diff --git a/bindings/node/native/src/decoders.rs b/bindings/node/native/src/decoders.rs
index 53d36a5b..bc65c37b 100644
--- a/bindings/node/native/src/decoders.rs
+++ b/bindings/node/native/src/decoders.rs
@@ -5,7 +5,7 @@ use neon::prelude::*;
 
 /// Decoder
 pub struct Decoder {
-    pub decoder: Container<dyn tk::tokenizer::Decoder + Sync>,
+    pub decoder: Container<dyn tk::tokenizer::Decoder>,
 }
 
 declare_types! {
diff --git a/bindings/node/native/src/models.rs b/bindings/node/native/src/models.rs
index d03bab26..0800b4e6 100644
--- a/bindings/node/native/src/models.rs
+++ b/bindings/node/native/src/models.rs
@@ -7,7 +7,7 @@ use std::path::Path;
 
 /// Model
 pub struct Model {
-    pub model: Container<dyn tk::tokenizer::Model + Sync>,
+    pub model: Container<dyn tk::tokenizer::Model>,
 }
 
 declare_types! {
diff --git a/bindings/node/native/src/normalizers.rs b/bindings/node/native/src/normalizers.rs
index db3f4dbd..55f4afaf 100644
--- a/bindings/node/native/src/normalizers.rs
+++ b/bindings/node/native/src/normalizers.rs
@@ -5,7 +5,7 @@ use neon::prelude::*;
 
 /// Normalizer
 pub struct Normalizer {
-    pub normalizer: Container<dyn tk::tokenizer::Normalizer + Sync>,
+    pub normalizer: Container<dyn tk::tokenizer::Normalizer>,
 }
 
 declare_types! {
diff --git a/bindings/node/native/src/pre_tokenizers.rs b/bindings/node/native/src/pre_tokenizers.rs
index 54c2e52a..6a8ba252 100644
--- a/bindings/node/native/src/pre_tokenizers.rs
+++ b/bindings/node/native/src/pre_tokenizers.rs
@@ -5,7 +5,7 @@ use neon::prelude::*;
 
 /// PreTokenizers
 pub struct PreTokenizer {
-    pub pretok: Container<dyn tk::tokenizer::PreTokenizer + Sync>,
+    pub pretok: Container<dyn tk::tokenizer::PreTokenizer>,
 }
 
 declare_types! {
diff --git a/bindings/node/native/src/processors.rs b/bindings/node/native/src/processors.rs
index 07db9ff8..7056102b 100644
--- a/bindings/node/native/src/processors.rs
+++ b/bindings/node/native/src/processors.rs
@@ -5,7 +5,7 @@ use neon::prelude::*;
 
 /// Processor
 pub struct Processor {
-    pub processor: Container<dyn tk::tokenizer::PostProcessor + Sync>,
+    pub processor: Container<dyn tk::tokenizer::PostProcessor>,
 }
 
 declare_types! {
diff --git a/bindings/python/src/decoders.rs b/bindings/python/src/decoders.rs
index 215aaff4..82208926 100644
--- a/bindings/python/src/decoders.rs
+++ b/bindings/python/src/decoders.rs
@@ -9,7 +9,7 @@ use tk::tokenizer::Result;
 
 #[pyclass(dict)]
 pub struct Decoder {
-    pub decoder: Container<dyn tk::tokenizer::Decoder + Sync>,
+    pub decoder: Container<dyn tk::tokenizer::Decoder>,
 }
 #[pymethods]
 impl Decoder {
diff --git a/bindings/python/src/models.rs b/bindings/python/src/models.rs
index 53c1b5a0..7beb8b59 100644
--- a/bindings/python/src/models.rs
+++ b/bindings/python/src/models.rs
@@ -78,7 +78,7 @@ impl<'source> FromPyObject<'source> for EncodeInput {
 /// This class cannot be constructed directly. Please use one of the concrete models.
 #[pyclass]
 pub struct Model {
-    pub model: Container<dyn tk::tokenizer::Model + Sync>,
+    pub model: Container<dyn tk::tokenizer::Model>,
 }
 
