diff --git a/pallas-primitives/Cargo.toml b/pallas-primitives/Cargo.toml
index 13e098e..7e15377 100644
--- a/pallas-primitives/Cargo.toml
+++ b/pallas-primitives/Cargo.toml
@@ -20,3 +20,9 @@ pallas-crypto = { version = "0.8.0", path = "../pallas-crypto" }
 pallas-codec = { version = "0.8.0", path = "../pallas-codec" }
 base58 = "0.2.0"
 bech32 = "0.8.1"
+serde = { version ="1.0.136", optional = true }
+serde_json = { version ="1.0.79", optional = true }
+
+[features]
+json = ["serde", "serde_json"]
+default = ["json"]
\ No newline at end of file
diff --git a/pallas-primitives/src/alonzo/crypto.rs b/pallas-primitives/src/alonzo/crypto.rs
index f07424b..bf1c548 100644
--- a/pallas-primitives/src/alonzo/crypto.rs
+++ b/pallas-primitives/src/alonzo/crypto.rs
@@ -1,4 +1,4 @@
-use super::{AuxiliaryData, Header, PlutusData, TransactionBody};
+use super::{AuxiliaryData, Header, NativeScript, PlutusData, TransactionBody};
 use pallas_crypto::hash::{Hash, Hasher};
 
 pub fn hash_block_header(data: &Header) -> Hash<32> {
@@ -14,10 +14,23 @@ pub fn hash_transaction(data: &TransactionBody) -> Hash<32> {
     Hasher::<256>::hash_cbor(data)
 }
 
+#[deprecated(note = "use PlutusData::to_hash instead")]
 pub fn hash_plutus_data(data: &PlutusData) -> Hash<32> {
     Hasher::<256>::hash_cbor(data)
 }
 
