Build a CLI tool in Rust

What you end up with: hit, a command-line HTTP client you would actually use — subcommands, request headers and bodies, a config file, coloured and JSON output, and a release build you can hand to someone else.

Command-line tools are where most people write their first real Rust, and for good reason: no async runtime to fight with at the start, no framework abstractions, and the feedback loop is a single cargo run. By the end of the track you will have used half the crates that show up in every Rust CLI: clap, reqwest, serde, anyhow, indicatif.

What you’ll build

• hit get https://example.com — send a request, print a readable response
• Subcommands (get, post, header) modelled as Rust enums
• --json output for piping into jq
• A ~/.config/hit/config.toml file with environment-variable overrides
• Tests: unit tests, integration tests, and snapshot tests for output
• A signed, cross-compiled release binary and a Homebrew formula

Before you start

You need Rust installed (rustup.rs if it is not) and a rough idea of what ownership does. If either is shaky, start here:

• Cargo and project layout — crates, modules, dependencies, and where everything lives
• Ownership and borrowing — reading the first four articles is enough
• Option, Result, and error handling — ?, Result, and when unwrap() is fine

No async experience required — the track introduces it where it is actually needed.

Articles

• What we’re building: hit, a command-line HTTP clientthe finished tool, then the route to it
• Setting up a Rust CLI projectcargo new, layout, and the first dependency
• Parsing command-line arguments with clapderive, subcommands, and repeatable flags
• Making a real HTTP request with reqweststatus, headers, body, and a timeout that works
• Handling errors without panickinga custom error type and messages worth reading
• Colour, tables, and readable outputstatus-code colours and headers as a table
• Showing progress for slow requestsa spinner that appears only when it should
• Reading defaults from a config file~/.hit.toml with serde and directories
• Saving and reusing requestshit save and hit run, stored as JSON
• Making it fast: async with tokioconcurrent requests and joining the results
• Testing a CLI without a networkassert_cmd plus a mock server in CI
• Shipping it: release builds and installersrelease profile, stripping, multi-platform binaries

Where the code lives

cli-tool/ in the examples repository — each article links to the tag that matches its finished state.