crates.io Sparse Index
The crates.io sparse index at https://index.crates.io serves the registry config document plus per-crate newline-delimited JSON metadata files over HTTP, replacing the legacy git index clone. Cargo uses the sparse protocol by default since Rust 1.70 (June 2023). Each index entry records a version's dependencies, features, SHA-256 checksum, and yank state.
crates.io Sparse Index is one of 2 APIs that crates.io publishes on the APIs.io network, described by a machine-readable OpenAPI specification.
This API exposes 1 machine-runnable capability that can be deployed as REST, MCP, or Agent Skill surfaces via Naftiko and 1 JSON Schema definition.
Tagged areas include Index, Package Registry, Rust, and Sparse Protocol. The published artifact set on APIs.io includes API documentation, an OpenAPI specification, sample payloads, 1 Naftiko capability spec, and 1 JSON Schema.