diff --git a/Cargo.lock b/Cargo.lock
index fbf9112..acfeb15 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -85,6 +85,28 @@ version = "1.7.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8318a53db07bb3f8dca91a600466bdb3f2eaadeedfdbcf02e1accbad9271ba50"
 
+[[package]]
+name = "capacity_builder"
+version = "0.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8f2d24a6dcf0cd402a21b65d35340f3a49ff3475dc5fdac91d22d2733e6641c6"
+dependencies = [
+ "capacity_builder_macros",
+ "ecow",
+ "hipstr",
+ "itoa",
+]
+
+[[package]]
+name = "capacity_builder_macros"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3b4a6cae9efc04cc6cbb8faf338d2c497c165c83e74509cf4dbedea948bbf6e5"
+dependencies = [
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "cc"
 version = "1.1.12"
@@ -171,9 +193,9 @@ dependencies = [
 
 [[package]]
 name = "deno_lockfile"
-version = "0.23.2"
+version = "0.24.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "559c19feb00af0c34f0bd4a20e56e12463fafd5c5069d6005f3ce33008027eea"
+checksum = "632e835a53ed667d62fdd766c5780fe8361c831d3e3fbf1a760a0b7896657587"
 dependencies = [
  "deno_semver",
  "serde",
@@ -186,6 +208,7 @@ name = "deno_npm"
 version = "0.26.0"
 dependencies = [
  "async-trait",
+ "capacity_builder",
  "deno_error",
  "deno_lockfile",
  "deno_semver",
@@ -204,11 +227,14 @@ dependencies = [
 
 [[package]]
 name = "deno_semver"
-version = "0.6.0"
+version = "0.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4756be7351289726087408984db18b9eb5e0186907673f39f858d119d0162071"
+checksum = "a21aae482ce4a88e8a9f4746f4f93a3069709d297a7a5593bf984f221792d012"
 dependencies = [
+ "capacity_builder",
  "deno_error",
+ "ecow",
+ "hipstr",
  "monch",
  "once_cell",
  "serde",
@@ -258,6 +284,15 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "ecow"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e42fc0a93992b20c58b99e59d61eaf1635a25bfbe49e4275c34ba0aee98119ba"
+dependencies = [
+ "serde",
+]
+
 [[package]]
 name = "encoding_rs"
 version = "0.8.35"
@@ -456,6 +491,17 @@ version = "0.3.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d231dfb89cfffdbc30e7fc41579ed6066ad03abda9e567ccafae602b97ec5024"
 
+[[package]]
+name = "hipstr"
+version = "0.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "97971ffc85d4c98de12e2608e992a43f5294ebb625fdb045b27c731b64c4c6d6"
+dependencies = [
+ "serde",
+ "serde_bytes",
+ "sptr",
+]
+
 [[package]]
 name = "http"
 version = "1.2.0"
@@ -725,9 +771,9 @@ checksum = "ddc24109865250148c2e0f3d25d4f0f479571723792d3802153c60922a4fb708"
 
 [[package]]
 name = "itoa"
-version = "1.0.11"
+version = "1.0.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "49f1f14873335454500d59611f1cf4a4b0f786f9ac11f4312a78e4cf2566695b"
+checksum = "d75a2a4b1b190afb6f5425f10f6a8f959d2ea0b9c2b1d79553551850539e4674"
 
 [[package]]
 name = "js-sys"
@@ -1147,6 +1193,15 @@ dependencies = [
  "serde_derive",
 ]
 
+[[package]]
+name = "serde_bytes"
+version = "0.11.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "387cc504cb06bb40a96c8e04e951fe01854cf6bc921053c954e4a606d9675c6a"
+dependencies = [
+ "serde",
+]
+
 [[package]]
 name = "serde_derive"
 version = "1.0.208"
@@ -1229,6 +1284,12 @@ version = "0.9.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6980e8d7511241f8acf4aebddbb1ff938df5eebe98691418c4468d0b72a96a67"
 
+[[package]]
+name = "sptr"
+version = "0.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3b9b39299b249ad65f3b7e96443bad61c02ca5cd3589f46cb6d610a0fd6c0d6a"
+
 [[package]]
 name = "stable_deref_trait"
 version = "1.2.0"
diff --git a/Cargo.toml b/Cargo.toml
index 929b519..484415e 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -11,9 +11,9 @@ license = "MIT"
 
 [dependencies]
 async-trait = "0.1.68"
-deno_semver = "0.6.0"
+deno_semver = "0.7.0"
 deno_error = "0.5.2"
-deno_lockfile = "0.23.2"
+deno_lockfile = "0.24.0"
 monch = "0.5.0"
 log = "0.4"
 serde = { version = "1.0.130", features = ["derive", "rc"] }
@@ -21,6 +21,7 @@ serde_json = { version = "1.0.67", features = ["preserve_order"] }
 thiserror = "2.0.3"
 futures = "0.3.28"
 url = "2"
+capacity_builder = "0.5.0"
 
 [dev-dependencies]
 divan = "0.1.17"
diff --git a/src/lib.rs b/src/lib.rs
index f7ff217..130a802 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -4,13 +4,18 @@
 #![deny(clippy::print_stdout)]
 #![deny(clippy::unused_async)]
 
-use std::borrow::Cow;
 use std::cmp::Ordering;
 use std::collections::BTreeMap;
 use std::collections::HashMap;
 use std::collections::HashSet;
 
+use capacity_builder::CapacityDisplay;
+use capacity_builder::StringAppendable;
+use capacity_builder::StringBuilder;
 use deno_semver::package::PackageNv;
+use deno_semver::CowVec;
+use deno_semver::SmallStackString;
+use deno_semver::StackString;
 use deno_semver::Version;
 use registry::NpmPackageVersionBinEntry;
 use registry::NpmPackageVersionDistInfo;
@@ -30,12 +35,77 @@ pub struct NpmPackageIdDeserializationError {
   text: String,
 }
 
