Blanc is an open-source toolchain for developers who write blockchain contracts that compile to WebAssembly. It targets EOSIO and, in an experimental form, CosmWasm. The project is deprecated and its last code update dates to October 2023, so treat it as a tool for maintaining existing code, learning how contract builds work, or studying the approach rather than starting a new production project.
The program is free and released under the MIT license, which lets you read, modify and reuse the code. Its listed platforms are macOS and Linux. The project suggests it can build for Windows, but that support is unconfirmed, so check the GitHub Releases page before planning a Windows workflow. The most recent version recorded is 16.0.0.
What Is a WebAssembly Contract Toolchain?
WebAssembly, usually shortened to Wasm, is a compact binary format designed to run code quickly and predictably across environments. Blockchain platforms use it to execute smart contracts, which are programs that run on a chain and manage shared state. A contract written in a source language must be compiled into a Wasm module before the chain can run it.
A toolchain is the set of compilers, linkers and helper scripts that carry that process from source file to deployable artifact. The toolchain decides how contracts are compiled, which libraries they link against and what the final module contains. Developers who maintain several contracts often value a consistent toolchain more than any single feature, because it keeps builds reproducible.
Blanc fits this role. It focuses on the build step for WebAssembly contracts targeting EOSIO and CosmWasm, rather than on editing, deployment or wallet functions. Thinking of it as a build stage in a larger pipeline helps set realistic expectations.
Who Blanc Is For
Blanc is most relevant to developers who already write contracts for EOSIO and need to keep an existing codebase building. A team that inherits a Wasm contract project may use it to understand the build pipeline, reproduce outputs or patch a build script.
Researchers and students also benefit. Because the code is MIT-licensed and written in C and C++, it can be read as a case study in how a contract toolchain is put together. Reading a small, focused build tool often teaches more about compilation and linking than reading a large framework.
Blanc is less suited to someone who wants a guided environment with a graphical editor, built-in testing and frequent updates. For a new project, that person should look at actively maintained tools in the same category.
Working Safely With Deprecated Blockchain Tools
A deprecated project still works until the environment around it changes. Chains release new versions, compilers change behavior and operating systems drop old libraries. When the last code update is more than two years old, expect breakage as those changes accumulate.
A practical approach is to pin everything: the Blanc release, the compiler versions and the chain tooling your contract targets. Store those versions in your project notes so you can rebuild the same output later. Keep a copy of the working build environment, including checksums of the Blanc files you used.
If you intend to keep the contract in service, plan a migration path early. Test the contract's behavior on a local development node after every change, and keep the migration effort separate from regular feature work so that neither is rushed.
Key features
WebAssembly contract builds
EOSIO and CosmWasm targets
Open C and C++ codebase
Supported coins
Blanc covers two blockchain ecosystems: EOSIO and CosmWasm. EOSIO support is the core target of the toolchain, while CosmWasm support is labeled experimental, so it suits prototypes more than production launches. Contracts built for either chain still need their own deployment and testing steps outside this toolchain.
How to install Blanc on Windows
- 1
Get the source or release
Open the project's GitHub Releases page at github.com/haderech/blanc, or follow the link from the official project site. Choose the most recent release listed, which is 16.0.0 at the time of writing. Download only from the official website or the GitHub repository, and avoid copies on unrelated download sites.
- 2
Verify the download
Compare the SHA-256 checksum of the file with the value published on the release page, or check the signature if one is provided. If the values do not match, stop and download the file again from the source before continuing.
-
Build or install for your platform
Because the listed platforms are macOS and Linux, the most predictable path is to build from source on a Linux machine, following the repository's instructions. Windows builds are reported but not confirmed, so treat any Windows attempt as a trial and test the output carefully before relying on it.
System requirements
- Listed platforms: macOS and Linux
- Windows builds are reported by the project but not confirmed
How to use Blanc
Blanc is a build tool, so the workflow centers on a project folder and a compile step. The sequence below reflects how most contract toolchains work. Follow the repository's own README for exact commands, since they may change between releases.
