diff --git a/Cargo.lock b/Cargo.lock
index b988226..1edd0b9 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -67,12 +67,33 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "86fdf8605db99b54d3cd748a44c6d04df638eb5dafb219b135d0149bd0db01f6"
 
 [[package]]
-name = "bincode"
-version = "1.3.3"
+name = "array-init"
+version = "2.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b1f45e9417d87227c7a56d22e471c6206462cba514c7590c09aff4cf6d1ddcad"
+checksum = "3d62b7694a562cdf5a74227903507c56ab2cc8bdd1f781ed5cb4cf9c9f810bfc"
+
+[[package]]
+name = "binrw"
+version = "0.14.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7d4bca59c20d6f40c2cc0802afbe1e788b89096f61bdf7aeea6bf00f10c2909b"
 dependencies = [
- "serde",
+ "array-init",
+ "binrw_derive",
+ "bytemuck",
+]
+
+[[package]]
+name = "binrw_derive"
+version = "0.14.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d8ba42866ce5bced2645bfa15e97eef2c62d2bdb530510538de8dd3d04efff3c"
+dependencies = [
+ "either",
+ "owo-colors",
+ "proc-macro2",
+ "quote",
+ "syn 1.0.109",
 ]
 
 [[package]]
@@ -81,6 +102,12 @@ version = "3.16.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "79296716171880943b8470b5f8d03aa55eb2e645a4874bdbb28adb49162e012c"
 
+[[package]]
+name = "bytemuck"
+version = "1.19.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8334215b81e418a0a7bdb8ef0849474f40bb10c8b71f1c4ed315cff49f32494d"
+
 [[package]]
 name = "cc"
 version = "1.1.30"
@@ -127,7 +154,7 @@ dependencies = [
  "heck",
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.79",
 ]
 
 [[package]]
@@ -142,6 +169,12 @@ version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d3fd119d74b830634cea2a0f58bbd0d54540518a14397557951e79340abc28c0"
 
+[[package]]
+name = "either"
+version = "1.13.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "60b1af1c220855b6ceac025d3f6ecdd2b7c4894bfe9cd9bda4fbb4bc7c0d4cf0"
+
 [[package]]
 name = "fixx"
 version = "0.0.0-git"
@@ -212,7 +245,7 @@ checksum = "bbd2bcb4c963f2ddae06a2efc7e9f3591312473c50c6685e1f298068316e66fe"
 name = "libixx"
 version = "0.0.0-git"
 dependencies = [
- "bincode",
+ "binrw",
  "serde",
  "serde_json",
  "thiserror",
@@ -245,6 +278,12 @@ version = "1.20.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1261fe7e33c73b354eab43b1273a57c8f967d0391e80353e51f764ac02cf6775"
 
+[[package]]
+name = "owo-colors"
+version = "3.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c1b04fb49957986fdce4d6ee7a65027d55d4b6d2265e5848bbb507b58ccfdb6f"
+
 [[package]]
 name = "percent-encoding"
 version = "2.3.1"
@@ -321,7 +360,7 @@ checksum = "243902eda00fad750862fc144cea25caca5e20d615af0a81bee94ca738f1df1f"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.79",
 ]
 
 [[package]]
@@ -354,6 +393,17 @@ version = "0.11.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7da8b5736845d9f2fcb837ea5d9e2628564b3b043a70948a3f0b778838c5fb4f"
 
+[[package]]
+name = "syn"
+version = "1.0.109"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "72b64191b275b66ffe2469e8af2c1cfe3bafa67b529ead792a6d0160888b4237"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
 [[package]]
 name = "syn"
 version = "2.0.79"
@@ -382,7 +432,7 @@ checksum = "08904e7672f5eb876eaaf87e0ce17857500934f4981c4a0ab2b4aa98baac7fc3"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.79",
 ]
 
 [[package]]
@@ -508,7 +558,7 @@ dependencies = [
  "once_cell",
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.79",
  "wasm-bindgen-shared",
 ]
 
