Solar Compiler is a free, open source Solidity compiler written in Rust. It is aimed at smart contract developers who want fast builds, low memory use and clear error messages when they compile contracts on Windows, macOS or Linux.
If you work with Ethereum contracts, you already know that compile time can slow down a test-and-fix loop. Solar is built to shorten that loop. Its authors report that, on six real-world projects, builds ran about 100 times faster on average than solc's via-IR pipeline, with a peak of 159 times on the Morpho Blue codebase. Benchmarks vary with project size and settings, so treat these figures as a guide to what to measure on your own code.
What Is a Solidity Compiler and Why Speed Matters
A Solidity compiler translates human-readable Solidity source code into bytecode that the Ethereum Virtual Machine can execute. Every time you change a contract, the compiler runs again before you can test the result. On a small project this takes seconds, but on a large protocol with many imported libraries, a slow compiler can add minutes to each iteration.
Fast compilation changes how you work. You can run tests after every small edit, catch mistakes earlier and keep your attention on the logic rather than waiting. Solar's focus on speed is aimed directly at this development loop.
Who Solar Compiler Is For
Solar is most useful for developers who build and test smart contracts professionally or as a serious hobby. Protocol teams with large codebases tend to feel compile-time pain most, because their builds touch many files and dependencies.
The project also suits contributors who want to work on compiler internals. Because the code is written in Rust and organized into libraries, a developer with Rust experience can read individual components, run them in isolation and propose improvements. Beginners who are still learning Solidity may find the readable diagnostics helpful, though they may also prefer a full IDE with guided editing while they learn the language.
Realistic Use Cases
A typical scenario is a team maintaining a lending protocol with dozens of contracts. Each change triggers a build, and the team runs a suite of unit and integration tests afterward. Replacing a slow compile step with a much faster one reduces total test time and makes continuous integration pipelines quicker to finish.
Another scenario is a solo developer working on a small token contract on a laptop. Lower memory use means the machine stays responsive while an editor, a local node and a test runner are open at the same time. A third case is benchmarking: teams evaluating compiler options can use Solar as one data point when deciding how to structure their build settings.
In all of these cases, the value depends on your project. Measure build times on your own code before deciding whether a switch makes sense.
Key Concepts: Via-IR and Compiler Pipelines
Solidity compilers process code in stages. The via-IR pipeline is an intermediate representation stage used by solc to optimize code before final bytecode is produced. It can yield more efficient bytecode but often takes considerably longer to run. That trade-off is the reason the speed comparison in the project's benchmarks is meaningful: Solar aims to deliver quick builds without giving up the practical quality you need.
When reading benchmark results, it helps to know which pipeline was used on each side, which projects were tested and whether optimization settings were matched. Asking those questions will give you a more accurate picture of what the numbers mean for your work.
Key features
Very fast compiles
Low memory usage
Readable diagnostics
Modular, library-based design
Simple, hackable code base
Support for recent Solidity
Supported coins
Solar Compiler targets Solidity source code for Ethereum-style smart contracts. It is a compiler, so it does not manage coins or networks directly; it produces the bytecode that you then deploy with other tools.
How to install Solar Compiler on Windows
PS> scoop install solar-compiler- 1
Choose your installation method
On Windows, the simplest route is the Scoop package manager. If you do not have Scoop yet, install it first from its official site, then use the command below. Alternatively, download a pre-built binary from the project's GitHub Releases page.
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Install with Scoop
Open PowerShell and run: scoop install solar-compiler. Scoop fetches the package, places the executable on your path and lets you update or remove it later with standard Scoop commands.
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Or download the binary manually
Pre-built binaries are available for Windows, macOS and Linux on the GitHub Releases page. Download the archive for Windows, extract it to a folder of your choice, and add that folder to your PATH environment variable so you can run the compiler from any terminal.
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Verify the installation
Open a new terminal window and check that the compiler responds to its version or help command. If the shell does not recognize the command, confirm that the install folder is on your PATH and restart the terminal.
