Apollo traces EVM execution step by step to uncover edge cases, gas inefficiencies, and unexpected opcode behavior.
A complete debugger built for developers, auditors, and security researchers working with Ethereum smart contracts.
Navigate forward and backward through every opcode. Auto-play with adjustable speed, or jump to specific instructions.
Inspect every layer of EVM state in real time. See which values are pushed, popped, and how storage slots evolve.
Set breakpoints on opcodes, program counters, storage slots, memory ranges, or transient storage changes. Stop exactly where it matters.
Track gas consumption per instruction and per contract. Identify bottlenecks and optimize your smart contract execution costs.
View decoded bytecode with highlighted execution, visit counters, and automatic tracking of cross-contract calls.
Filter opcodes, skip contracts, and label addresses with aliases. Customize the debugger to focus on what you care about.
Three steps to debug any EVM transaction on any network.
Paste a transaction hash and the RPC URL of any EVM-compatible node. Apollo fetches the full execution trace.
Step through opcodes one by one. Inspect the stack, memory, and storage at every point. Set breakpoints to jump to key moments.
Identify gas inefficiencies, trace unexpected behaviors, and debug reverts. Export your findings and fix your contracts.
Debug failing transactions and understand exactly why a REVERT happened, what storage changed, and where gas is spent.
Analyze exploit transactions opcode by opcode. Trace cross-contract calls, delegatecalls, and reentrancy patterns.
Verify contract behavior against specifications. Step through edge cases and validate that invariants hold.
Learn EVM internals by watching real transactions execute. See how Solidity compiles to opcodes and how the stack machine works.
Apollo is free to use. Load a transaction hash and start debugging in seconds.