Forge

Forge compiles, tests, and deploys Solidity smart contracts. It's the core development tool in the Foundry suite.

Core workflows

Build and test

Compile contracts and run tests with traces.

Advanced testing

Fuzz, invariant, and fork-based testing workflows.

Deploy and verify

Ship contracts with scripts and verify on explorers.

Debug and optimize

Trace failures and track gas usage.

Key capabilities

Feature	Description
Compilation	Compile contracts with configurable Solidity versions and optimization
Testing	Write tests in Solidity with fuzzing, forking, and gas reporting
Scripting	Deploy and interact with contracts using Solidity scripts
Verification	Verify source code on Etherscan and other explorers
Analysis	Inspect bytecode, storage layouts, and gas usage

Common workflows

Build your project

$ forge build

Solc 0.8.33 finished in 1.07s
Compiler run successful!

Run all tests

$ forge test

Compiling...
No files changed, compilation skipped
Ran 2 tests for test/Counter.t.sol:CounterTest
[PASS] testFuzz_SetNumber(uint256) (runs: 256, μ: 26879, ~: 29289)
[PASS] test_Increment() (gas: 28783)
Suite result: ok. 2 passed; 0 failed; 0 skipped; finished in 5.39ms (5.16ms CPU time)
Ran 1 test suite in 9.40ms (5.39ms CPU time): 2 tests passed, 0 failed, 0 skipped (2 total tests)

Run tests with verbose output

$ forge test -vvvv

Compiling...
No files changed, compilation skipped
Ran 1 test for test/OwnerUpOnly.t.sol:OwnerUpOnlyTest
[PASS] test_IncrementAsOwner() (gas: 29808)
Traces:
  [29808] OwnerUpOnlyTest::test_IncrementAsOwner()
    ├─ [2407] OwnerUpOnly::count() [staticcall]
    │   └─ ← [Return] 0
    ├─ [20460] OwnerUpOnly::increment()
    │   └─ ← [Stop]
    ├─ [407] OwnerUpOnly::count() [staticcall]
    │   └─ ← [Return] 1
    └─ ← [Stop]
Suite result: ok. 1 passed; 0 failed; 0 skipped; finished in 288.76µs (54.88µs CPU time)
Ran 1 test suite in 7.73ms (288.76µs CPU time): 1 tests passed, 0 failed, 0 skipped (1 total tests)

Deploy via script

$ forge script script/Deploy.s.sol --broadcast --rpc-url $RPC_URL

Verify a deployed contract

$ forge verify-contract $ADDRESS src/Counter.sol:Counter --etherscan-api-key $KEY

Learn more

Building contracts — Compilation, artifacts, and optimization
Testing — Writing and running tests
Scripting — Deployment and on-chain interactions
Debugging — Traces, debugger, and troubleshooting
Gas tracking — Snapshots and reports
Linting — Code style enforcement
Reference — Full CLI reference

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