cargo-metadata
Retrieve Rust crate metadata in JSON format
TLDR
Print the workspace members and resolved dependencies of the current package
Print only the workspace members and do not fetch dependencies
Print metadata in a specific format based on the specified version
Print metadata with the resolve field including dependencies only for the given target triple (Note: The packages array will still include the dependencies for all targets)
SYNOPSIS
cargo metadata [--format-version VERSION] [--filter-platform TRIPLE] [--all-features] [--no-deps] [--features FEATURES] [-p SPEC...] [--manifest-path PATH]
PARAMETERS
--format-version VERSION
JSON format version (default: 1, only 1 supported)
--filter-platform TRIPLE
Filter dependencies to given platform triple (e.g., x86_64-unknown-linux-gnu)
--all-features
Activate all features of all dependencies
--no-deps
Exclude resolved dependencies (direct deps only)
--features FEATURES
Comma/space-separated features to activate
-p, --package SPEC
Restrict to specific package(s) by name/version
--manifest-path PATH
Path to Cargo.toml (common Cargo option)
DESCRIPTION
cargo metadata is a Cargo subcommand that emits a structured JSON document describing the current workspace or package, including resolved dependencies, features, packages, targets, and more. It serves as a stable, machine-readable interface for tools like IDEs (e.g., rust-analyzer), CI systems, and scripts to query project structure without parsing Cargo.toml manually.
The output includes keys like packages (array of package objects with name, version, features), workspace_members, resolve (dependency graph), target_directory, and version (format version, default 1).
Common use cases: generating dependency graphs, listing transitive deps, or integrating with external build tools. By default, it resolves the workspace; options allow filtering to specific packages, platforms, or feature sets. Output is deterministic for reproducible tooling.
Designed for stability, format version 1 has been unchanged since introduction, ensuring backward compatibility.
CAVEATS
Output can be very large (>1MB) for complex workspaces; pipe to jq for filtering. Requires Cargo workspace or package context.
JSON OUTPUT KEYS
Core fields: packages (all pkgs), workspace_members (member IDs), resolve (nodes/edges graph), target_directory, workspace_root.
HISTORY
Introduced in Cargo 0.18 (2017); stable JSON format 1 since 0.20 (2018). Widely used in Rust tooling ecosystem.
