diff --git a/Cargo.toml b/Cargo.toml
index 5b2dece..f6221dc 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -14,10 +14,9 @@ exclude = ["images/", "tests/", "miette-derive/"]
 
 [dependencies]
 miette-derive = { path = "miette-derive", version = "=7.6.0", optional = true }
-unicode-width = { version = "0.2.0", default-features = false }
+unicode-width = "0.2.0"
 cfg-if = "1.0.0"
-# spin is needed for no_std environments (provides Once without std)
-spin = { version = "0.9", default-features = false, features = ["once"] }
+spin = { version = "0.9", default-features = false, features = ["once"], optional = true }
 
 owo-colors = { version = "4.0.0", optional = true }
 textwrap = { version = "0.16.0", default-features = false, features = ["unicode-linebreak", "unicode-width"], optional = true }
diff --git a/src/eyreish/mod.rs b/src/eyreish/mod.rs
index 3667b73..c7fb697 100644
--- a/src/eyreish/mod.rs
+++ b/src/eyreish/mod.rs
@@ -68,7 +68,7 @@ pub type ErrorHook =
 #[cfg(feature = "std")]
 static HOOK: OnceLock<ErrorHook> = OnceLock::new();
 
-#[cfg(not(feature = "std"))]
+#[cfg(all(not(feature = "std"), feature = "spin"))]
 static HOOK: spin::Once<ErrorHook> = spin::Once::new();
 
 fn default_hook() -> ErrorHook {
@@ -96,7 +96,7 @@ pub fn set_hook(hook: ErrorHook) -> Result<(), InstallError> {
 }
 
 /// Set the error hook.
-#[cfg(not(feature = "std"))]
+#[cfg(all(not(feature = "std"), feature = "spin"))]
 pub fn set_hook(hook: ErrorHook) -> Result<(), InstallError> {
     HOOK.call_once(|| hook);
     Ok(())
@@ -108,7 +108,7 @@ pub(crate) fn capture_handler(error: &(dyn Diagnostic + 'static)) -> Box<dyn Rep
     hook(error)
 }
 
-#[cfg(not(feature = "std"))]
+#[cfg(all(not(feature = "std"), feature = "spin"))]
 pub(crate) fn capture_handler(error: &(dyn Diagnostic + 'static)) -> Box<dyn ReportHandler> {
     let hook = HOOK.call_once(default_hook);
     hook(error)
@@ -126,7 +126,7 @@ pub(crate) fn capture_handler_with_location(
 }
 
 #[track_caller]
-#[cfg(not(feature = "std"))]
+#[cfg(all(not(feature = "std"), feature = "spin"))]
 pub(crate) fn capture_handler_with_location(
     error: &(dyn Diagnostic + 'static),
 ) -> Box<dyn ReportHandler> {