+#[derive(
+  Clone,
+  Default,
+  PartialEq,
+  Eq,
+  Hash,
+  Serialize,
+  Deserialize,
+  PartialOrd,
+  Ord,
+  CapacityDisplay,
+)]
+pub struct NpmPackageIdPeerDependencies(CowVec<NpmPackageId>);
+
+impl<const N: usize> From<[NpmPackageId; N]> for NpmPackageIdPeerDependencies {
+  fn from(value: [NpmPackageId; N]) -> Self {
+    Self(CowVec::from(value))
+  }
+}
+
+impl NpmPackageIdPeerDependencies {
+  pub fn with_capacity(capacity: usize) -> Self {
+    Self(CowVec::with_capacity(capacity))
+  }
+
+  pub fn as_serialized(&self) -> StackString {
+    capacity_builder::appendable_to_string(self)
+  }
+
+  pub fn push(&mut self, id: NpmPackageId) {
+    self.0.push(id);
+  }
+
+  pub fn iter(&self) -> impl Iterator<Item = &NpmPackageId> {
+    self.0.iter()
+  }
+
+  fn peer_serialized_with_level<'a, TString: capacity_builder::StringType>(
+    &'a self,
+    builder: &mut StringBuilder<'a, TString>,
+    level: usize,
+  ) {
+    for peer in &self.0 {
+      // unfortunately we can't do something like `_3` when
+      // this gets deep because npm package names can start
+      // with a number
+      for _ in 0..level + 1 {
+        builder.append('_');
+      }
+      peer.as_serialized_with_level(builder, level + 1);
+    }
+  }
+}
+
+impl<'a> StringAppendable<'a> for &'a NpmPackageIdPeerDependencies {
+  fn append_to_builder<TString: capacity_builder::StringType>(
+    self,
+    builder: &mut StringBuilder<'a, TString>,
+  ) {
+    self.peer_serialized_with_level(builder, 0)
+  }
+}
+
 /// A resolved unique identifier for an npm package. This contains
 /// the resolved name, version, and peer dependency resolution identifiers.
-#[derive(Clone, PartialEq, Eq, Hash, Serialize, Deserialize)]
+#[derive(
+  Clone, PartialEq, Eq, Hash, Serialize, Deserialize, CapacityDisplay,
+)]
 pub struct NpmPackageId {
   pub nv: PackageNv,
-  pub peer_dependencies: Vec<NpmPackageId>,
+  pub peer_dependencies: NpmPackageIdPeerDependencies,
 }
 
 // Custom debug implementation for more concise test output
@@ -46,38 +116,26 @@ impl std::fmt::Debug for NpmPackageId {
 }
 
 impl NpmPackageId {
-  pub fn as_serialized(&self) -> String {
-    self.as_serialized_with_level(0)
+  pub fn as_serialized(&self) -> StackString {
+    capacity_builder::appendable_to_string(self)
   }
 
-  pub fn peer_deps_serialized(&self) -> String {
-    self.peer_serialized_with_level(0)
-  }
-
-  fn as_serialized_with_level(&self, level: usize) -> String {
+  fn as_serialized_with_level<'a, TString: capacity_builder::StringType>(
+    &'a self,
+    builder: &mut StringBuilder<'a, TString>,
+    level: usize,
+  ) {
     // WARNING: This should not change because it's used in the lockfile
-    format!(
-      "{}@{}{}",
-      if level == 0 {
-        Cow::Borrowed(&self.nv.name)
-      } else {
-        Cow::Owned(self.nv.name.replace('/', "+"))
-      },
-      self.nv.version,
-      self.peer_serialized_with_level(level)
-    )
-  }
-
-  fn peer_serialized_with_level(&self, level: usize) -> String {
-    let mut result = String::new();
-    for peer in &self.peer_dependencies {
-      // unfortunately we can't do something like `_3` when
-      // this gets deep because npm package names can start
-      // with a number
-      result.push_str(&"_".repeat(level + 1));
-      result.push_str(&peer.as_serialized_with_level(level + 1));
+    if level == 0 {
+      builder.append(self.nv.name.as_str());
+    } else {
+      builder.append_with_replace(self.nv.name.as_str(), "/", "+");
     }
-    result
+    builder.append('@');
+    builder.append(&self.nv.version);
+    self
+      .peer_dependencies
+      .peer_serialized_with_level(builder, level);
   }
 
   pub fn from_serialized(
@@ -136,9 +194,9 @@ impl NpmPackageId {
 
     fn parse_peers_at_level<'a>(
       level: usize,
-    ) -> impl Fn(&'a str) -> ParseResult<'a, Vec<NpmPackageId>> {
+    ) -> impl Fn(&'a str) -> ParseResult<'a, CowVec<NpmPackageId>> {
       move |mut input| {
-        let mut peers = Vec::new();
+        let mut peers = CowVec::new();
         while let Ok((level_input, _)) = parse_level_at_level(level)(input) {
           input = level_input;
           let peer_result = parse_id_at_level(level)(input)?;
@@ -155,9 +213,9 @@ impl NpmPackageId {
       move |input| {
         let (input, (name, version)) = parse_name_and_version(input)?;
         let name = if level > 0 {
-          name.replace('+', "/")
+          StackString::from_str(name).replace("+", "/")
         } else {
-          name.to_string()
+          StackString::from_str(name)
         };
         let (input, peer_dependencies) =
           parse_peers_at_level(level + 1)(input)?;
@@ -165,7 +223,7 @@ impl NpmPackageId {
           input,
           NpmPackageId {
             nv: PackageNv { name, version },
-            peer_dependencies,
+            peer_dependencies: NpmPackageIdPeerDependencies(peer_dependencies),
           },
         ))
       }
@@ -180,6 +238,15 @@ impl NpmPackageId {
   }
 }
 
+impl<'a> capacity_builder::StringAppendable<'a> for &'a NpmPackageId {
+  fn append_to_builder<TString: capacity_builder::StringType>(
+    self,
+    builder: &mut capacity_builder::StringBuilder<'a, TString>,
+  ) {
+    self.as_serialized_with_level(builder, 0)
+  }
+}
+
 impl Ord for NpmPackageId {
   fn cmp(&self, other: &Self) -> Ordering {
     match self.nv.cmp(&other.nv) {
@@ -226,8 +293,8 @@ impl std::fmt::Display for NpmPackageCacheFolderId {
 
 #[derive(Default, Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
 pub struct NpmResolutionPackageSystemInfo {
-  pub os: Vec<String>,
-  pub cpu: Vec<String>,
+  pub os: Vec<SmallStackString>,
+  pub cpu: Vec<SmallStackString>,
 }
 
 impl NpmResolutionPackageSystemInfo {
@@ -257,10 +324,10 @@ pub struct NpmResolutionPackage {
   pub dist: NpmPackageVersionDistInfo,
   /// Key is what the package refers to the other package as,
   /// which could be different from the package name.
-  pub dependencies: HashMap<String, NpmPackageId>,
-  pub optional_dependencies: HashSet<String>,
+  pub dependencies: HashMap<StackString, NpmPackageId>,
+  pub optional_dependencies: HashSet<StackString>,
   pub bin: Option<NpmPackageVersionBinEntry>,
-  pub scripts: HashMap<String, String>,
+  pub scripts: HashMap<SmallStackString, String>,
   pub deprecated: Option<String>,
 }
 