 #[pymethods]
diff --git a/bindings/python/src/normalizers.rs b/bindings/python/src/normalizers.rs
index fe3c6e6c..723bb407 100644
--- a/bindings/python/src/normalizers.rs
+++ b/bindings/python/src/normalizers.rs
@@ -7,7 +7,7 @@ use pyo3::types::*;
 
 #[pyclass(dict)]
 pub struct Normalizer {
-    pub normalizer: Container<dyn tk::tokenizer::Normalizer + Sync>,
+    pub normalizer: Container<dyn tk::tokenizer::Normalizer>,
 }
 
 #[pyclass(extends=Normalizer)]
diff --git a/bindings/python/src/pre_tokenizers.rs b/bindings/python/src/pre_tokenizers.rs
index af48b0b1..14250065 100644
--- a/bindings/python/src/pre_tokenizers.rs
+++ b/bindings/python/src/pre_tokenizers.rs
@@ -9,7 +9,7 @@ use tk::tokenizer::{Offsets, Result};
 
 #[pyclass(dict)]
 pub struct PreTokenizer {
-    pub pretok: Container<dyn tk::tokenizer::PreTokenizer + Sync>,
+    pub pretok: Container<dyn tk::tokenizer::PreTokenizer>,
 }
 #[pymethods]
 impl PreTokenizer {
diff --git a/bindings/python/src/processors.rs b/bindings/python/src/processors.rs
index 4ef1ab78..0d533f15 100644
--- a/bindings/python/src/processors.rs
+++ b/bindings/python/src/processors.rs
@@ -6,7 +6,7 @@ use pyo3::types::*;
 
 #[pyclass(dict)]
 pub struct PostProcessor {
-    pub processor: Container<dyn tk::tokenizer::PostProcessor + Sync>,
+    pub processor: Container<dyn tk::tokenizer::PostProcessor>,
 }
 
 #[pymethods]
diff --git a/tokenizers/src/models/bpe/trainer.rs b/tokenizers/src/models/bpe/trainer.rs
index 4b942a0e..9e014c31 100644
--- a/tokenizers/src/models/bpe/trainer.rs
+++ b/tokenizers/src/models/bpe/trainer.rs
@@ -601,7 +601,7 @@ impl Trainer for BpeTrainer {
     fn train(
         &self,
         word_counts: HashMap<String, u32>,
-    ) -> Result<(Box<dyn Model + Sync>, Vec<AddedToken>)> {
+    ) -> Result<(Box<dyn Model>, Vec<AddedToken>)> {
         let (bpe, tokens) = self.train(word_counts)?;
         Ok((Box::new(bpe), tokens))
     }
diff --git a/tokenizers/src/models/wordpiece/trainer.rs b/tokenizers/src/models/wordpiece/trainer.rs
index 7363ac8e..a22b2e6d 100644
--- a/tokenizers/src/models/wordpiece/trainer.rs
+++ b/tokenizers/src/models/wordpiece/trainer.rs
@@ -99,7 +99,7 @@ impl Trainer for WordPieceTrainer {
     fn train(
         &self,
         word_counts: HashMap<String, u32>,
-    ) -> Result<(Box<dyn Model + Sync>, Vec<AddedToken>)> {
+    ) -> Result<(Box<dyn Model>, Vec<AddedToken>)> {
         let (wp, tokens) = self.train(word_counts)?;
         Ok((Box::new(wp), tokens))
     }
diff --git a/tokenizers/src/normalizers/utils.rs b/tokenizers/src/normalizers/utils.rs
index b2f16f94..85e5c83c 100644
--- a/tokenizers/src/normalizers/utils.rs
+++ b/tokenizers/src/normalizers/utils.rs
@@ -3,11 +3,11 @@ use crate::tokenizer::{NormalizedString, Normalizer, Result};
 /// Allows concatenating multiple other Normalizer as a Sequence.
 /// All the normalizers run in sequence in the given order against the same NormalizedString.
 pub struct Sequence {
-    normalizers: Vec<Box<dyn Normalizer + Sync>>,
+    normalizers: Vec<Box<dyn Normalizer>>,
 }
 
