Rust Code Formatter & Beautifier

A Rust function with nested match expressions, chained Result handling with ? operators, and complex generic bounds spanning multiple lines. The ownership and lifetime annotations make dense Rust code especially hard to read without consistent formatting.

What Is a Rust Formatter?

A Rust formatter takes Rust source code and restructures it according to the official Rust style guide — the same rules enforced by rustfmt. It normalizes indentation, aligns match arms, formats generic bounds, organizes use declarations, and ensures consistent spacing throughout. Whether you’re working on systems code, web services with Actix/Axum, or CLI tools with Clap, a formatter makes Rust’s dense syntax readable.

This tool supports:

• 4-space indentation — the Rust standard
• Match arm alignment — consistent formatting for pattern matching
• Generic bounds formatting — proper line breaks for complex where clauses
• Use declaration grouping — organized imports by crate origin

Rust Formatting Conventions

Rust has an official style guide enforced by rustfmt, and the community follows it almost universally:

• 4 spaces for indentation — never tabs
• Opening brace on the same line as the function, struct, enum, or control statement
• where clauses on separate lines when generic bounds exceed the line width
• Match arms indented one level, with => aligned where practical
• Trailing commas in struct literals, enum variants, function parameters, and match arms
• use declarations grouped: std first, then external crates, then local modules
• Line length of 100 characters — the rustfmt default

Common Use Cases

Open source contribution: Most Rust projects require rustfmt-formatted code. Format your contribution before submitting a PR to pass CI checks.

Code review: Rust’s ownership system and lifetime annotations make code dense. Consistent formatting lets reviewers focus on correctness and safety rather than style.

Learning Rust: Properly formatted Rust code makes ownership flows, borrowing patterns, and lifetime relationships visible through indentation and spacing.

Sharing code snippets: Format Rust code before posting it in forums, documentation, or blog posts for maximum readability.

Frequently Asked Questions

Does this handle async/await syntax? Yes. Async functions (async fn), .await expressions, async blocks, and async closures are formatted with proper indentation and spacing.

Can it format Rust macros? Declarative macros (macro_rules!) and macro invocations (vec![], println!()) are handled. Procedural macro definitions are formatted as regular Rust code.

Does it handle lifetime annotations? Yes. Lifetime parameters ('a, 'static), lifetime bounds (T: 'a), and complex generic signatures like fn foo<'a, 'b: 'a, T: Display + 'a>(x: &'a T) are formatted with proper spacing.

Is my Rust code sent to a server? No. All formatting runs entirely in your browser. No code is transmitted to any server. Your source code stays completely private.