diff --git a/api/src/accounts.rs b/api/src/accounts.rs
index 03b3c0e271934..5d81cb5910769 100644
--- a/api/src/accounts.rs
+++ b/api/src/accounts.rs
@@ -11,7 +11,7 @@ use crate::{
 
 use aptos_api_types::{
     AccountData, Address, AsConverter, Error, LedgerInfo, MoveModuleBytecode, Response,
-    TransactionId,
+    TransactionId, U64,
 };
 use aptos_types::{
     account_config::AccountResource,
@@ -113,7 +113,7 @@ impl Account {
         if ledger_version > latest_ledger_info.version() {
             return Err(Error::not_found(
                 "ledger",
-                TransactionId::Version(ledger_version),
+                TransactionId::Version(U64::from(ledger_version)),
                 latest_ledger_info.version(),
             ));
         }
diff --git a/api/src/blocks.rs b/api/src/blocks.rs
index 04b381fe196f1..ce9df25c65e3d 100644
--- a/api/src/blocks.rs
+++ b/api/src/blocks.rs
@@ -3,7 +3,7 @@
 
 use crate::{context::Context, failpoint::fail_point, metrics::metrics, param::LedgerVersionParam};
 use anyhow::Result;
-use aptos_api_types::{Error, LedgerInfo, Response, TransactionId};
+use aptos_api_types::{Error, LedgerInfo, Response, TransactionId, U64};
 use warp::{filters::BoxedFilter, Filter, Rejection, Reply};
 
 // GET /blocks/<version>
@@ -43,7 +43,7 @@ impl Block {
         if ledger_version > latest_ledger_info.version() {
             return Err(Error::not_found(
                 "ledger",
-                TransactionId::Version(ledger_version),
+                TransactionId::Version(U64::from(ledger_version)),
                 latest_ledger_info.version(),
             ));
         }
diff --git a/api/src/page.rs b/api/src/page.rs
index d74df462195dd..7e64c683153e3 100644
--- a/api/src/page.rs
+++ b/api/src/page.rs
@@ -3,7 +3,7 @@
 
 use crate::param::{Param, TransactionVersionParam};
 
-use aptos_api_types::{Error, TransactionId};
+use aptos_api_types::{Error, TransactionId, U64};
 
 use anyhow::Result;
 use serde::Deserialize;
@@ -28,7 +28,7 @@ impl Page {
         if version > max {
             return Err(Error::not_found(
                 "transaction",
-                TransactionId::Version(version),
+                TransactionId::Version(U64::from(version)),
                 max,
             ));
         }
diff --git a/api/src/poem_backend/accounts.rs b/api/src/poem_backend/accounts.rs
index f25571d154ea2..e6a9bd4d69ea7 100644
--- a/api/src/poem_backend/accounts.rs
+++ b/api/src/poem_backend/accounts.rs
@@ -10,7 +10,7 @@ use super::{AptosErrorCode, BasicErrorWith404, BasicResultWith404};
 use crate::context::Context;
 use crate::failpoint::fail_point_poem;
 use anyhow::Context as AnyhowContext;
-use aptos_api_types::{AccountData, Address, AsConverter, MoveStructTag, TransactionId};
+use aptos_api_types::{AccountData, Address, AsConverter, MoveStructTag, TransactionId, U64};
 use aptos_api_types::{LedgerInfo, MoveModuleBytecode, MoveResource};
 use aptos_types::access_path::AccessPath;
 use aptos_types::account_config::AccountResource;
@@ -49,7 +49,7 @@ impl AccountsApi {
         &self,
         accept: Accept,
         address: Path<Address>,
-        ledger_version: Query<Option<u64>>,
+        ledger_version: Query<Option<U64>>,
     ) -> BasicResultWith404<AccountData> {
         fail_point_poem("endpoint_get_account")?;
         let accept_type = parse_accept(&accept)?;
@@ -75,7 +75,7 @@ impl AccountsApi {
         &self,
         accept: Accept,
         address: Path<Address>,
-        ledger_version: Query<Option<u64>>,
+        ledger_version: Query<Option<U64>>,
     ) -> BasicResultWith404<Vec<MoveResource>> {
         fail_point_poem("endpoint_get_account_resources")?;
         let accept_type = parse_accept(&accept)?;
@@ -99,7 +99,7 @@ impl AccountsApi {
         &self,
         accept: Accept,
         address: Path<Address>,
-        ledger_version: Query<Option<u64>>,
+        ledger_version: Query<Option<U64>>,
     ) -> BasicResultWith404<Vec<MoveModuleBytecode>> {
         fail_point_poem("endpoint_get_account_modules")?;
         let accept_type = parse_accept(&accept)?;
@@ -119,16 +119,17 @@ impl Account {
     pub fn new(
         context: Arc<Context>,
         address: Address,
-        requested_ledger_version: Option<u64>,
+        requested_ledger_version: Option<U64>,
     ) -> Result<Self, BasicErrorWith404> {
         let latest_ledger_info = context.get_latest_ledger_info_poem()?;
-        let ledger_version: u64 =
-            requested_ledger_version.unwrap_or_else(|| latest_ledger_info.version());
+        let ledger_version: u64 = requested_ledger_version
+            .map(|v| v.0)
+            .unwrap_or_else(|| latest_ledger_info.version());
 