 impl Sequence {
-    pub fn new(normalizers: Vec<Box<dyn Normalizer + Sync>>) -> Self {
+    pub fn new(normalizers: Vec<Box<dyn Normalizer>>) -> Self {
         Self { normalizers }
     }
 }
diff --git a/tokenizers/src/tokenizer/mod.rs b/tokenizers/src/tokenizer/mod.rs
index d3a6140f..69758984 100644
--- a/tokenizers/src/tokenizer/mod.rs
+++ b/tokenizers/src/tokenizer/mod.rs
@@ -31,7 +31,7 @@ pub type Result<T> = std::result::Result<T, Box<dyn std::error::Error + Send + S
 pub type Offsets = (usize, usize);
 
 /// Takes care of pre-processing strings.
-pub trait Normalizer {
+pub trait Normalizer: Send + Sync {
     fn normalize(&self, normalized: &mut NormalizedString) -> Result<()>;
 }
 
@@ -40,12 +40,12 @@ pub trait Normalizer {
 /// `NormalizedString`. In some occasions, the `PreTokenizer` might need to modify the given
 /// `NormalizedString` to ensure we can entirely keep track of the offsets and the mapping with
 /// the original string.
-pub trait PreTokenizer {
+pub trait PreTokenizer: Send + Sync {
     fn pre_tokenize(&self, normalized: &mut NormalizedString) -> Result<Vec<(String, Offsets)>>;
 }
 
 /// Represents a model used during Tokenization (like BPE or Word or Unigram).
-pub trait Model {
+pub trait Model: Send + Sync {
     fn tokenize(&self, tokens: Vec<(String, Offsets)>) -> Result<Vec<Token>>;
     fn token_to_id(&self, token: &str) -> Option<u32>;
     fn id_to_token(&self, id: u32) -> Option<String>;
@@ -56,7 +56,7 @@ pub trait Model {
 
 /// A `PostProcessor` has the responsibility to post process an encoded output of the `Tokenizer`.
 /// It adds any special tokens that a language model would require.
-pub trait PostProcessor {
+pub trait PostProcessor: Send + Sync {
     /// Returns the number of tokens that will be added during the processing step
     fn added_tokens(&self, is_pair: bool) -> usize;
     /// Process both encodings and returns a new merged one
@@ -84,7 +84,7 @@ impl dyn PostProcessor {
 }
 
 /// A `Decoder` has the responsibility to merge the given `Vec<String>` in a `String`.
-pub trait Decoder {
+pub trait Decoder: Send + Sync {
     fn decode(&self, tokens: Vec<String>) -> Result<String>;
 }
 
@@ -95,10 +95,7 @@ pub trait Trainer: Sync {
     fn should_show_progress(&self) -> bool;
     /// The actual training method. This will return a new trained Model as well as a list
     /// of `special_tokens` to be added directly to the tokenizer along with the model.
-    fn train(
-        &self,
-        words: HashMap<String, u32>,
-    ) -> Result<(Box<dyn Model + Sync>, Vec<AddedToken>)>;
+    fn train(&self, words: HashMap<String, u32>) -> Result<(Box<dyn Model>, Vec<AddedToken>)>;
     /// Process a bunch of token, counting them as relevant.
     fn process_tokens(&self, words: &mut HashMap<String, u32>, tokens: Vec<String>);
 }
@@ -226,11 +223,11 @@ impl std::cmp::Eq for AddedToken {}
 /// A `Tokenizer` is capable of encoding/decoding any text.
 pub struct Tokenizer {
     // Tokenizer parts
-    normalizer: Option<Box<dyn Normalizer + Sync>>,
-    pre_tokenizer: Option<Box<dyn PreTokenizer + Sync>>,
-    model: Box<dyn Model + Sync>,
-    post_processor: Option<Box<dyn PostProcessor + Sync>>,
-    decoder: Option<Box<dyn Decoder + Sync>>,
+    normalizer: Option<Box<dyn Normalizer>>,
+    pre_tokenizer: Option<Box<dyn PreTokenizer>>,
+    model: Box<dyn Model>,
+    post_processor: Option<Box<dyn PostProcessor>>,
+    decoder: Option<Box<dyn Decoder>>,
 
