Slither is a free, open-source static analyzer for Solidity smart contracts, built for developers and security engineers who want to catch bugs before code reaches the blockchain. It is written in Python and runs from the command line, so it fits naturally into a Windows development setup alongside tools like Hardhat or Foundry.
If you are building Ethereum-compatible applications or reviewing contracts that use ERC-20 tokens, Slither gives you a fast first pass over the codebase. It reads your source, builds an internal representation of the logic, and reports patterns that commonly lead to vulnerabilities. Because it runs in seconds, many teams execute it on every commit rather than only before an audit.
What Is Slither and Who Is It For?
Slither is a static analyzer, which means it examines source code without running it. Instead of executing a contract on a test network, it reads the code, builds a model of how functions and state variables interact, and checks that model against a library of known vulnerability patterns.
The tool is aimed at smart contract developers who want quick feedback during writing, security engineers performing audits, and teams maintaining projects over time. A developer can run it locally on Windows while writing a token contract, and an audit team can run it on a full repository before a manual review begins.
Because it is open source and free, it is also commonly used by students and researchers learning how Solidity vulnerabilities work.
How Static Analysis Fits Into Smart Contract Security
Smart contracts are difficult to fix after deployment. Once code is live on a blockchain, bugs often cannot be patched without migrating funds or building a new contract. This is why security work is usually front-loaded, with testing and analysis happening before release.
Static analysis is one layer of that process. It is fast and catches common mistakes such as unchecked return values, incorrect access control or patterns associated with reentrancy. It does not prove a contract is correct, and it cannot understand business logic the way a human reviewer can.
For this reason, most security practitioners combine several approaches: static analysis for broad coverage, fuzzing for edge cases, and manual review for logic and design. Slither typically sits at the first stage of that pipeline.
Practical Use Cases for Slither on Windows
A common scenario is a developer working on an ERC-20 token using a Windows machine with Python installed. After writing a new function, they run Slither from the terminal against the project folder. Within seconds, the output flags a state change that happens after an external call, prompting a rewrite before the code is committed.
Another scenario involves a team adding Slither to their continuous integration system. Each pull request triggers an analysis run, and new findings are reported as annotations. Reviewers can then decide whether a flagged pattern is a real risk or an acceptable design choice.
Security researchers also use Slither to triage large codebases. Running the printers gives a quick map of contract inheritance and function visibility, which helps them decide where to focus manual review time.
Key features
Low False-Positive Detection
Precise Error Location
Continuous Integration Ready
Built-in Printers
Python Detector API
Broad Solidity Version Support
SlithIR Intermediate Representation
Fast Execution
GitHub Code Scanning Integration
Vyper Support
Supported coins
Slither's documentation mentions Ethereum (ETH), Optimism and ERC-20 tokens among the networks and asset standards it is commonly used with. Because it analyzes Solidity and Vyper source code, its applicability depends on the language of the contracts you are reviewing rather than on any single chain.
How to install Slither on Windows
- 1
Check Prerequisites
Slither is written in Python, so you need a working Python environment on Windows. The recommended approach is to install the uv package manager, which handles Python versions and tool installation cleanly. You also need the Solidity compiler dependencies available, because Slither relies on the solc abstract syntax tree to read contracts.
- 2
Get the Program From the Official Source
Download only from the official website or from the project's GitHub repository at github.com/crytic/slither, and use the Releases page to pick a stable version. Verify the file you receive against the published SHA-256 checksum or signature when one is provided.
- 3
Install Slither
Open a terminal and install Slither using uv, following the project's current installation instructions. Once the install completes, confirm it works by running the slither command with the help flag to view available options.
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Verify the Installation
Navigate to a Solidity project folder that contains a Hardhat or Foundry configuration, then run Slither against it. If the tool reports detector output or a clean run, the installation is working. Errors about missing compiler dependencies usually mean the build environment needs adjustment.
System requirements
- Windows with a working Python environment
- uv package manager (recommended for installation)
- Solidity compiler dependencies available so the solc AST can be read
How to use Slither
Slither is run from the command line, and its most common use is pointing it at a project directory. The basic workflow is simple, but getting useful results depends on setting the analysis up correctly for your project structure.
- Open a terminal in the root of your smart contract project, such as a Hardhat or Foundry repository.
- Make sure dependencies are installed and the project compiles, since Slither needs the compiled Solidity information to analyze it.
