docs.rs: building fewer targets by default | Rust Blog

Building fewer targets by default

On 2026-05-01, docs.rs will make a breaking change to its build behavior.

Today, if a crate does not define a targets list in its docs.rs metadata, docs.rs builds documentation for a default list of five targets.

Starting on 2026-05-01, docs.rs will instead build documentation for only the default target unless additional targets are requested explicitly.

This is the next step in a change we first introduced in 2020, when docs.rs added support for opting into fewer build targets. Most crates do not compile different code for different targets, so building fewer targets by default is a better fit for most releases. It also reduces build times and saves resources on docs.rs.

This change only affects:

1. new releases
2. rebuilds of old releases

How is the default target chosen?

If you do not set default-target, docs.rs uses the target of its build servers: x86_64-unknown-linux-gnu.

You can override that by setting default-target in your docs.rs metadata:

[package.metadata.docs.rs]
default-target = "x86_64-apple-darwin"

How do I build documentation for additional targets?

If your crate needs documentation to be built for more than the default target, define the full list explicitly in your Cargo.toml:

[package.metadata.docs.rs]
targets = [
    "x86_64-unknown-linux-gnu",
    "x86_64-apple-darwin",
    "x86_64-pc-windows-msvc",
    "i686-unknown-linux-gnu",
    "i686-pc-windows-msvc"
]

When targets is set, docs.rs will build documentation for exactly those targets.

docs.rs still supports any target available in the Rust toolchain. Only the default behavior is changing.