+impl NativeScript {
+    pub fn to_hash(&self) -> Hash<28> {
+        Hasher::<224>::hash_cbor(self)
+    }
+}
+
+impl PlutusData {
+    pub fn to_hash(&self) -> Hash<32> {
+        Hasher::<256>::hash_cbor(self)
+    }
+}
+
 impl TransactionBody {
     pub fn to_hash(&self) -> Hash<32> {
         Hasher::<256>::hash_cbor(self)
diff --git a/pallas-primitives/src/alonzo/json.rs b/pallas-primitives/src/alonzo/json.rs
new file mode 100644
index 0000000..4b8dcab
--- /dev/null
+++ b/pallas-primitives/src/alonzo/json.rs
@@ -0,0 +1,134 @@
+use serde_json::json;
+
+use crate::ToCanonicalJson;
+
+// infered from https://github.com/input-output-hk/cardano-node/blob/c1efb2f97134c0607c982246a36e3da7266ac194/cardano-api/src/Cardano/Api/ScriptData.hs#L254
+impl ToCanonicalJson for super::PlutusData {
+    fn to_json(&self) -> serde_json::Value {
+        match self {
+            super::PlutusData::Constr(x) => {
+                let constructor = x.prefix.map(|x| x as u64).unwrap_or(x.tag);
+                let fields: Vec<_> = x.values.iter().map(|i| i.to_json()).collect();
+                json!({ "constructor": constructor, "fields": fields })
+            }
+            super::PlutusData::Map(x) => {
+                let map: Vec<_> = x
+                    .iter()
+                    .map(|(k, v)| json!({ "k": k.to_json(), "v": v.to_json() }))
+                    .collect();
+                json!({ "map": map })
+            }
+            super::PlutusData::BigInt(int) => match int {
+                super::BigInt::Int(n) => match i64::try_from(*n) {
+                    Ok(x) => json!({ "int": x }),
+                    Err(_) => json!({ "bignint": hex::encode(i128::from(*n).to_be_bytes()) }),
+                },
+                // WARNING / TODO: the CDDL shows a bignum variants of arbitrary length expressed as
+                // bytes, but I can't find the corresponding mapping to JSON in the
+                // Haskell implementation. Not sure what I'm missing. For the time
+                // being, I'll invent a new JSON expression that uses hex strings as
+                // a way to express the values.
+                super::BigInt::BigUInt(x) => json!({ "biguint": hex::encode(x.as_slice())}),
+                super::BigInt::BigNInt(x) => json!({ "bignint": hex::encode(x.as_slice())}),
+            },
+            super::PlutusData::BoundedBytes(x) => json!({ "bytes": hex::encode(x.as_slice())}),
+            super::PlutusData::Array(x) => {
+                let list: Vec<_> = x.iter().map(|i| i.to_json()).collect();
+                json!({ "list": list })
+            }
+            super::PlutusData::ArrayIndef(x) => {
+                let list: Vec<_> = x.iter().map(|i| i.to_json()).collect();
+                json!({ "list": list })
+            }
+        }
+    }
+}
+
+impl ToCanonicalJson for super::NativeScript {
+    fn to_json(&self) -> serde_json::Value {
+        match self {
+            super::NativeScript::ScriptPubkey(x) => {
+                json!({ "keyHash": x.to_string(), "type": "sig"})
+            }
+            super::NativeScript::ScriptAll(x) => {
+                let scripts: Vec<_> = x.iter().map(|i| i.to_json()).collect();
+                json!({ "type": "all", "scripts": scripts})
+            }
+            super::NativeScript::ScriptAny(x) => {
+                let scripts: Vec<_> = x.iter().map(|i| i.to_json()).collect();
+                json!({ "type": "any", "scripts": scripts})
+            }
+            super::NativeScript::ScriptNOfK(n, k) => {
+                let scripts: Vec<_> = k.iter().map(|i| i.to_json()).collect();
+                json!({ "type": "atLeast", "required": n, "scripts" : scripts })
+            }
+            super::NativeScript::InvalidBefore(slot) => json!({ "type": "before", "slot": slot }),
+            super::NativeScript::InvalidHereafter(slot) => json!({"type": "after", "slot": slot }),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::{alonzo::BlockWrapper, Fragment, ToCanonicalJson};
+
+    #[test]
+    fn test_datums_serialize_as_expected() {
+        let test_blocks = vec![(
+            include_str!("test_data/test9.block"),
+            include_str!("test_data/test9.datums"),
+        )];
+
+        for (idx, (block_str, jsonl_str)) in test_blocks.iter().enumerate() {
+            println!("decoding json block {}", idx + 1);
+
+            let bytes = hex::decode(block_str).expect(&format!("bad block file {}", idx));
+
+            let BlockWrapper(_, block) = BlockWrapper::decode_fragment(&bytes[..])
+                .expect(&format!("error decoding cbor for file {}", idx));
+
+            let mut datums = jsonl_str.lines();
+
+            for ws in block.transaction_witness_sets.iter() {
+                if let Some(pds) = &ws.plutus_data {
+                    for pd in pds.iter() {
+                        let expected: serde_json::Value =
+                            serde_json::from_str(datums.next().unwrap()).unwrap();
+                        let current = pd.to_json();
+                        assert_eq!(current, expected);
+                    }
+                }
+            }
+        }
+    }
+
+    #[test]
+    fn test_native_scripts_serialize_as_expected() {
+        let test_blocks = vec![(
+            include_str!("test_data/test9.block"),
+            include_str!("test_data/test9.native"),
+        )];
+
+        for (idx, (block_str, jsonl_str)) in test_blocks.iter().enumerate() {
+            println!("decoding json block {}", idx + 1);
+
+            let bytes = hex::decode(block_str).expect(&format!("bad block file {}", idx));
+
+            let BlockWrapper(_, block) = BlockWrapper::decode_fragment(&bytes[..])
+                .expect(&format!("error decoding cbor for file {}", idx));
+
+            let mut scripts = jsonl_str.lines();
+
+            for ws in block.transaction_witness_sets.iter() {
+                if let Some(nss) = &ws.native_script {
+                    for ns in nss.iter() {
+                        let expected: serde_json::Value =
+                            serde_json::from_str(scripts.next().unwrap()).unwrap();
+                        let current = ns.to_json();
+                        assert_eq!(current, expected);
+                    }
+                }
+            }
+        }
+    }
+}
diff --git a/pallas-primitives/src/alonzo/mod.rs b/pallas-primitives/src/alonzo/mod.rs
index 9add788..ee21683 100644
--- a/pallas-primitives/src/alonzo/mod.rs
+++ b/pallas-primitives/src/alonzo/mod.rs
@@ -3,4 +3,7 @@ mod model;
 pub mod address;
 pub mod crypto;
 