System requirements
- Windows with a command-line terminal such as PowerShell
- Scoop, if you install through the package manager
How to use Solar Compiler
Solar Compiler runs from the command line. Once it is installed, you point it at your Solidity source files and let it produce the compiled output. The exact flags depend on the version you install, so check the built-in help or the project documentation for the current syntax.
A typical workflow looks like this:
- Open a terminal in your project folder, next to your Solidity files.
- Run the compiler's help command to review the available options for the version you installed.
- Compile your contracts with the input files and output settings you need.
- Read any diagnostics the compiler prints, and fix errors in your source code.
- Repeat the build after each change, comparing timings if you are evaluating performance.
- Feed the generated output into your testing or deployment tools.
Pros & cons
- Very fast compile times on large real-world projects, according to published benchmarks
- Low memory usage during builds
- Clear, expressive diagnostics
- Free and open source under permissive licenses
- Modular architecture that can be reused or extended
- Readable Rust codebase that welcomes contributors
- Easy installation on Windows through Scoop
- A command-line tool, so it lacks the guided editing of a full IDE
- Designed to be used alongside other development tools rather than as a complete environment
- Library users must pin the version carefully because the minimum supported Rust version may change
- Speed claims come from the project's own benchmarks, so your results will depend on your code
Is Solar Compiler safe?
Solar Compiler is open source, which means its source code is public for review. Still, download it only from the official GitHub Releases page or through the Scoop package manager. Before running a downloaded binary, verify its SHA-256 checksum or signature if the release provides one. Avoid mirrors and third-party download sites, since they can distribute modified files.
A compiler does not handle your wallet keys, but it does produce bytecode you may deploy to a live network. Review the output and test contracts thoroughly before deployment, and keep your development and production keys separate.
- Official source only. Download from github.com/paradigmxyz/solar. 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
Solar and solc both compile Solidity, but they differ in focus. Solar emphasizes speed, low memory use and a modular, hackable design, and its published benchmarks compare it directly with solc's via-IR pipeline. solc remains the reference implementation of the language and is the compiler most tooling is built around.
If your main goal is to keep edit-compile-test cycles short, Solar is worth evaluating. If you need the exact behavior of the reference compiler across every edge case, keep solc in your toolchain and compare outputs. For editing and debugging, the tools listed in the related section, such as Remix Desktop or Visual Studio Code with a Solidity extension, can sit on top of whichever compiler you choose.
Specifications
- Price
- Free
- Type
- Open source
- License
- Apache-2.0|MIT
- Latest version
- 0.2.0
- Last update
- 30 Oct 2026
- Windows support
- Yes (available via Scoop)
- Source code
- github.com/paradigmxyz/solar
- Install command
- scoop install solar-compiler
Frequently asked questions
Yes. Solar Compiler is free and open source, released under the Apache-2.0 or MIT license. You can use it in personal and commercial projects, subject to the terms of the license you choose.
The easiest way is to run scoop install solar-compiler in PowerShell after installing Scoop. You can also download a pre-built Windows binary from the GitHub Releases page and add it to your PATH manually.
According to the project's benchmarks, Solar was about 100 times faster on average than solc's via-IR pipeline across six real-world projects, with up to 159 times faster on Morpho Blue. Results depend on your code and settings, so measure on your own project.
The project states that it is compatible with the latest Solidity language breaking version in the 0.8 series. Check the release notes for the version you install to confirm which language features are supported.
It is open source, so the code can be reviewed. Download it only from the official GitHub Releases page or Scoop, and verify checksums or signatures when available. Test any compiled contract thoroughly before deploying it to a live network.
Yes, its architecture is library-based. If you depend on it from Rust code, pin the version with the = operator, because the minimum supported Rust version may be updated at any time.
Foundry is a broader toolkit that includes a compiler, testing framework and local node. Solar focuses on compilation speed and a modular design, so it can complement a toolkit like Foundry rather than replace it entirely.
Verdict
Solar Compiler is a strong choice for Solidity developers who feel that compile times slow them down, especially on large projects. It is free, open source and easy to install on Windows through Scoop. Contributors who enjoy Rust will also find its modular code approachable. Before adopting it in a production workflow, benchmark it on your own contracts and check the latest release on the official GitHub page.