@@ -313,16 +380,16 @@ impl NpmResolutionPackage {
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
 pub struct NpmSystemInfo {
   /// `process.platform` value from Node.js
-  pub os: String,
+  pub os: SmallStackString,
   /// `process.arch` value from Node.js
-  pub cpu: String,
+  pub cpu: SmallStackString,
 }
 
 impl Default for NpmSystemInfo {
   fn default() -> Self {
     Self {
-      os: node_js_os(std::env::consts::OS).to_string(),
-      cpu: node_js_cpu(std::env::consts::ARCH).to_string(),
+      os: node_js_os(std::env::consts::OS).into(),
+      cpu: node_js_cpu(std::env::consts::ARCH).into(),
     }
   }
 }
@@ -330,13 +397,13 @@ impl Default for NpmSystemInfo {
 impl NpmSystemInfo {
   pub fn from_rust(os: &str, cpu: &str) -> Self {
     Self {
-      os: node_js_os(os).to_string(),
-      cpu: node_js_cpu(cpu).to_string(),
+      os: node_js_os(os).into(),
+      cpu: node_js_cpu(cpu).into(),
     }
   }
 }
 
-fn matches_os_or_cpu_vec(items: &[String], target: &str) -> bool {
+fn matches_os_or_cpu_vec(items: &[SmallStackString], target: &str) -> bool {
   if items.is_empty() {
     return true;
   }
@@ -382,28 +449,30 @@ mod test {
   fn serialize_npm_package_id() {
     let id = NpmPackageId {
       nv: PackageNv::from_str("pkg-a@1.2.3").unwrap(),
-      peer_dependencies: vec![
+      peer_dependencies: NpmPackageIdPeerDependencies::from([
         NpmPackageId {
           nv: PackageNv::from_str("pkg-b@3.2.1").unwrap(),
-          peer_dependencies: vec![
+          peer_dependencies: NpmPackageIdPeerDependencies::from([
             NpmPackageId {
               nv: PackageNv::from_str("pkg-c@1.3.2").unwrap(),
-              peer_dependencies: vec![],
+              peer_dependencies: Default::default(),
             },
             NpmPackageId {
               nv: PackageNv::from_str("pkg-d@2.3.4").unwrap(),
-              peer_dependencies: vec![],
+              peer_dependencies: Default::default(),
             },
-          ],
+          ]),
         },
         NpmPackageId {
           nv: PackageNv::from_str("pkg-e@2.3.1").unwrap(),
-          peer_dependencies: vec![NpmPackageId {
-            nv: PackageNv::from_str("pkg-f@2.3.1").unwrap(),
-            peer_dependencies: vec![],
-          }],
+          peer_dependencies: NpmPackageIdPeerDependencies::from([
+            NpmPackageId {
+              nv: PackageNv::from_str("pkg-f@2.3.1").unwrap(),
+              peer_dependencies: Default::default(),
+            },
+          ]),
         },
-      ],
+      ]),
     };
 
     // this shouldn't change because it's used in the lockfile
@@ -455,33 +524,25 @@ mod test {
   #[test]
   fn test_matches_os_or_cpu_vec() {
     assert!(matches_os_or_cpu_vec(&[], "x64"));
-    assert!(matches_os_or_cpu_vec(&["x64".to_string()], "x64"));
-    assert!(!matches_os_or_cpu_vec(&["!x64".to_string()], "x64"));
-    assert!(matches_os_or_cpu_vec(&["!arm64".to_string()], "x64"));
+    assert!(matches_os_or_cpu_vec(&["x64".into()], "x64"));
+    assert!(!matches_os_or_cpu_vec(&["!x64".into()], "x64"));
+    assert!(matches_os_or_cpu_vec(&["!arm64".into()], "x64"));
     assert!(matches_os_or_cpu_vec(
-      &["!arm64".to_string(), "!x86".to_string()],
+      &["!arm64".into(), "!x86".into()],
       "x64"
     ));
     assert!(!matches_os_or_cpu_vec(
-      &["!arm64".to_string(), "!x86".to_string()],
+      &["!arm64".into(), "!x86".into()],
       "x86"
     ));
     assert!(!matches_os_or_cpu_vec(
-      &[
-        "!arm64".to_string(),
-        "!x86".to_string(),
-        "other".to_string()
-      ],
+      &["!arm64".into(), "!x86".into(), "other".into()],
       "x86"
     ));
 
     // not explicitly excluded and there's an include, so it's considered a match
     assert!(matches_os_or_cpu_vec(
-      &[
-        "!arm64".to_string(),
-        "!x86".to_string(),
-        "other".to_string()
-      ],
+      &["!arm64".into(), "!x86".into(), "other".into()],
       "x64"
     ));
   }
diff --git a/src/registry.rs b/src/registry.rs
index 125ff4f..7968329 100644
--- a/src/registry.rs
+++ b/src/registry.rs
@@ -9,7 +9,10 @@ use std::sync::Arc;
 
 use async_trait::async_trait;
 use deno_semver::npm::NpmVersionReqParseError;
+use deno_semver::package::PackageName;
 use deno_semver::package::PackageNv;
+use deno_semver::SmallStackString;
+use deno_semver::StackString;
 use deno_semver::Version;
 use deno_semver::VersionReq;
 use serde::Deserialize;
@@ -22,7 +25,7 @@ use crate::resolution::NpmPackageVersionNotFound;
 
