Security & testing

CodeTracer is a user-friendly time-traveling debugger designed to support a wide range of web3 programming languages.

EDB is a source-level debugger for Solidity execution with stepping, locals, watches, and breakpoints when you need IDE-grade visibility into contract behavior onchain or in tests.

Simbolik is a powerful Solidity debugger that combines traditional breakpoint debugging with symbolic execution, enabling developers to explore every possible execution path and uncover vulnerabilities with precision. Available as a VSCode extension, Simbolik integrates seamlessly into existing workflows, offering breakpoint-style debugging, Solidity and EVM-level inspection, and formal verification capabilities.

Abi Ninja is a browser UI for calling contracts with known ABIs, pasted ABIs, or decompiled bytecode, with proxy-aware reads across many networks including your locally running Hardhat or Anvil node.

4byte.directory maps four-byte function selectors and 32-byte event-signature hashes to their human-readable signatures. Builders query it when decoding calldata or logs from contracts without a published ABI.

The ABI Calldata Layout Visualizer decodes ABI calldata and draws its byte layout, showing where heads, tails, and offsets sit in the encoded payload. Builders open it when a plain decoder does not explain why an encoding is wrong.

evm-storage turns a transaction hash into readable state diffs and can list a contract's full storage. Builders install the command line tool when they need to see exactly which storage slots a call changed.

EVMConnector is a browser workspace for calling contract functions on any EVM chain, with saved contracts and shareable call links. Builders use it to drive a contract without writing a script.

forky is a fork choice viewer for the Ethereum beacon chain. Consensus client developers self-host it or use the public instances to see and debug fork choice behavior on mainnet and testnets.

geas, the Good Ethereum Assembler, is an assembler for writing raw EVM bytecode by hand, maintained by a go-ethereum core developer. It is used for EIP test cases and other low-level contract work.

hardhat-tracer is a Hardhat plugin that prints internal calls, events, and storage operations for a transaction in the console. Hardhat users install it to see what actually happened inside a failing test transaction.

The HashEx ABI Encoder is a web form that ABI-encodes constructor and function arguments from a pasted signature and values. Builders use it when they need encoded arguments and are not at a terminal.

heimdall-rs is a Rust EVM toolkit that disassembles bytecode, decompiles contracts, generates control flow graphs, and decodes calldata and traces. Builders reach for it when they need to understand a contract that has no published source.

pyevmasm is a Python disassembler and assembler for EVM bytecode from Trail of Bits. Analysis scripts import it to turn bytecode into instructions and back.

Radar, from Auditware, is a static analysis tool that covers Solidity as well as Rust, Anchor, and Stylus contracts. Auditors run it to get findings across a mixed contract codebase.

A calldata decoder that also unwraps nested function calls. Builders open it when a flat decoder leaves the inner calls of a batched or forwarded transaction unreadable.

scopelint is an opinionated formatter and linter for Foundry Solidity projects. Builders install it to hold a codebase to the ScopeLift conventions.

Semgrep is a pattern-based static analysis tool with rulesets for Solidity vulnerabilities. Builders run those rules over a codebase to catch known vulnerable patterns and style issues before review.

SmartContractGUI turns an uploaded ABI into an interface for reading from and writing to that contract on any EVM chain. Builders use it when they have an ABI but no frontend.

sol-profiler is a command line tool that lists a Solidity contract's methods with their visibility, mutability and modifiers. Reviewers run it to see the surface of a contract at a glance.

sol2uml generates UML class and storage-layout diagrams from Solidity source or from verified contracts. Builders run it to see contract relationships and how state variables are packed into storage.

Tenderly provides transaction simulation, trace debugging, alerting, and Virtual TestNets for contracts. Builders use it to replay a failing transaction, watch deployed contracts, and test against a forked network.

The Tenderly CLI is the command line client for Tenderly, pushing contracts for verification and driving error tracking, monitoring, and alerting. Builders install it to run those steps from a terminal or a continuous integration job.

tracoor is an explorer for beacon states and execution traces. Client and protocol developers self-host it to inspect block and state traces on devnets and testnets.

Web3Client is a browser tool for creating, testing, and sharing contract ABIs and the calls made against them. Builders use it to work out a call and hand the result to someone else.

Web-based transaction debugger and simulator for the EVM. Open-source and self-hostable. Inspect variable states at every step, simulate transactions before deploying, and profile gas usage. Supports any RPC provider.

viem-tracer augments a Viem client so failed ethestimateGas and ethsendTransaction calls automatically include human-readable trace output decoded with sourcify.dev, and it adds typed helpers around debug_traceCall so developers can inspect execution without leaving their existing RPC stack.

