Blended Counter

This example demonstrates how to build, test, and deploy a blended Solidity + Rust (WASM) smart contract using Gblend — a Foundry-compatible CLI for the Fluent network.

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Project Structure

src/
├── BlendedCounter.sol        # Main Solidity contract
└── power-calculator/         # Rust WASM module for power calculations
test/                         # Solidity tests
script/                       # Deployment scripts
foundry.toml                  # Project configuration

How it works:

• The Solidity contract BlendedCounter.sol interacts with a Rust module compiled to WASM.
• The Rust module (power-calculator/) implements computation logic using fluentbase-sdk.
• Gblend builds, tests, and deploys both Solidity and Rust components in a single unified workflow.

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1. Project Setup

Create a new blended project:

gblend init my-blended-app
cd my-blended-app

VS Code Configuration (optional)

To enable Rust Analyzer and Solidity support, create .vscode/settings.json:

{
  "rust-analyzer.linkedProjects": [
    "src/power-calculator/Cargo.toml"
  ],
  "rust-analyzer.cargo.target": "wasm32-unknown-unknown",
  "files.watcherExclude": {
    "**/target/**": true,
    "**/out/**": true
  },
  "solidity.packageDefaultDependenciesDirectory": "lib",
  "solidity.packageDefaultDependenciesContractsDirectory": ""
}

Make sure you have the wasm32 target installed:

rustup target add wasm32-unknown-unknown

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2. Build

gblend build

Compiles both Solidity and Rust (WASM) contracts and generates artifacts in the out/ directory. The first build may take longer as the Fluent build image is downloaded for reproducible builds.

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3. Test

gblend test -v

Runs all tests in a shared Fluent-compatible runtime. Both Solidity and Rust contracts execute in the same environment — identical to the runtime used by Fluent nodes on-chain.

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4. Deploy

Use the provided Forge-style script to deploy both contracts:

gblend script script/Deploy.s.sol \
  --private-key $PK \
  --rpc-url https://rpc.devnet.fluent.xyz \
  --broadcast

This script:

• Deploys the Rust PowerCalculator (compiled to WASM)
• Deploys the Solidity BlendedCounter
• Links them together on-chain

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5. Verify

Contracts can be verified separately on Blockscout.

Rust (WASM) Contract

gblend verify-contract <POWER_CALCULATOR_ADDRESS> power-calculator.wasm \
  --rpc-url https://rpc.devnet.fluent.xyz \
  --wasm \
  --verifier blockscout \
  --verifier-url https://devnet.fluentscan.xyz/api/

Solidity Contract

gblend verify-contract <BLENDED_COUNTER_ADDRESS> BlendedCounter \
  --rpc-url https://rpc.devnet.fluent.xyz \
  --verifier blockscout \
  --verifier-url https://devnet.fluentscan.xyz/api/

Verification for WASM contracts may take several minutes.

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6. Alternative: Direct Deployment

You can also deploy a single compiled WASM contract directly:

gblend create power-calculator.wasm \
  --rpc-url https://rpc.devnet.fluent.xyz \
  --private-key $PK \
  --broadcast \
  --verify \
  --wasm \
  --verifier blockscout \
  --verifier-url https://devnet.fluentscan.xyz/api/

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References

• Gblend Installation Guide
• Fluent Overview
• Foundry Book