 #[derive(Debug, Default, Deserialize, Serialize, Clone)]
 pub struct NpmPackageInfo {
-  pub name: String,
+  pub name: PackageName,
   pub versions: HashMap<Version, NpmPackageVersionInfo>,
   #[serde(rename = "dist-tags")]
   pub dist_tags: HashMap<String, Version>,
@@ -82,8 +85,8 @@ impl NpmDependencyEntryKind {
 #[derive(Debug, Clone, Eq, PartialEq)]
 pub struct NpmDependencyEntry {
   pub kind: NpmDependencyEntryKind,
-  pub bare_specifier: String,
-  pub name: String,
+  pub bare_specifier: StackString,
+  pub name: PackageName,
   pub version_req: VersionReq,
   /// When the dependency is also marked as a peer dependency,
   /// use this entry to resolve the dependency when it can't
@@ -135,25 +138,25 @@ pub struct NpmPackageVersionInfo {
   // package and version (ex. `"typescript-3.0.1": "npm:typescript@3.0.1"`).
   #[serde(default)]
   #[serde(deserialize_with = "deserializers::hashmap")]
-  pub dependencies: HashMap<String, String>,
+  pub dependencies: HashMap<StackString, StackString>,
   #[serde(default)]
   #[serde(deserialize_with = "deserializers::hashmap")]
-  pub optional_dependencies: HashMap<String, String>,
+  pub optional_dependencies: HashMap<StackString, StackString>,
   #[serde(default)]
   #[serde(deserialize_with = "deserializers::hashmap")]
-  pub peer_dependencies: HashMap<String, String>,
+  pub peer_dependencies: HashMap<StackString, StackString>,
   #[serde(default)]
   #[serde(deserialize_with = "deserializers::hashmap")]
-  pub peer_dependencies_meta: HashMap<String, NpmPeerDependencyMeta>,
+  pub peer_dependencies_meta: HashMap<StackString, NpmPeerDependencyMeta>,
   #[serde(default)]
   #[serde(deserialize_with = "deserializers::vector")]
-  pub os: Vec<String>,
+  pub os: Vec<SmallStackString>,
   #[serde(default)]
   #[serde(deserialize_with = "deserializers::vector")]
-  pub cpu: Vec<String>,
+  pub cpu: Vec<SmallStackString>,
   #[serde(default)]
   #[serde(deserialize_with = "deserializers::hashmap")]
-  pub scripts: HashMap<String, String>,
+  pub scripts: HashMap<SmallStackString, String>,
   #[serde(default)]
   #[serde(deserialize_with = "deserializers::string")]
   pub deprecated: Option<String>,
@@ -166,7 +169,7 @@ impl NpmPackageVersionInfo {
     package_name: &str,
   ) -> Result<Vec<NpmDependencyEntry>, Box<NpmDependencyEntryError>> {
     fn parse_dep_entry_inner(
-      (key, value): (&String, &String),
+      (key, value): (&StackString, &StackString),
       kind: NpmDependencyEntryKind,
     ) -> Result<NpmDependencyEntry, NpmDependencyEntryErrorSource> {
       let (name, version_req) =
@@ -174,23 +177,23 @@ impl NpmPackageVersionInfo {
       let version_req = VersionReq::parse_from_npm(version_req)?;
       Ok(NpmDependencyEntry {
         kind,
-        bare_specifier: key.to_string(),
-        name: name.to_string(),
+        bare_specifier: key.clone(),
+        name: PackageName::from_str(name),
         version_req,
         peer_dep_version_req: None,
       })
     }
 
     fn parse_dep_entry(
-      nv: (&str, &Version),
-      key_value: (&String, &String),
+      parent_nv: (&str, &Version),
+      key_value: (&StackString, &StackString),
       kind: NpmDependencyEntryKind,
     ) -> Result<NpmDependencyEntry, Box<NpmDependencyEntryError>> {
       parse_dep_entry_inner(key_value, kind).map_err(|source| {
         Box::new(NpmDependencyEntryError {
           parent_nv: PackageNv {
-            name: nv.0.to_string(),
-            version: nv.1.clone(),
+            name: parent_nv.0.into(),
+            version: parent_nv.1.clone(),
           },
           key: key_value.0.to_string(),
           value: key_value.1.to_string(),
@@ -405,7 +408,7 @@ impl TestNpmRegistryApi {
       self.add_package_info(
         name,
         NpmPackageInfo {
-          name: name.to_string(),
+          name: name.into(),
           ..Default::default()
         },
       );
@@ -473,9 +476,7 @@ impl TestNpmRegistryApi {
 
   pub fn add_dependency(&self, package: (&str, &str), entry: (&str, &str)) {
     self.with_version_info(package, |version| {
-      version
-        .dependencies
-        .insert(entry.0.to_string(), entry.1.to_string());
+      version.dependencies.insert(entry.0.into(), entry.1.into());
     })
   }
 
@@ -485,12 +486,10 @@ impl TestNpmRegistryApi {
     entry: (&str, &str),
   ) {
     self.with_version_info(package, |version| {
-      version
-        .dependencies
-        .insert(entry.0.to_string(), entry.1.to_string());
+      version.dependencies.insert(entry.0.into(), entry.1.into());
       version
         .optional_dependencies
-        .insert(entry.0.to_string(), entry.1.to_string());
+        .insert(entry.0.into(), entry.1.into());
     })
   }
 
@@ -498,7 +497,7 @@ impl TestNpmRegistryApi {
     self.with_version_info(package, |version| {
       version
         .optional_dependencies
-        .insert(entry.0.to_string(), entry.1.to_string());
+        .insert(entry.0.into(), entry.1.into());
     })
   }
 
@@ -510,7 +509,7 @@ impl TestNpmRegistryApi {
     self.with_version_info(package, |version| {
       version
         .peer_dependencies
-        .insert(entry.0.to_string(), entry.1.to_string());
+        .insert(entry.0.into(), entry.1.into());
     });
   }
 
@@ -522,11 +521,10 @@ impl TestNpmRegistryApi {
     self.with_version_info(package, |version| {
       version
         .peer_dependencies
-        .insert(entry.0.to_string(), entry.1.to_string());
-      version.peer_dependencies_meta.insert(
-        entry.0.to_string(),
-        NpmPeerDependencyMeta { optional: true },
-      );
+        .insert(entry.0.into(), entry.1.into());
+      version
+        .peer_dependencies_meta
+        .insert(entry.0.into(), NpmPeerDependencyMeta { optional: true });
     });
   }
 }
@@ -1124,7 +1122,7 @@ mod test {
     let info: NpmPackageVersionInfo = serde_json::from_str(text).unwrap();
     assert_eq!(
       info.dependencies,
-      HashMap::from([("value10".to_string(), "valid".to_string())])
+      HashMap::from([("value10".into(), "valid".into())])
     );
     assert_eq!(info.os, Vec::from(["valid".to_string()]));
   }
@@ -1171,15 +1169,21 @@ mod test {
       ("test", "npm:@scope/package@1", ("@scope/package", "1")),
     ];
     for (key, value, expected_result) in cases {
-      let result = parse_dep_entry_name_and_raw_version(key, value).unwrap();
-      assert_eq!(result, expected_result);
+      let key = StackString::from(key);
+      let value = StackString::from(value);
+      let (name, version) =
+        parse_dep_entry_name_and_raw_version(&key, &value).unwrap();
+      assert_eq!((name, version), expected_result);
     }
   }
 