     // Added Vocabulary capabilities
     /// Contains the mapping from String to ID as the user intended it. This map
@@ -256,7 +253,7 @@ pub struct Tokenizer {
 
 impl Tokenizer {
     /// Instanciate a new Tokenizer, with the given Model
-    pub fn new(model: Box<dyn Model + Sync>) -> Self {
+    pub fn new(model: Box<dyn Model>) -> Self {
         Tokenizer {
             normalizer: None,
             pre_tokenizer: None,
@@ -277,62 +274,62 @@ impl Tokenizer {
     }
 
     /// Set the normalizer
-    pub fn with_normalizer(&mut self, normalizer: Box<dyn Normalizer + Sync>) -> &Self {
+    pub fn with_normalizer(&mut self, normalizer: Box<dyn Normalizer>) -> &Self {
         self.normalizer = Some(normalizer);
         self
     }
 
     /// Get the normalizer
     #[allow(clippy::borrowed_box)]
-    pub fn get_normalizer(&self) -> Option<&Box<dyn Normalizer + Sync>> {
+    pub fn get_normalizer(&self) -> Option<&Box<dyn Normalizer>> {
         self.normalizer.as_ref()
     }
 
     /// Set the pre tokenizer
-    pub fn with_pre_tokenizer(&mut self, pre_tokenizer: Box<dyn PreTokenizer + Sync>) -> &Self {
+    pub fn with_pre_tokenizer(&mut self, pre_tokenizer: Box<dyn PreTokenizer>) -> &Self {
         self.pre_tokenizer = Some(pre_tokenizer);
         self
     }
 
     /// Get the pre tokenizer
     #[allow(clippy::borrowed_box)]
-    pub fn get_pre_tokenizer(&self) -> Option<&Box<dyn PreTokenizer + Sync>> {
+    pub fn get_pre_tokenizer(&self) -> Option<&Box<dyn PreTokenizer>> {
         self.pre_tokenizer.as_ref()
     }
 
     /// Set the post processor
-    pub fn with_post_processor(&mut self, post_processor: Box<dyn PostProcessor + Sync>) -> &Self {
+    pub fn with_post_processor(&mut self, post_processor: Box<dyn PostProcessor>) -> &Self {
         self.post_processor = Some(post_processor);
         self
     }
 
     /// Get the post processor
     #[allow(clippy::borrowed_box)]
-    pub fn get_post_processor(&self) -> Option<&Box<dyn PostProcessor + Sync>> {
+    pub fn get_post_processor(&self) -> Option<&Box<dyn PostProcessor>> {
         self.post_processor.as_ref()
     }
 
     /// Set the decoder
-    pub fn with_decoder(&mut self, decoder: Box<dyn Decoder + Sync>) -> &Self {
+    pub fn with_decoder(&mut self, decoder: Box<dyn Decoder>) -> &Self {
         self.decoder = Some(decoder);
         self
     }
 
     /// Get the decoder
     #[allow(clippy::borrowed_box)]
-    pub fn get_decoder(&self) -> Option<&Box<dyn Decoder + Sync>> {
+    pub fn get_decoder(&self) -> Option<&Box<dyn Decoder>> {
         self.decoder.as_ref()
     }
 
     /// Set the model
-    pub fn with_model(&mut self, model: Box<dyn Model + Sync>) -> &Self {
+    pub fn with_model(&mut self, model: Box<dyn Model>) -> &Self {
         self.model = model;
         self
     }
 
     /// Get the model
     #[allow(clippy::borrowed_box)]
-    pub fn get_model(&self) -> &Box<dyn Model + Sync> {
+    pub fn get_model(&self) -> &Box<dyn Model> {
         &self.model
     }