods for telemetry include:

• eth_getLogs: Retrieves event logs with filter parameters.
• eth_getTransactionReceipt: Gets the receipt for a specific transaction.
• trace_transaction: Returns a full call trace (requires an archive node with tracing).
• eth_getBlockByNumber: Retrieves full block data, including transactions and headers. These endpoints are the direct gateways for indexing and monitoring services to collect contract telemetry.