+#[cfg(feature = "json")]
+pub mod json;
+
 pub use model::*;
diff --git a/pallas-primitives/src/alonzo/test_data/test9.datums b/pallas-primitives/src/alonzo/test_data/test9.datums
new file mode 100644
index 0000000..a55f9f9
--- /dev/null
+++ b/pallas-primitives/src/alonzo/test_data/test9.datums
@@ -0,0 +1,4 @@
+{"constructor":0,"fields":[{"bytes":"11f76aa14dae8aa6ac6578af2287bfc4c8e7a3da566548da747e026c"},{"int":250000000},{"bytes":"c56d4cceb8a8550534968e1bf165137ca41e908d2d780cc1402079bd"},{"bytes":"4368696c6c65644b6f6e6734373636"},{"bytes":"1656abe748903d4610c6db6373f036c8aec1b19ece5c93b6f25b5233"},{"int":30}]}
+{"constructor":0,"fields":[{"bytes":"11f76aa14dae8aa6ac6578af2287bfc4c8e7a3da566548da747e026c"},{"int":190000000},{"bytes":"c56d4cceb8a8550534968e1bf165137ca41e908d2d780cc1402079bd"},{"bytes":"4368696c6c65644b6f6e6734373636"},{"bytes":"1656abe748903d4610c6db6373f036c8aec1b19ece5c93b6f25b5233"},{"int":30}]}
+{"constructor":0,"fields":[{"bytes":"92f5aef1645f377ce472eb092ac8a572f9811d3ab2d5dd39cbe07064"},{"int":380000000},{"bytes":"bff82d31352d9bdfdb49e243ab74af715488631f330b2cf064178f90"},{"bytes":"426c6f636b4f776c734269747479303833"},{"bytes":"68b82dc4fb2d515501728de5bfcb1fd0a47eb3dd628d3340e10afa28"},{"biguint":"00"}]}
+{"constructor":0,"fields":[{"bytes":"92f5aef1645f377ce472eb092ac8a572f9811d3ab2d5dd39cbe07064"},{"int":350000000},{"bytes":"bff82d31352d9bdfdb49e243ab74af715488631f330b2cf064178f90"},{"bytes":"426c6f636b4f776c734269747479303833"},{"bytes":"68b82dc4fb2d515501728de5bfcb1fd0a47eb3dd628d3340e10afa28"},{"biguint":"00"}]}
\ No newline at end of file
diff --git a/pallas-primitives/src/alonzo/test_data/test9.native b/pallas-primitives/src/alonzo/test_data/test9.native
new file mode 100644
index 0000000..53c71b8
--- /dev/null
+++ b/pallas-primitives/src/alonzo/test_data/test9.native
@@ -0,0 +1 @@
+{"scripts":[{"keyHash":"4d04380dcb9fbad5aff8e2f4e19394ef4e5e11b37932838f01984a12","type":"sig"},{"slot":112500819,"type":"after"}],"type":"all"}
diff --git a/pallas-primitives/src/framework.rs b/pallas-primitives/src/framework.rs
index a160855..9c7bffc 100644
--- a/pallas-primitives/src/framework.rs
+++ b/pallas-primitives/src/framework.rs
@@ -23,6 +23,11 @@ where
     }
 }
 
+#[cfg(feature = "json")]
+pub trait ToCanonicalJson {
+    fn to_json(&self) -> serde_json::Value;
+}
+
 #[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord)]
 pub enum Era {
     Byron,