- Create a project folder for your contract source and keep it under version control.
- Pin the Blanc release you tested, such as 16.0.0, so builds stay reproducible.
- Write or copy your contract code in the language the target chain expects.
- Run the build step described in the repository to produce the WebAssembly output.
- Inspect the generated module and confirm its size and exports match what you expect.
- Test the output on a local development node before any public deployment.
- Record the build environment, including operating system and compiler versions, in your project notes.
Keeping these notes makes it far easier to rebuild the same module months later, which matters for a tool that no longer receives updates.
Pros & cons
- Free and MIT-licensed, so the code is open to inspection and modification
- Targets WebAssembly contracts for EOSIO and CosmWasm in one toolchain
- Written in C and C++, which suits developers comfortable with native build chains
- Public source on GitHub makes the build logic easy to read
- Deprecated, with the last code update in October 2023
- Windows support is unconfirmed; macOS and Linux are the listed platforms
- CosmWasm support is experimental
- Without ongoing maintenance, fixes for newer chain versions may never arrive
Is Blanc safe?
Blanc is deprecated and has not seen code updates since October 2023, so treat it as a security risk surface rather than a maintained product. Download only from the official website or the GitHub repository at github.com/haderech/blanc, and avoid copies on third-party sites. Verify the SHA-256 checksum or signature of any archive before running it. Review generated code for anything unexpected, and never paste seed phrases or private keys into build scripts, test files or third-party websites. If a contract will control real assets, have it reviewed by someone independent before deployment.
- Official source only. Download from github.com/haderech/blanc. 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
Foundry and Solidity cover Ethereum-style contracts, with Foundry offering a full development kit and Solidity providing the compiler itself. Anchor targets Solana programs, so it serves a different chain entirely. Blanc is narrower than all three: a WebAssembly build toolchain for EOSIO and CosmWasm. Remix Desktop suits developers who want an interactive editor, while Blanc is a build-focused tool with no editor. The biggest difference is maintenance status. For a new project, choose an actively maintained tool for your target chain, since Blanc's last code update was in October 2023.
Specifications
- Price
- Free
- Type
- Open source
- License
- MIT
- Latest version
- 16.0.0
- Last update
- 5 Oct 2023
- Windows support
- Likely (builds for Windows; check releases)
- Source code
- github.com/haderech/blanc
Frequently asked questions
Blanc's listed platforms are macOS and Linux, and Windows support is unconfirmed. The project indicates it can build for Windows, so check the GitHub Releases page for current notes before you try it. If you need a dependable setup, a Linux machine or virtual machine is the safer route. Test any build output before relying on it.
No. Blanc is marked deprecated, and its last code update was in October 2023. You can still read the source and use existing releases, but do not expect fixes for newer chain versions. If your project depends on it long term, plan a migration early.
Yes. Blanc is free and released under the MIT license. The license allows you to use, copy, modify and redistribute the code, as long as the license notice is kept. Free use does not mean active support, so weigh that when choosing it for a project.
Blanc supports EOSIO and CosmWasm, with CosmWasm support labeled experimental. It builds WebAssembly-based contracts for those networks. It is not a blockchain node or wallet, so you will still need separate tools to deploy and interact with contracts.
The code is open source, so you can inspect it, which helps. However, the project is deprecated, so security fixes may be missing. Obtain the software from the project's own repository, check the checksum before running it, and review any output that will handle real assets.
For Ethereum-style contracts, Foundry and Solidity are natural choices, and Remix Desktop suits an interactive IDE workflow. For Solana, Anchor is the framework to compare. Pick a tool based on the chain you target rather than popularity alone.
Verdict
Blanc suits developers who already work with EOSIO, or who must maintain WebAssembly contracts built with it, and researchers who want to study a small MIT-licensed toolchain. It is a poor fit for new production projects because it is deprecated, its last code update was in October 2023, and Windows support is unconfirmed. If you proceed, pin a tested version, verify every download and test thoroughly. Check the latest version on the official website before making any decision.