   #[test]
   fn test_parse_dep_entry_name_and_raw_version_error() {
-    let err =
-      parse_dep_entry_name_and_raw_version("test", "git:somerepo").unwrap_err();
+    let err = parse_dep_entry_name_and_raw_version(
+      &StackString::from("test"),
+      &StackString::from("git:somerepo"),
+    )
+    .unwrap_err();
     match err {
       NpmDependencyEntryErrorSource::RemoteDependency { specifier } => {
         assert_eq!(specifier, "git:somerepo")
@@ -1196,7 +1200,7 @@ mod test {
       "git+ssh://github.com/example/example",
     ] {
       let deps = NpmPackageVersionInfo {
-        dependencies: HashMap::from([("a".to_string(), specifier.to_string())]),
+        dependencies: HashMap::from([("a".into(), specifier.into())]),
         ..Default::default()
       };
       let err = deps.dependencies_as_entries("pkg-name").unwrap_err();
diff --git a/src/resolution/common.rs b/src/resolution/common.rs
index 3fff615..b20c524 100644
--- a/src/resolution/common.rs
+++ b/src/resolution/common.rs
@@ -1,6 +1,7 @@
 // Copyright 2018-2024 the Deno authors. MIT license.
 
 use deno_semver::package::PackageNv;
+use deno_semver::StackString;
 use deno_semver::Version;
 use deno_semver::VersionReq;
 use deno_semver::WILDCARD_VERSION_REQ;
@@ -23,14 +24,14 @@ pub enum NpmPackageVersionResolutionError {
   )]
   DistTagNotFound {
     dist_tag: String,
-    package_name: String,
+    package_name: StackString,
   },
   #[class(type)]
   #[error(
     "Could not find version '{version}' referenced in dist-tag '{dist_tag}' for npm package '{package_name}'."
   )]
   DistTagVersionNotFound {
-    package_name: String,
+    package_name: StackString,
     dist_tag: String,
     version: String,
   },
@@ -42,7 +43,7 @@ pub enum NpmPackageVersionResolutionError {
     "Could not find npm package '{package_name}' matching '{version_req}'."
   )]
   VersionReqNotMatched {
-    package_name: String,
+    package_name: StackString,
     version_req: VersionReq,
   },
 }
@@ -224,10 +225,10 @@ mod test {
     // dist tag where version doesn't exist
     let package_req = PackageReq::from_str("test@latest").unwrap();
     let package_info = NpmPackageInfo {
-      name: "test".to_string(),
+      name: "test".into(),
       versions: HashMap::new(),
       dist_tags: HashMap::from([(
-        "latest".to_string(),
+        "latest".into(),
         Version::parse_from_npm("1.0.0-alpha").unwrap(),
       )]),
     };
@@ -246,7 +247,7 @@ mod test {
     // dist tag where version is a pre-release
     let package_req = PackageReq::from_str("test@latest").unwrap();
     let package_info = NpmPackageInfo {
-      name: "test".to_string(),
+      name: "test".into(),
       versions: HashMap::from([
         (
           Version::parse_from_npm("0.1.0").unwrap(),
@@ -261,7 +262,7 @@ mod test {
         ),
       ]),
       dist_tags: HashMap::from([(
-        "latest".to_string(),
+        "latest".into(),
         Version::parse_from_npm("1.0.0-alpha").unwrap(),
       )]),
     };
@@ -278,7 +279,7 @@ mod test {
     // for the "types_node_version_req" even though the latest is 1.1.0
     let package_req = PackageReq::from_str("@types/node").unwrap();
     let package_info = NpmPackageInfo {
-      name: "@types/node".to_string(),
+      name: "@types/node".into(),
       versions: HashMap::from([
         (
           Version::parse_from_npm("1.0.0").unwrap(),
@@ -296,7 +297,7 @@ mod test {
         ),
       ]),
       dist_tags: HashMap::from([(
-        "latest".to_string(),
+        "latest".into(),
         Version::parse_from_npm("1.1.0").unwrap(),
       )]),
     };
@@ -316,7 +317,7 @@ mod test {
   fn test_wildcard_version_req() {
     let package_req = PackageReq::from_str("some-pkg").unwrap();
     let package_info = NpmPackageInfo {
-      name: "some-pkg".to_string(),
+      name: "some-pkg".into(),
       versions: HashMap::from([
         (
           Version::parse_from_npm("1.0.0-rc.1").unwrap(),
@@ -334,7 +335,7 @@ mod test {
         ),
       ]),
       dist_tags: HashMap::from([(
-        "latest".to_string(),
+        "latest".into(),
         Version::parse_from_npm("1.0.0-rc.1").unwrap(),
       )]),
     };
@@ -351,7 +352,7 @@ mod test {
   #[test]
   fn test_latest_tag_version_req() {
     let package_info = NpmPackageInfo {
-      name: "some-pkg".to_string(),
+      name: "some-pkg".into(),
       versions: HashMap::from([
         (
           Version::parse_from_npm("0.1.0-alpha.1").unwrap(),
@@ -384,11 +385,11 @@ mod test {
       ]),
       dist_tags: HashMap::from([
         (
-          "latest".to_string(),
+          "latest".into(),
           Version::parse_from_npm("0.1.0-alpha.2").unwrap(),
         ),
         (
-          "dev".to_string(),
+          "dev".into(),
           Version::parse_from_npm("0.1.0-beta.2").unwrap(),
         ),
       ]),
diff --git a/src/resolution/graph.rs b/src/resolution/graph.rs
index 2d9a324..4d5fb15 100644
--- a/src/resolution/graph.rs
+++ b/src/resolution/graph.rs
@@ -1,7 +1,9 @@
 // Copyright 2018-2024 the Deno authors. MIT license.
 