- Run the slither command followed by the target path, for example the project root, to start a full analysis.
- Read the detector output carefully, noting the file, line and function that each finding points to.
- Use the printers when you want a structural overview, such as inheritance or function visibility, before diving into individual findings.
- Review each finding manually to decide whether it is a real vulnerability, a false positive, or a deliberate design choice.
- Fix confirmed issues, then rerun the analysis to confirm the finding is gone and no new ones appeared.
- Optionally, add Slither to your continuous integration pipeline so every pull request is checked automatically.
Treat the output as a starting point for review rather than a final verdict. Combining it with tests and manual inspection gives the most reliable results.
Pros & cons
- Free and open source, with the source code publicly available on GitHub
- Fast analysis, typically under one second per contract
- Precise location of issues in the source code
- Integrates with Hardhat, Foundry and CI pipelines
- Extensible through a Python detector API
- Supports both Solidity and Vyper contracts
- Static analysis cannot verify business logic or prove correctness
- Requires a working Python and compiler environment, which can take setup time on Windows
- Results still need manual review to separate real issues from false positives
- Command-line focused, so teams wanting a graphical interface may need other tools
Is Slither safe?
Slither is a read-only analysis tool and does not handle private keys, seed phrases or funds, which keeps its security risks low compared with wallets or trading bots. The main risk is installing a tampered copy. Download only from the official website or the GitHub Releases page at github.com/crytic/slither, and verify the SHA-256 checksum or signature when one is published. Be cautious of third-party websites offering modified installers. Because the project is actively maintained, check the Releases page periodically for the latest version and security updates before relying on it for an audit.
- Official source only. Download from github.com/crytic/slither. Ignore ads and lookalike domains.
- Check the SHA-256. Compare the installer hash with the value the developer publishes before running it.
- Never share your seed phrase. No developer, support agent or website — including CryptApps — will ever ask for it.
Alternatives
Slither is one of several tools aimed at smart contract security, and the right choice depends on what you need. It focuses on fast, broad static analysis of Solidity and Vyper, with strong CI support and a Python API for custom detectors. Aderyn is a Rust-based static analyzer offering a similar role, so teams sometimes compare the two on speed and rule coverage. Echidna and Medusa are fuzzers that generate random inputs to test properties, which answers a different question than static analysis. Halmos performs symbolic testing, exploring many execution paths mathematically. Many security teams use Slither alongside one of these tools rather than choosing only one.
Specifications
- Price
- Free
- Type
- Open source
- License
- —
- Latest version
- 0.11.6
- Last update
- 29 Oct 2026
- Windows support
- Likely (builds for Windows; check releases)
- Source code
- github.com/crytic/slither
Frequently asked questions
Yes. Slither is open source and free to download and use. Its source code is publicly available on GitHub, so you can inspect how it works and contribute to its development.
Slither can be installed and run on Windows, as it is written in Python and builds for Windows environments. Check the project's Releases page and installation instructions for the current setup steps, since some dependencies require a properly configured Python environment.
Slither itself does not handle keys or funds, so the main risk is downloading a modified copy. Always install from the official GitHub repository or website, and verify the file's checksum or signature when available to make sure it has not been altered.
Slither analyzes Solidity and Vyper source code, so it is applicable to Ethereum and other EVM-compatible chains whose contracts are written in those languages. Its documentation also mentions Optimism and ERC-20 tokens as common contexts for its use.
No. Slither detects known vulnerability patterns and flags suspicious code, but it cannot understand the intended business logic of a contract. It should be combined with testing, fuzzing and manual review for thorough coverage.
Slither works with projects built using Hardhat and Foundry, so you can run it on the same repository. In a CI pipeline, you add a step that runs the analyzer after compilation, and failures can block merges that introduce new findings.
Yes. Slither provides a Detector API in Python that lets you write custom analyses. This is useful when your project follows specific rules that the built-in detectors do not cover.
Slither is accessible to developers who are comfortable with the command line and basic Solidity. Beginners can benefit from its clear output and printers, but should learn common vulnerability classes alongside using it, since the findings require interpretation.
Verdict
Slither is a strong choice for Solidity and Vyper developers who want fast, free static analysis that fits into daily development and CI workflows. It is especially useful for teams that value precise issue locations and the ability to add custom Python detectors. It is not a replacement for fuzzing or manual audits, but as a first layer of review it is among the most practical options available for Windows users.