         if ledger_version > latest_ledger_info.version() {
             return Err(build_not_found(
                 "ledger",
-                TransactionId::Version(ledger_version),
+                TransactionId::Version(U64::from(ledger_version)),
                 latest_ledger_info.version(),
             ));
         }
diff --git a/api/src/poem_backend/events.rs b/api/src/poem_backend/events.rs
index 9af4b5ad6c975..197a0b9730dab 100644
--- a/api/src/poem_backend/events.rs
+++ b/api/src/poem_backend/events.rs
@@ -13,7 +13,7 @@ use super::{
 use crate::context::Context;
 use crate::failpoint::fail_point_poem;
 use anyhow::Context as AnyhowContext;
-use aptos_api_types::{Address, EventKey, IdentifierWrapper, MoveStructTagWrapper};
+use aptos_api_types::{Address, EventKey, IdentifierWrapper, MoveStructTagWrapper, U64};
 use aptos_api_types::{AsConverter, Event};
 use poem::web::Accept;
 use poem_openapi::param::Query;
@@ -41,12 +41,12 @@ impl EventsApi {
         // Consider unpacking the inner EventKey type and taking two params, the creation
         // number and the address.
         event_key: Path<EventKey>,
-        start: Query<Option<u64>>,
+        start: Query<Option<U64>>,
         limit: Query<Option<u16>>,
     ) -> BasicResultWith404<Vec<Event>> {
         fail_point_poem("endpoint_get_events_by_event_key")?;
         let accept_type = parse_accept(&accept)?;
-        let page = Page::new(start.0, limit.0);
+        let page = Page::new(start.0.map(|v| v.0), limit.0);
         self.list(&accept_type, page, event_key.0)
     }
 