+use deno_semver::package::PackageName;
 use deno_semver::package::PackageNv;
 use deno_semver::package::PackageReq;
+use deno_semver::StackString;
 use deno_semver::Version;
 use deno_semver::VersionReq;
 use futures::StreamExt;
@@ -64,7 +66,7 @@ struct Node {
   /// Note: We don't want to store the children as a `NodeRef` because
   /// multiple paths might visit through the children and we don't want
   /// to share those references with those paths.
-  pub children: BTreeMap<String, NodeId>,
+  pub children: BTreeMap<StackString, NodeId>,
   /// Whether the node has demonstrated to have no peer dependencies in its
   /// descendants. If this is true then we can skip analyzing this node
   /// again when we encounter it another time in the dependency tree, which
@@ -213,7 +215,7 @@ enum GraphPathNodeOrRoot {
 struct GraphPath {
   previous_node: Option<GraphPathNodeOrRoot>,
   node_id_ref: NodeIdRef,
-  specifier: String,
+  specifier: StackString,
   // we could consider not storing this here and instead reference the resolved
   // nodes, but we should performance profile this code first
   nv: Rc<PackageNv>,
@@ -228,7 +230,7 @@ impl GraphPath {
       previous_node: Some(GraphPathNodeOrRoot::Root(nv.clone())),
       node_id_ref: NodeIdRef::new(node_id),
       // use an empty specifier
-      specifier: "".to_string(),
+      specifier: "".into(),
       nv,
       linked_circular_descendants: Default::default(),
     })
@@ -238,7 +240,7 @@ impl GraphPath {
     self.node_id_ref.get()
   }
 
-  pub fn specifier(&self) -> &str {
+  pub fn specifier(&self) -> &StackString {
     &self.specifier
   }
 
@@ -249,7 +251,7 @@ impl GraphPath {
   pub fn with_id(
     self: &Rc<GraphPath>,
     node_id: NodeId,
-    specifier: String,
+    specifier: StackString,
     nv: Rc<PackageNv>,
   ) -> Rc<Self> {
     Rc::new(Self {
@@ -324,7 +326,7 @@ pub struct Graph {
   /// Note: Uses a BTreeMap in order to create some determinism
   /// when creating the snapshot.
   root_packages: BTreeMap<Rc<PackageNv>, NodeId>,
-  package_name_versions: HashMap<String, HashSet<Version>>,
+  package_name_versions: HashMap<StackString, HashSet<Version>>,
   nodes: HashMap<NodeId, Node>,
   resolved_node_ids: ResolvedNodeIds,
   // This will be set when creating from a snapshot, then
@@ -467,12 +469,12 @@ impl Graph {
     if resolved_id.peer_dependencies.is_empty() {
       NpmPackageId {
         nv: (*resolved_id.nv).clone(),
-        peer_dependencies: Vec::new(),
+        peer_dependencies: Default::default(),
       }
     } else {
       let mut npm_pkg_id = NpmPackageId {
         nv: (*resolved_id.nv).clone(),
-        peer_dependencies: Vec::with_capacity(
+        peer_dependencies: crate::NpmPackageIdPeerDependencies::with_capacity(
           resolved_id.peer_dependencies.len(),
         ),
       };
@@ -498,7 +500,7 @@ impl Graph {
           } else {
             npm_pkg_id.peer_dependencies.push(NpmPackageId {
               nv: (*child_resolved_id.nv).clone(),
-              peer_dependencies: Vec::new(),
+              peer_dependencies: Default::default(),
             });
           }
         }
@@ -584,12 +586,12 @@ impl Graph {
   fn set_child_of_parent_node(
     &mut self,
     parent_id: NodeId,
-    specifier: &str,
+    specifier: &StackString,
     child_id: NodeId,
   ) {
     assert_ne!(child_id, parent_id);
     let parent = self.borrow_node_mut(parent_id);
-    parent.children.insert(specifier.to_string(), child_id);
+    parent.children.insert(specifier.clone(), child_id);
   }
 
   pub async fn into_snapshot<TNpmRegistryApi: NpmRegistryApi>(
@@ -608,7 +610,7 @@ impl Graph {
       );
     let mut packages: HashMap<NpmPackageId, NpmResolutionPackage> =
       HashMap::with_capacity(self.nodes.len());
-    let mut packages_by_name: HashMap<String, Vec<_>> =
+    let mut packages_by_name: HashMap<PackageName, Vec<_>> =
       HashMap::with_capacity(self.nodes.len());
 
     // todo(dsherret): there is a lurking bug within the peer dependencies code.
@@ -790,7 +792,7 @@ impl DepEntryCache {
 }
 
 struct UnresolvedOptionalPeer {
-  specifier: String,
+  specifier: StackString,
   graph_path: Rc<GraphPath>,
 }
 
@@ -871,11 +873,8 @@ impl<'a, TNpmRegistryApi: NpmRegistryApi>
         child_id = ancestor.node_id();
       }
 
-      let new_path = parent_path.with_id(
-        child_id,
-        entry.bare_specifier.to_string(),
-        child_nv,
-      );
+      let new_path =
+        parent_path.with_id(child_id, entry.bare_specifier.clone(), child_nv);
       if let Some(ancestor) = maybe_ancestor {
         // this node is circular, so we link it to the ancestor
         self.add_linked_circular_descendant(&ancestor, new_path);
@@ -910,7 +909,7 @@ impl<'a, TNpmRegistryApi: NpmRegistryApi>
     )?;
     let resolved_id = ResolvedId {
       nv: Rc::new(PackageNv {
-        name: package_info.name.to_string(),
+        name: package_info.name.clone(),
         version: info.version.clone(),
       }),
       peer_dependencies: Vec::new(),
@@ -935,7 +934,7 @@ impl<'a, TNpmRegistryApi: NpmRegistryApi>
       "{} - Resolved {}@{} to {}",
       match parent_id {
         Some(parent_id) => self.graph.get_npm_pkg_id(parent_id).as_serialized(),
-        None => "<package-req>".to_string(),
+        None => "<package-req>".into(),
       },
       pkg_req_name,
       version_req.version_text(),
@@ -1117,7 +1116,7 @@ impl<'a, TNpmRegistryApi: NpmRegistryApi>
 
   fn resolve_peer_dep(
     &mut self,
-    specifier: &str,
+    specifier: &StackString,
     peer_dep: &NpmDependencyEntry,
     peer_package_info: &NpmPackageInfo,
     ancestor_path: &Rc<GraphPath>,
@@ -1328,7 +1327,7 @@ impl<'a, TNpmRegistryApi: NpmRegistryApi>
           let parent_node = self.graph.borrow_node_mut(parent_node_id);
           parent_node
             .children
-            .insert(graph_path_node.specifier().to_string(), new_node_id);
+            .insert(graph_path_node.specifier().clone(), new_node_id);
         }
       }
     }
@@ -1339,7 +1338,7 @@ impl<'a, TNpmRegistryApi: NpmRegistryApi>
     // path from the node above the resolved dep to just above the peer dep
     path: &[&Rc<GraphPath>],
     peer_dep_parent: GraphPathNodeOrRoot,
-    peer_dep_specifier: &str,
+    peer_dep_specifier: &StackString,
     peer_dep_id: NodeId,
   ) {
     debug_assert!(!path.is_empty());
@@ -1380,11 +1379,8 @@ impl<'a, TNpmRegistryApi: NpmRegistryApi>
     );
 