EVMole extracts function selectors, arguments, and control flow from raw EVM bytecode, including contracts with no verified source. Builders point it at an unknown contract to work out what its functions take.

revm-inspectors is a Rust crate of EVM execution hooks and tracing built on revm, and it powers call tracing in Reth and Foundry. Rust builders import it to build their own tracers and debuggers.

hardhat-gas-reporter is a Hardhat plugin that reports gas used by each function call and deployment while the test suite runs, with optional fiat cost estimates. Hardhat users add it when they need to see the gas impact of a change in the test output.

Slippy is a Solidity linter for static analysis of smart contracts. Teams install the npm package to lint contracts as part of a build.

Chimera is a framework to write Solidity tests in foundry and be able to reuse them with other Open Source Tools such as Echidna, Medusa, Halmos and Kontrol

Slither is Trail of Bits' Python static analysis engine for Solidity and Vyper: run it in CI to fire detectors, print structural views of contracts, or script custom checks over whole codebases.

Synpress layers Playwright with Ethereum-aware browser automation so you can end-to-end test dapps, including wallet popups and chain switches, in CI.

Aderyn is Cyfrin's open-source, Rust-based solidity smart contract static analyzer designed to help protocol engineers and security researchers find vulnerabilities in Solidity code bases

Titanoboa is an interactive Vyper interpreter and test harness for fast feedback loops when you are experimenting with contracts outside a full Foundry loop.

Medusa is a stateful smart contract fuzzer inspired by Echidna. It provides parallelized fuzz testing of smart contracts and the verification of advanced smart contract invariants.

solidity-coverage provides smart-contract code coverage for the Hardhat developer platform. It's highly accurate, supports full viaIR solidity compilation and a large set of solidity-specific code branch patterns. It's installed on ~230k Github projects and is downloaded ~100k times a week from NPM.

hevm is an open source, state-of-the art, fast symbolic and concrete EVM execution engine that can find issues in smart contracts. Through its symbolic execution and analysis system, hevm can symbolically, semi-concretely, or concretely execute contracts to find bugs, or compare two different contracts for discrepancies, performing equivalence checking.

Crytic-Properties is a suite of re-usable security tests for some of the most widely used token standards such as ERC20, ERC721, ERC4626, and more.

A smart contract test generator based on the Branching Tree Technique.

Assertoor runs configurable checks and assertions against a live Ethereum devnet to validate its behavior. Client and devnet teams use it to confirm a running network is healthy, in the same family as Hive.

contender from Flashbots is a load-testing tool that floods EVM execution nodes over JSON-RPC and benchmarks the results. Teams benchmarking a client point it at an endpoint to generate load and measure throughput.

Echidna is a property-based and grammar fuzzer for Ethereum smart contracts. Builders and auditors write properties with it to find inputs that break contract invariants.

eth-tester is a pluggable in-memory Ethereum backend used by web3.py for fast unit tests. Python builders import it when tests should run against a simulated chain instead of a node.

ItyFuzz is a bytecode-level smart-contract fuzzer that combines fuzzing with symbolic analysis. Builders and auditors run it against EVM bytecode when source-level fuzzing is not enough or no source is available.

spamoor is a configurable Ethereum transaction generator for load-testing testnets and devnets with realistic traffic. Teams point it at a network to see how it behaves under sustained transaction volume.

goevmlab is an EVM fuzzing and differential testing lab built by a go-ethereum core developer. EVM implementers use it to fuzz their own implementation and compare its behavior against others to find divergences.

Hive is an end-to-end integration test harness that runs Ethereum clients in Docker across simulator scenarios. Client teams use it to check that implementations agree with each other.

KEVM is the K-framework executable semantics of the EVM: point it at bytecode when you need conformance-checked execution, symbolic exploration, gas reasoning, or proofs that track Ethereum's rules closely.

hax is a tool for high assurance translations of a large subset of Rust into formal languages such as F* or Rocq.

Kontrol lifts Foundry property tests into KEVM-backed proofs so you can chase formal guarantees with less hand-written specification work than raw KEVM alone.

Act is Ethereum's declarative specification language and toolchain for describing all behaviors of an EVM program so SMT solvers, theorem provers, or economic analysis tools can reason about bytecode-level correctness and incentive compatibility, including automatic refinement proofs against concrete implementations.

Certora AutoProver is an AI bot that automates parts of formal verification for smart contracts. Verification engineers use it to generate and run checks with less manual specification work.

Verifereum connects Ethereum smart contracts to HOL4-backed theorem proving so you can aim at very strong correctness claims when automated SMT approaches are not enough.

Certora Prover is a cloud formal-verification service that checks specifications written in CVL against deployed contract code. Verification engineers use it to prove that a contract holds stated properties for all inputs.