diff --git a/Cargo.lock b/Cargo.lock
index c9f42ce25292e..ed33db0f68801 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -863,6 +863,7 @@ dependencies = [
  "serde",
  "serde_json",
  "sha2",
+ "static_assertions",
  "thiserror",
  "url",
 ]
@@ -3458,6 +3459,12 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "static_assertions"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a2eb9349b6444b326872e140eb1cf5e7c522154d69e7a0ffb0fb81c06b37543f"
+
 [[package]]
 name = "strsim"
 version = "0.10.0"
diff --git a/Cargo.toml b/Cargo.toml
index 2492f13007f4d..c3d3d1c4197cf 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -74,6 +74,7 @@ seahash = { version = "4.1.0" }
 serde = { version = "1.0.194" }
 serde_json = { version = "1.0.111" }
 sha2 = { version = "0.10.8" }
+static_assertions = { version = "1.1.0" }
 tar = { version = "0.4.40" }
 target-lexicon = { version = "0.12.13" }
 tempfile = { version = "3.9.0" }
diff --git a/crates/distribution-types/Cargo.toml b/crates/distribution-types/Cargo.toml
index 4b87d2665d82e..bc89cbd66ca4f 100644
--- a/crates/distribution-types/Cargo.toml
+++ b/crates/distribution-types/Cargo.toml
@@ -32,5 +32,6 @@ rustc-hash = { workspace = true }
 serde = { workspace = true, features = ["derive"] }
 serde_json = { workspace = true }
 sha2 = { workspace = true }
+static_assertions = { workspace = true }
 thiserror = { workspace = true }
 url = { workspace = true }
diff --git a/crates/distribution-types/src/lib.rs b/crates/distribution-types/src/lib.rs
index 5a487807feecf..342cd1a98a3a6 100644
--- a/crates/distribution-types/src/lib.rs
+++ b/crates/distribution-types/src/lib.rs
@@ -37,6 +37,7 @@ use std::path::{Path, PathBuf};
 use std::str::FromStr;
 
 use anyhow::Result;
+use static_assertions::assert_eq_size;
 use url::Url;
 
 use distribution_filename::{DistFilename, SourceDistFilename, WheelFilename};
@@ -147,7 +148,7 @@ pub enum SourceDist {
 #[derive(Debug, Clone)]
 pub struct RegistryBuiltDist {
     pub filename: WheelFilename,
-    pub file: File,
+    pub file: Box<File>,
     pub index: IndexUrl,
 }
 
@@ -172,7 +173,7 @@ pub struct PathBuiltDist {
 #[derive(Debug, Clone)]
 pub struct RegistrySourceDist {
     pub filename: SourceDistFilename,
-    pub file: File,
+    pub file: Box<File>,
     pub index: IndexUrl,
 }
 
@@ -201,6 +202,10 @@ pub struct PathSourceDist {
     pub editable: bool,
 }
 
+assert_eq_size!(Dist, [u8; 240]);
+assert_eq_size!(BuiltDist, [u8; 240]);
+assert_eq_size!(SourceDist, [u8; 168]);
+
 impl Dist {
     /// Create a [`Dist`] for a registry-based distribution.
     pub fn from_registry(filename: DistFilename, file: File, index: IndexUrl) -> Self {
@@ -208,14 +213,14 @@ impl Dist {
             DistFilename::WheelFilename(filename) => {
                 Self::Built(BuiltDist::Registry(RegistryBuiltDist {
                     filename,
-                    file,
+                    file: Box::new(file),
                     index,
                 }))
             }
             DistFilename::SourceDistFilename(filename) => {
                 Self::Source(SourceDist::Registry(RegistrySourceDist {
                     filename,
-                    file,
+                    file: Box::new(file),
                     index,
                 }))
             }
diff --git a/crates/puffin-client/src/flat_index.rs b/crates/puffin-client/src/flat_index.rs
index 732fd2f8501ae..120951e8cf075 100644
--- a/crates/puffin-client/src/flat_index.rs
+++ b/crates/puffin-client/src/flat_index.rs
@@ -221,7 +221,7 @@ impl FlatIndex {
 
                 let dist = Dist::Built(BuiltDist::Registry(RegistryBuiltDist {
                     filename,
-                    file,
+                    file: Box::new(file),
                     index,
                 }));
                 match distributions.0.entry(version) {
@@ -238,7 +238,7 @@ impl FlatIndex {
             DistFilename::SourceDistFilename(filename) => {
                 let dist = Dist::Source(SourceDist::Registry(RegistrySourceDist {
                     filename: filename.clone(),
-                    file,
+                    file: Box::new(file),
                     index,
                 }));
                 match distributions.0.entry(filename.version.clone()) {