@@ -530,7 +580,7 @@ checksum = "26c6ab57572f7a24a4985830b120de1594465e5d500f24afe89e16b4e833ef68"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.79",
  "wasm-bindgen-backend",
  "wasm-bindgen-shared",
 ]
diff --git a/libixx/Cargo.toml b/libixx/Cargo.toml
index 45d4ec0..4ca5bbe 100644
--- a/libixx/Cargo.toml
+++ b/libixx/Cargo.toml
@@ -8,7 +8,7 @@ license = "MIT OR Apache-2.0"
 [dependencies]
 serde = { version = "1.0", features = ["derive"] }
 thiserror = "1.0"
-bincode = "1.3"
+binrw = "0.14"
 
 [dev-dependencies]
 serde_json = "1.0"
diff --git a/libixx/src/error.rs b/libixx/src/error.rs
index 09374e7..b8e85a1 100644
--- a/libixx/src/error.rs
+++ b/libixx/src/error.rs
@@ -1,3 +1,5 @@
+use std::string::FromUtf8Error;
+
 use thiserror::Error;
 
 #[derive(Error, Debug)]
@@ -8,5 +10,7 @@ pub enum IxxError {
   RecursiveReference,
 
   #[error("(de)serialization failed")]
-  Bincode(#[from] bincode::Error),
+  Binrw(#[from] binrw::Error),
+  #[error("invalid utf8")]
+  FromUtf8Error(#[from] FromUtf8Error),
 }
diff --git a/libixx/src/index.rs b/libixx/src/index.rs
index 723686a..f30c1f1 100644
--- a/libixx/src/index.rs
+++ b/libixx/src/index.rs
@@ -1,49 +1,64 @@
-use std::io::{Read, Write};
+use std::io::{Cursor, Read, Seek, Write};
 
-use serde::{Deserialize, Serialize};
+use binrw::{binrw, BinRead, BinWrite, Endian, NullString};
 
 use crate::IxxError;
 
-#[derive(Default, Debug, Clone, PartialEq, Serialize, Deserialize)]
-pub struct Index(Vec<Vec<Label>>);
+#[binrw(magic = b"ixx01", little)]
+#[derive(Default, Debug, Clone, PartialEq)]
+pub struct Index {
+  #[bw(calc = entries.len() as u32)]
+  count: u32,
+  #[br(count = count)]
+  entries: Vec<Entry>,
+}
+
+#[binrw]
+#[derive(Default, Debug, Clone, PartialEq)]
+pub struct Entry {
+  #[bw(calc = labels.len() as u16)]
+  count: u16,
+  #[br(count = count)]
+  labels: Vec<Label>,
+}
 
-#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+#[binrw]
+#[derive(Debug, Clone, PartialEq)]
 struct Reference {
   option_idx: u16,
   label_idx: u8,
 }
 
-#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+#[binrw]
+#[derive(Debug, Clone, PartialEq)]
 enum Label {
-  InPlace(String),
+  InPlace(NullString),
   Reference(Reference),
 }
 
 impl Index {
   pub fn read(buf: &[u8]) -> Result<Self, IxxError> {
-    Ok(bincode::deserialize(buf)?)
+    Self::read_from(&mut Cursor::new(buf))
   }
 
-  pub fn read_from<R: Read>(read: &mut R) -> Result<Self, IxxError> {
-    Ok(bincode::deserialize_from(read)?)
+  pub fn read_from<R: Read + Seek>(read: &mut R) -> Result<Self, IxxError> {
+    Ok(BinRead::read_options(read, Endian::Little, ())?)
   }
 