@@ -67,12 +67,13 @@ impl EventsApi {
         address: Path<Address>,
         event_handle: Path<MoveStructTagWrapper>,
         field_name: Path<IdentifierWrapper>,
-        start: Query<Option<u64>>,
+        start: Query<Option<U64>>,
         limit: Query<Option<u16>>,
     ) -> BasicResultWith404<Vec<Event>> {
+        // TODO: Assert that Event represents u64s as strings.
         fail_point_poem("endpoint_get_events_by_event_handle")?;
         let accept_type = parse_accept(&accept)?;
-        let page = Page::new(start.0, limit.0);
+        let page = Page::new(start.0.map(|v| v.0), limit.0);
         let account = Account::new(self.context.clone(), address.0, None)?;
         let key = account
             .find_event_key(event_handle.0.into(), field_name.0.into())?
diff --git a/api/src/poem_backend/response.rs b/api/src/poem_backend/response.rs
index 1166eb28fe3ea..632a485fbacb9 100644
--- a/api/src/poem_backend/response.rs
+++ b/api/src/poem_backend/response.rs
@@ -237,10 +237,10 @@ macro_rules! generate_success_response {
             $name(
                 $crate::poem_backend::AptosResponseContent<T>,
                 #[oai(header = "X-Aptos-Chain-Id")] u16,
-                #[oai(header = "X-Aptos-Ledger-Version")] u64,
-                #[oai(header = "X-Aptos-Ledger-Oldest-Version")] u64,
-                #[oai(header = "X-Aptos-Ledger-TimestampUsec")] u64,
-                #[oai(header = "X-Aptos-Epoch")] u64,
+                #[oai(header = "X-Aptos-Ledger-Version")] U64,
+                #[oai(header = "X-Aptos-Ledger-Oldest-Version")] U64,
+                #[oai(header = "X-Aptos-Ledger-TimestampUsec")] U64,
+                #[oai(header = "X-Aptos-Epoch")] U64,
             ),
             )*
         }
@@ -274,9 +274,9 @@ macro_rules! generate_success_response {
                         $enum_name::$name(
                             value,
                             ledger_info.chain_id as u16,
-                            ledger_info.ledger_version.into(),
-                            ledger_info.oldest_ledger_version.into(),
-                            ledger_info.ledger_timestamp.into(),
+                            ledger_info.ledger_version,
+                            ledger_info.oldest_ledger_version,
+                            ledger_info.ledger_timestamp,
                             ledger_info.epoch,
                         )
                     },
diff --git a/api/src/poem_backend/state.rs b/api/src/poem_backend/state.rs
index 3f3676bff1cf6..a05d0149cbaff 100644
--- a/api/src/poem_backend/state.rs
+++ b/api/src/poem_backend/state.rs
@@ -12,7 +12,7 @@ use crate::failpoint::fail_point_poem;
 use anyhow::Context as AnyhowContext;
 use aptos_api_types::{
     Address, AsConverter, IdentifierWrapper, MoveModuleBytecode, MoveStructTag,
-    MoveStructTagWrapper, MoveValue, TableItemRequest, TransactionId, U128,
+    MoveStructTagWrapper, MoveValue, TableItemRequest, TransactionId, U128, U64,
 };
 use aptos_api_types::{LedgerInfo, MoveResource};
 use aptos_state_view::StateView;
@@ -55,7 +55,7 @@ impl StateApi {
         accept: Accept,
         address: Path<Address>,
         resource_type: Path<MoveStructTagWrapper>,
-        ledger_version: Query<Option<u64>>,
+        ledger_version: Query<Option<U64>>,
     ) -> BasicResultWith404<MoveResource> {
         fail_point_poem("endpoint_get_account_resource")?;
         let accept_type = parse_accept(&accept)?;
@@ -82,7 +82,7 @@ impl StateApi {
         accept: Accept,
         address: Path<Address>,
         module_name: Path<IdentifierWrapper>,
-        ledger_version: Query<Option<u64>>,
+        ledger_version: Query<Option<U64>>,
     ) -> BasicResultWith404<MoveModuleBytecode> {
         fail_point_poem("endpoint_get_account_module")?;
         let accept_type = parse_accept(&accept)?;
@@ -102,17 +102,16 @@ impl StateApi {
     async fn get_table_item(
         &self,
         accept: Accept,
-        // TODO: Cut over to u128 or U128 once https://github.com/poem-web/poem/pull/336 lands.
         table_handle: Path<U128>,
         table_item_request: Json<TableItemRequest>,
-        ledger_version: Query<Option<u64>>,
+        ledger_version: Query<Option<U64>>,
     ) -> BasicResultWith404<MoveValue> {
         // TODO: fail_point could just be middleware.
         fail_point_poem("endpoint_get_table_item")?;
         let accept_type = parse_accept(&accept)?;
         self.table_item(
             &accept_type,
-            table_handle.0.into(),
+            table_handle.0,
             table_item_request.0,
             ledger_version.0,
         )
@@ -122,16 +121,17 @@ impl StateApi {
 impl StateApi {
     fn preprocess_request<E: NotFoundError + InternalError>(
         &self,
-        requested_ledger_version: Option<u64>,
+        requested_ledger_version: Option<U64>,
     ) -> Result<(LedgerInfo, u64, DbStateView), E> {
         let latest_ledger_info = self.context.get_latest_ledger_info_poem()?;
-        let ledger_version: u64 =
-            requested_ledger_version.unwrap_or_else(|| latest_ledger_info.version());
+        let ledger_version: u64 = requested_ledger_version
+            .map(|v| v.0)
+            .unwrap_or_else(|| latest_ledger_info.version());
 