     // queue next step
-    let new_path = bottom_node.with_id(
-      peer_dep_id,
-      peer_dep_specifier.to_string(),
-      peer_dep_nv,
-    );
+    let new_path =
+      bottom_node.with_id(peer_dep_id, peer_dep_specifier.clone(), peer_dep_nv);
     if let Some(ancestor_node) = maybe_circular_ancestor {
       // it's circular, so link this in step with the ancestor node
       ancestor_node
@@ -3835,10 +3831,10 @@ mod test {
     api.add_dependency(("package-c", "1.0.0"), ("package-d", "1"));
     api.add_optional_dep(("package-d", "1.0.0"), ("package-e", "1"));
     api.with_version_info(("package-c", "1.0.0"), |info| {
-      info.os = vec!["win32".to_string(), "darwin".to_string()];
+      info.os = vec!["win32".into(), "darwin".into()];
     });
     api.with_version_info(("package-e", "1.0.0"), |info| {
-      info.os = vec!["win32".to_string()];
+      info.os = vec!["win32".into()];
     });
 
     let snapshot =
@@ -3846,8 +3842,8 @@ mod test {
     let packages = package_names_with_info(
       &snapshot,
       &NpmSystemInfo {
-        os: "win32".to_string(),
-        cpu: "x86".to_string(),
+        os: "win32".into(),
+        cpu: "x86".into(),
       },
     );
     assert_eq!(
@@ -3864,8 +3860,8 @@ mod test {
     let packages = package_names_with_info(
       &snapshot,
       &NpmSystemInfo {
-        os: "darwin".to_string(),
-        cpu: "x86".to_string(),
+        os: "darwin".into(),
+        cpu: "x86".into(),
       },
     );
     assert_eq!(
@@ -3881,8 +3877,8 @@ mod test {
     let packages = package_names_with_info(
       &snapshot,
       &NpmSystemInfo {
-        os: "linux".to_string(),
-        cpu: "x86".to_string(),
+        os: "linux".into(),
+        cpu: "x86".into(),
       },
     );
     assert_eq!(
@@ -3912,10 +3908,10 @@ mod test {
     api.add_dep_and_optional_dep(("package-d", "1.0.0"), ("package-e", "1"));
 
     api.with_version_info(("package-c", "1.0.0"), |info| {
-      info.os = vec!["win32".to_string()];
+      info.os = vec!["win32".into()];
     });
     api.with_version_info(("package-e", "1.0.0"), |info| {
-      info.os = vec!["win32".to_string()];
+      info.os = vec!["win32".into()];
     });
 
     let snapshot =
@@ -3924,8 +3920,8 @@ mod test {
     let packages = package_names_with_info(
       &snapshot,
       &NpmSystemInfo {
-        os: "darwin".to_string(),
-        cpu: "x86".to_string(),
+        os: "darwin".into(),
+        cpu: "x86".into(),
       },
     );
     assert_eq!(
@@ -3971,8 +3967,8 @@ mod test {
     let packages = package_names_with_info(
       &snapshot,
       &NpmSystemInfo {
-        os: "darwin".to_string(),
-        cpu: "x86_64".to_string(),
+        os: "darwin".into(),
+        cpu: "x86_64".into(),
       },
     );
     assert_eq!(packages, vec!["package-a@1.0.0".to_string()]);
@@ -3993,8 +3989,8 @@ mod test {
     let packages = package_names_with_info(
       &snapshot,
       &NpmSystemInfo {
-        os: "darwin".to_string(),
-        cpu: "x86_64".to_string(),
+        os: "darwin".into(),
+        cpu: "x86_64".into(),
       },
     );
     assert_eq!(
@@ -4018,7 +4014,7 @@ mod test {
           system: Default::default(),
           dist: Default::default(),
           dependencies: HashMap::from([(
-            "package-a".to_string(),
+            "package-a".into(),
             NpmPackageId::from_serialized("package-0@1.0.0").unwrap(),
           )]),
           optional_dependencies: HashSet::new(),
@@ -4056,7 +4052,12 @@ mod test {
       .map(|(a, b)| {
         (
           a.to_string(),
-          snapshot.root_packages.get(&b).unwrap().as_serialized(),
+          snapshot
+            .root_packages
+            .get(&b)
+            .unwrap()
+            .as_serialized()
+            .to_string(),
         )
       })
       .collect::<Vec<_>>();
@@ -4065,12 +4066,14 @@ mod test {
     let packages = packages
       .into_iter()
       .map(|pkg| TestNpmResolutionPackage {
-        pkg_id: pkg.id.as_serialized(),
+        pkg_id: pkg.id.as_serialized().to_string(),
         copy_index: pkg.copy_index,
         dependencies: pkg
           .dependencies
           .into_iter()
-          .map(|(key, value)| (key, value.as_serialized()))
+          .map(|(key, value)| {
+            (key.to_string(), value.as_serialized().to_string())
+          })
           .collect(),
       })
       .collect();
@@ -4085,7 +4088,7 @@ mod test {
     let mut packages = snapshot
       .all_system_packages(system_info)
       .into_iter()
-      .map(|p| p.id.as_serialized())
+      .map(|p| p.id.as_serialized().to_string())
       .collect::<Vec<_>>();
     packages.sort();
     let mut serialized_pkgs = snapshot
@@ -4093,7 +4096,7 @@ mod test {
       .into_serialized()
       .packages
       .into_iter()
-      .map(|p| p.id.as_serialized())
+      .map(|p| p.id.as_serialized().to_string())
       .collect::<Vec<_>>();
     serialized_pkgs.sort();
     // ensure the output of both of these are the same
diff --git a/src/resolution/snapshot.rs b/src/resolution/snapshot.rs
index 25c7e72..c0588dd 100644
--- a/src/resolution/snapshot.rs
+++ b/src/resolution/snapshot.rs
@@ -4,6 +4,8 @@ use deno_error::JsError;
 use deno_lockfile::Lockfile;
 use deno_semver::package::PackageNv;
 use deno_semver::package::PackageReq;
+use deno_semver::SmallStackString;
+use deno_semver::StackString;
 use deno_semver::VersionReq;
 use futures::stream::FuturesOrdered;
 use futures::StreamExt;
@@ -112,10 +114,10 @@ pub struct SerializedNpmResolutionSnapshotPackage {
   pub dist: NpmPackageVersionDistInfo,
   /// Key is what the package refers to the other package as,
   /// which could be different from the package name.
-  pub dependencies: HashMap<String, NpmPackageId>,
-  pub optional_dependencies: HashSet<String>,
+  pub dependencies: HashMap<StackString, NpmPackageId>,
+  pub optional_dependencies: HashSet<StackString>,
   pub bin: Option<NpmPackageVersionBinEntry>,
-  pub scripts: HashMap<String, String>,
+  pub scripts: HashMap<SmallStackString, String>,
   pub deprecated: Option<String>,
 }
 
