Ditch Prettier for `forge fmt` in VS Code with one setting

Prettier works fine for Solidity. It just doesn't know what's in your foundry.toml.

If you're using Foundry, your project already has a [fmt] block that controls line length, quote style, import sorting, and eight other formatting rules. Running Prettier in parallel means maintaining two separate configs — and watching them silently disagree every time you save a file.

The Solidity by Nomic Foundation extension (NomicFoundation.hardhat-solidity) v0.8.29 has a formatter switch that routes all .sol formatting through forge fmt instead. 1 One config key, and VS Code's "Format Document" shortcut starts calling forge fmt using exactly the rules in your foundry.toml.

The fix: `"solidity.formatter": "forge"`

Open your VS Code settings JSON (Ctrl+Shift+P → Preferences: Open User Settings (JSON), or Cmd+Shift+P on macOS) and add:

"solidity.formatter": "forge"

The extension supports three values for this key: "prettier" (the default), "forge", and "none". 2 Setting it to "forge" makes every Save+Format or Shift+Alt+F call run forge fmt on the current file in-place.

If you have other Solidity extensions installed alongside this one (JuanBlanco.solidity is common), add a second line to make the Nomic Foundation extension the explicit default:

"solidity.formatter": "forge",
"[solidity]": {
  "editor.defaultFormatter": "NomicFoundation.hardhat-solidity"
}

That's the entire setup. No separate formatter config file, no .prettierrc for Solidity, no extension conflict. forge fmt reads foundry.toml and formats accordingly.

VS Code right-click context menu showing "Format Document With..." option for a Solidity file — VS Code formatter picker for `.sol` files — after setting `"solidity.formatter": "forge"`, the Nomic Foundation extension handles all formatting calls. 1

What `[fmt]` controls

Once forge is the formatter backend, all rules come from your project's foundry.toml. The [fmt] section supports 10 options: 3

Option	Default	What it does
`line_length`	`120`	Max characters per line before wrapping
`tab_width`	`4`	Spaces per indentation level
`bracket_spacing`	`false`	Space inside `{` and `}` in expression contexts
`quote_style`	`"double"`	`"single"` or `"double"` for string literals
`sort_imports`	`false`	Alphabetically sort `import` statements
`multiline_func_header`	`"attributes_first"`	How to break long function signatures
`number_underscore`	`"preserve"`	Underscore placement in numeric literals
`single_line_statement_blocks`	`"preserve"`	Collapse `if (x) { y; }` to one line or not
`wrap_comments`	`false`	Reflow `//` comment text to fit `line_length`
`ignore`	`[]`	Glob patterns for files to skip formatting

A minimal foundry.toml that sets tighter defaults than Foundry ships with:

[profile.default]
src = "src"
out = "out"
libs = ["lib"]
solc_version = "0.8.28"
remappings = [
  "@openzeppelin/=lib/openzeppelin-contracts/"
]

[fmt]
line_length = 80
tab_width = 2
bracket_spacing = true
quote_style = "single"
sort_imports = true

Change any value, save the file, and the next "Format Document" call picks up the new rule immediately — no VS Code restart needed.

The Foundry project detection flow

The extension activates automatically when it finds a foundry.toml anywhere in the workspace. 2 Once active, the VS Code status bar shows a "Solidity" section with the project type — click it to open the config file directly.

VS Code status bar animation showing Foundry project detection and config file path — Status bar showing detected project type and config file path — click to open `foundry.toml`. 1

Beyond formatting, the detection phase gives the extension two more pieces of information it uses for language features:

Compiler version — read from solc_version in [profile.default], used to run the correct solc binary for inline diagnostics (the red squiggles)
Remappings — read from the remappings array in foundry.toml or from remappings.txt, used to resolve import paths for go-to-definition and autocomplete 4

A full workflow from `forge init` to formatted contract

If you're starting from scratch:

Install Foundry: curl -L https://foundry.paradigm.xyz | bash && foundryup 5
Create the project: forge init my-project && cd my-project
Open in VS Code: code . — the extension detects foundry.toml on first load
Add "solidity.formatter": "forge" to VS Code settings JSON
Open src/Counter.sol, press Shift+Alt+F — forge fmt runs and formats the file

At step 3, open the Problems panel. If VS Code shows "Validation blocked — No available solc version satisfying...", run forge build once in the terminal. That populates the compiler cache and clears the error. 6 This only affects brand-new projects before the first build; existing projects with a populated cache don't hit it.

What's still experimental (be honest about this)

Foundry support is explicitly labeled experimental in the extension's marketplace page. 1 That label has real meaning — a few capabilities that work seamlessly in Hardhat projects don't work in Foundry yet:

Inline validation and quickfixes are Hardhat-only. The red squiggles appear, but the one-click "fix" code actions (implement interface stubs, add virtual/override, fix visibility) only activate for Hardhat projects. The README states this is "a limitation that will be lifted with future releases." 7
No Foundry equivalents for Hardhat commands. "Hardhat: Compile project", "Hardhat: Clear cache and artifacts", and "Hardhat: Flatten this file" appear in the Command Palette only when a Hardhat project is open. 7

There are also 8 open Foundry-related bugs on GitHub. 8 Two are worth knowing about before you commit to this setup:

#722 (P0, open) — In Foundry monorepos where sub-projects have their own node_modules, the extension scans those nested directories and can freeze VS Code or Cursor entirely. The root node_modules is correctly excluded, but nested ones aren't. 9 v0.8.27 fixed the case where Foundry projects sat inside node_modules, but the inverse (monorepo with nested node_modules) remains open.
#712 (open) — If a workspace contains both a foundry.toml and a Hardhat config file, go-to-definition and autocomplete break for some imports. 8

For a solo Foundry project or a monorepo without nested node_modules, the formatting and navigation features work reliably. If you're running a complex monorepo that mixes Hardhat and Foundry sub-projects in the same workspace, hold off.

Install

github.com · GitHub repository

NomicFoundation/hardhat-vscode

https://github.com/NomicFoundation/hardhat-vscode

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Plugin: Solidity by Nomic Foundation · Publisher: Nomic Foundation (verified) · Version: v0.8.29 1 Languages: Solidity · IDE: VS Code ≥ 1.99.0 · License: MIT · Installs: 421,520 · Rating: 4.4/5 Use case: Solidity language support + Foundry integration (forge fmt, foundry.toml detection, remappings) Install: NomicFoundation.hardhat-solidity on VS Code Marketplace · GitHub

Ditch Prettier for `forge fmt` in VS Code with one setting

The fix: "solidity.formatter": "forge"

What [fmt] controls