-  pub fn write(&self) -> Result<Vec<u8>, IxxError> {
-    Ok(bincode::serialize(self)?)
-  }
-
-  pub fn write_into<W: Write>(&self, write: &mut W) -> Result<(), IxxError> {
-    Ok(bincode::serialize_into(write, self)?)
+  pub fn write_into<W: Write + Seek>(&self, write: &mut W) -> Result<(), IxxError> {
+    Ok(BinWrite::write_options(self, write, Endian::Little, ())?)
   }
 
   pub fn push(&mut self, option: &str) {
     let labels = option
       .split('.')
       .map(|segment| {
-        for (option_idx, option) in self.0.iter().enumerate() {
+        let segment = segment.into();
+
+        for (option_idx, Entry { labels: option }) in self.entries.iter().enumerate() {
           for (label_idx, label) in option.iter().enumerate() {
             if let Label::InPlace(inplace) = label {
-              if inplace != segment {
+              if inplace != &segment {
                 continue;
               }
 
@@ -55,21 +70,21 @@ impl Index {
           }
         }
 
-        Label::InPlace(segment.to_string())
+        Label::InPlace(segment)
       })
       .collect();
 
-    self.0.push(labels);
+    self.entries.push(Entry { labels });
   }
 
-  fn resolve_reference(&self, reference: &Reference) -> Result<&str, IxxError> {
+  fn resolve_reference(&self, reference: &Reference) -> Result<&NullString, IxxError> {
     let option_idx = reference.option_idx as usize;
 
-    if self.0.len() <= option_idx {
+    if self.entries.len() <= option_idx {
       return Err(IxxError::ReferenceOutOfBounds);
     }
 
-    let entry = &self.0[option_idx];
+    let entry = &self.entries[option_idx].labels;
 
     let label_idx = reference.label_idx as usize;
 
@@ -88,11 +103,13 @@ impl Index {
   pub fn get_idx_by_name(&self, option: &str) -> Result<Option<usize>, IxxError> {
     let mut labels = Vec::new();
     for segment in option.split('.') {
+      let segment = segment.into();
+
       'outer: {
-        for (option_idx, option) in self.0.iter().enumerate() {
+        for (option_idx, Entry { labels: option }) in self.entries.iter().enumerate() {
           for (label_idx, label) in option.iter().enumerate() {
             if let Label::InPlace(inplace) = label {
-              if inplace != segment {
+              if inplace != &segment {
                 continue;
               }
 
@@ -111,10 +128,10 @@ impl Index {
 
     Ok(
       self
-        .0
+        .entries
         .iter()
         .enumerate()
-        .find(|(idx, option)| do_labels_match(*idx, option, &labels))
+        .find(|(idx, Entry { labels: option })| do_labels_match(*idx, option, &labels))
         .map(|(idx, _)| idx),
     )
   }
@@ -131,13 +148,16 @@ impl Index {
 
     let mut results = Vec::new();
 
-    for (idx, option) in self.0.iter().enumerate() {
+    for (idx, Entry { labels: option }) in self.entries.iter().enumerate() {
       let mut option_name = String::new();
       for label in option {
-        match label {
-          Label::InPlace(data) => option_name.push_str(data),
-          Label::Reference(reference) => option_name.push_str(self.resolve_reference(reference)?),
-        }
+        option_name.push_str(&String::try_from(
+          match label {
+            Label::InPlace(data) => data,
+            Label::Reference(reference) => self.resolve_reference(reference)?,
+          }
+          .clone(),
+        )?);
         option_name.push('.')
       }
       // remove last dot...
@@ -168,13 +188,16 @@ impl Index {
   pub fn all(&self, max: usize) -> Result<Vec<String>, IxxError> {
     let mut options = Vec::new();
 
-    for option in &self.0[..max] {
+    for Entry { labels: option } in &self.entries[..max] {
       let mut option_name = String::new();
       for label in option {
-        match label {
-          Label::InPlace(data) => option_name.push_str(data),
-          Label::Reference(reference) => option_name.push_str(self.resolve_reference(reference)?),
-        }
+        option_name.push_str(&String::try_from(
+          match label {
+            Label::InPlace(data) => data,
+            Label::Reference(reference) => self.resolve_reference(reference)?,
+          }
+          .clone(),
+        )?);
         option_name.push('.')
       }
       // remove last dot...