@@ -220,7 +222,7 @@ pub struct NpmResolutionSnapshot {
   pub(super) package_reqs: HashMap<PackageReq, PackageNv>,
   // Each root level npm package name and version maps to an exact npm package node id.
   pub(super) root_packages: HashMap<PackageNv, NpmPackageId>,
-  pub(super) packages_by_name: HashMap<String, Vec<NpmPackageId>>,
+  pub(super) packages_by_name: HashMap<StackString, Vec<NpmPackageId>>,
   pub(super) packages: HashMap<NpmPackageId, NpmResolutionPackage>,
 }
 
@@ -234,7 +236,7 @@ impl NpmResolutionSnapshot {
       snapshot.root_packages.len(),
     );
     let mut packages_by_name =
-      HashMap::<String, Vec<NpmPackageId>>::with_capacity(
+      HashMap::<StackString, Vec<NpmPackageId>>::with_capacity(
         snapshot.packages.len(),
       ); // close enough
     let mut packages =
@@ -253,7 +255,7 @@ impl NpmResolutionSnapshot {
     // then the packages
     for package in snapshot.packages {
       packages_by_name
-        .entry(package.id.nv.name.to_string())
+        .entry(package.id.nv.name.clone())
         .or_default()
         .push(package.id.clone());
 
@@ -370,7 +372,7 @@ impl NpmResolutionSnapshot {
   pub fn subset(&self, package_reqs: &[PackageReq]) -> Self {
     let mut new_package_reqs = HashMap::with_capacity(package_reqs.len());
     let mut packages = HashMap::with_capacity(package_reqs.len() * 2);
-    let mut packages_by_name: HashMap<String, Vec<NpmPackageId>> =
+    let mut packages_by_name: HashMap<StackString, Vec<NpmPackageId>> =
       HashMap::with_capacity(package_reqs.len());
     let mut root_packages = HashMap::with_capacity(package_reqs.len());
 
@@ -395,7 +397,7 @@ impl NpmResolutionSnapshot {
         continue;
       };
       packages_by_name
-        .entry(package.id.nv.name.to_string())
+        .entry(package.id.nv.name.clone())
         .or_default()
         .push(package.id.clone());
       let Some(package) = self.package_from_id(id) else {
@@ -819,7 +821,7 @@ pub enum IncompleteSnapshotFromLockfileError {
 struct IncompletePackageInfo {
   id: NpmPackageId,
   integrity: String,
-  dependencies: HashMap<String, NpmPackageId>,
+  dependencies: HashMap<StackString, NpmPackageId>,
 }
 
 pub struct IncompleteSnapshot {
@@ -1101,7 +1103,7 @@ mod tests {
           dependencies: deps(&[("b", "b@1.0.0"), ("c", "c@1.0.0")]),
           system: Default::default(),
           dist: Default::default(),
-          optional_dependencies: HashSet::from(["c".to_string()]),
+          optional_dependencies: HashSet::from(["c".into()]),
           bin: None,
           scripts: Default::default(),
           deprecated: Default::default(),
@@ -1120,8 +1122,8 @@ mod tests {
           id: NpmPackageId::from_serialized("c@1.0.0").unwrap(),
           dependencies: deps(&[("b", "b@1.0.0"), ("d", "d@1.0.0")]),
           system: NpmResolutionPackageSystemInfo {
-            os: vec!["win32".to_string()],
-            cpu: vec!["x64".to_string()],
+            os: vec!["win32".into()],
+            cpu: vec!["x64".into()],
           },
           dist: Default::default(),
           optional_dependencies: Default::default(),
@@ -1148,8 +1150,8 @@ mod tests {
     {
       let mut actual = snapshot
         .as_valid_serialized_for_system(&NpmSystemInfo {
-          os: "win32".to_string(),
-          cpu: "x64".to_string(),
+          os: "win32".into(),
+          cpu: "x64".into(),
         })
         .into_serialized();
       actual.packages.sort_by(|a, b| a.id.cmp(&b.id));
@@ -1165,8 +1167,8 @@ mod tests {
     {
       let mut actual = snapshot
         .as_valid_serialized_for_system(&NpmSystemInfo {
-          os: "darwin".to_string(),
-          cpu: "x64".to_string(),
+          os: "darwin".into(),
+          cpu: "x64".into(),
         })
         .into_serialized();
       actual.packages.sort_by(|a, b| a.id.cmp(&b.id));
@@ -1234,7 +1236,7 @@ mod tests {
   ) -> NpmPackageCacheFolderId {
     NpmPackageCacheFolderId {
       nv: PackageNv {
-        name: name.to_string(),
+        name: name.into(),
         version: Version::parse_standard(version).unwrap(),
       },
       copy_index,
@@ -1254,12 +1256,12 @@ mod tests {
     }
   }
 
-  fn deps(deps: &[(&str, &str)]) -> HashMap<String, NpmPackageId> {
+  fn deps(deps: &[(&str, &str)]) -> HashMap<StackString, NpmPackageId> {
     deps
       .iter()
       .map(|(key, value)| {
         (
-          key.to_string(),
+          StackString::from(*key),
           NpmPackageId::from_serialized(value).unwrap(),
         )
       })