diff --git a/base64ct/src/encoding.rs b/base64ct/src/encoding.rs
index 77b6a90f9..d79728fd0 100644
--- a/base64ct/src/encoding.rs
+++ b/base64ct/src/encoding.rs
@@ -4,7 +4,7 @@ use crate::{
     errors::{Error, InvalidEncodingError, InvalidLengthError},
     variant::Variant,
 };
-use core::str;
+use core::{fmt::Debug, str};
 
 #[cfg(feature = "alloc")]
 use alloc::{string::String, vec::Vec};
@@ -16,7 +16,7 @@ const PAD: u8 = b'=';
 ///
 /// This trait must be imported to make use of any Base64 variant defined
 /// in this crate.
-pub trait Encoding {
+pub trait Encoding: 'static + Copy + Clone + Debug + Send + Sized + Sync {
     /// Decode a Base64 string into the provided destination buffer.
     fn decode(src: impl AsRef<[u8]>, dst: &mut [u8]) -> Result<&[u8], Error>;
 
diff --git a/base64ct/src/variant.rs b/base64ct/src/variant.rs
index 853f1a916..019512e22 100644
--- a/base64ct/src/variant.rs
+++ b/base64ct/src/variant.rs
@@ -1,6 +1,6 @@
 //! Base64 variants
 
-use core::ops::Range;
+use core::{fmt::Debug, ops::Range};
 
 pub mod bcrypt;
 pub mod crypt;
@@ -8,7 +8,7 @@ pub mod standard;
 pub mod url;
 
 /// Core encoder/decoder functions for a particular Base64 variant
-pub trait Variant {
+pub trait Variant: 'static + Copy + Clone + Debug + Send + Sized + Sync {
     /// Unpadded equivalent of this variant.
     ///
     /// For variants that are unpadded to begin with, this should be `Self`.
diff --git a/base64ct/src/variant/bcrypt.rs b/base64ct/src/variant/bcrypt.rs
index 9a8bb622f..80e24bc95 100644
--- a/base64ct/src/variant/bcrypt.rs
+++ b/base64ct/src/variant/bcrypt.rs
@@ -8,6 +8,7 @@ use super::{Decode, Encode, Variant};
 /// ./         [A-Z]      [a-z]     [0-9]
 /// 0x2e-0x2f, 0x41-0x5a, 0x61-0x7a, 0x30-0x39
 /// ```
+#[derive(Copy, Clone, Debug)]
 pub struct Base64Bcrypt;
 
 impl Variant for Base64Bcrypt {
diff --git a/base64ct/src/variant/crypt.rs b/base64ct/src/variant/crypt.rs
index 764fc0a67..5ca9ed50f 100644
--- a/base64ct/src/variant/crypt.rs
+++ b/base64ct/src/variant/crypt.rs
@@ -8,6 +8,7 @@ use super::{Decode, Encode, Variant};
 /// [.-9]      [A-Z]      [a-z]
 /// 0x2e-0x39, 0x41-0x5a, 0x61-0x7a
 /// ```
+#[derive(Copy, Clone, Debug)]
 pub struct Base64Crypt;
 
 impl Variant for Base64Crypt {
diff --git a/base64ct/src/variant/standard.rs b/base64ct/src/variant/standard.rs
index 02ff0d7fb..29ed9cca1 100644
--- a/base64ct/src/variant/standard.rs
+++ b/base64ct/src/variant/standard.rs
@@ -8,6 +8,7 @@ use super::{Decode, Encode, Variant};
 /// [A-Z]      [a-z]      [0-9]      +     /
 /// 0x41-0x5a, 0x61-0x7a, 0x30-0x39, 0x2b, 0x2f
 /// ```
+#[derive(Copy, Clone, Debug)]
 pub struct Base64;
 
 impl Variant for Base64 {
@@ -24,6 +25,7 @@ impl Variant for Base64 {
 /// [A-Z]      [a-z]      [0-9]      +     /
 /// 0x41-0x5a, 0x61-0x7a, 0x30-0x39, 0x2b, 0x2f
 /// ```
+#[derive(Copy, Clone, Debug)]
 pub struct Base64Unpadded;
 
 impl Variant for Base64Unpadded {
diff --git a/base64ct/src/variant/url.rs b/base64ct/src/variant/url.rs
index 47f889e40..3c37abfed 100644
--- a/base64ct/src/variant/url.rs
+++ b/base64ct/src/variant/url.rs
@@ -8,6 +8,7 @@ use super::{Decode, Encode, Variant};
 /// [A-Z]      [a-z]      [0-9]      -     _
 /// 0x41-0x5a, 0x61-0x7a, 0x30-0x39, 0x2d, 0x5f
 /// ```
+#[derive(Copy, Clone, Debug)]
 pub struct Base64Url;
 
 impl Variant for Base64Url {
@@ -24,6 +25,7 @@ impl Variant for Base64Url {
 /// [A-Z]      [a-z]      [0-9]      -     _
 /// 0x41-0x5a, 0x61-0x7a, 0x30-0x39, 0x2d, 0x5f
 /// ```
+#[derive(Copy, Clone, Debug)]
 pub struct Base64UrlUnpadded;
 
 impl Variant for Base64UrlUnpadded {