         if ledger_version > latest_ledger_info.version() {
             return Err(build_not_found(
                 "ledger",
-                TransactionId::Version(ledger_version),
+                TransactionId::Version(U64::from(ledger_version)),
                 latest_ledger_info.version(),
             ));
         }
@@ -148,7 +148,7 @@ impl StateApi {
         accept_type: &AcceptType,
         address: Address,
         resource_type: MoveStructTagWrapper,
-        ledger_version: Option<u64>,
+        ledger_version: Option<U64>,
     ) -> BasicResultWith404<MoveResource> {
         let resource_type: MoveStructTag = resource_type.into();
         let resource_type: StructTag = resource_type
@@ -185,7 +185,7 @@ impl StateApi {
         accept_type: &AcceptType,
         address: Address,
         name: IdentifierWrapper,
-        ledger_version: Option<u64>,
+        ledger_version: Option<U64>,
     ) -> BasicResultWith404<MoveModuleBytecode> {
         let module_id = ModuleId::new(address.into(), name.into());
         let access_path = AccessPath::code_access_path(module_id.clone());
@@ -213,9 +213,9 @@ impl StateApi {
     pub fn table_item(
         &self,
         accept_type: &AcceptType,
-        table_handle: u128,
+        table_handle: U128,
         table_item_request: TableItemRequest,
-        ledger_version: Option<u64>,
+        ledger_version: Option<U64>,
     ) -> BasicResultWith404<MoveValue> {
         let key_type = table_item_request
             .key_type
@@ -242,7 +242,7 @@ impl StateApi {
             .simple_serialize()
             .ok_or_else(|| BasicErrorWith404::internal_str("Failed to serialize table key"))?;
 
-        let state_key = StateKey::table_item(TableHandle(table_handle), raw_key);
+        let state_key = StateKey::table_item(TableHandle(table_handle.0), raw_key);
         let bytes = state_view
             .get_state_value(&state_key)
             .context(format!(
diff --git a/api/src/poem_backend/transactions.rs b/api/src/poem_backend/transactions.rs
index 5a8ae4146971c..7feda70f94e79 100644
--- a/api/src/poem_backend/transactions.rs
+++ b/api/src/poem_backend/transactions.rs
@@ -86,12 +86,12 @@ impl TransactionsApi {
     async fn get_transactions(
         &self,
         accept: Accept,
-        start: Query<Option<u64>>,
+        start: Query<Option<U64>>,
         limit: Query<Option<u16>>,
     ) -> BasicResultWith404<Vec<Transaction>> {
         fail_point_poem("endppoint_get_transactions")?;
         let accept_type = parse_accept(&accept)?;
-        let page = Page::new(start.0, limit.0);
+        let page = Page::new(start.0.map(|v| v.0), limit.0);
         self.list(&accept_type, page)
     }
 
@@ -152,12 +152,12 @@ impl TransactionsApi {
         &self,
         accept: Accept,
         address: Path<Address>,
-        start: Query<Option<u64>>,
+        start: Query<Option<U64>>,
         limit: Query<Option<u16>>,
     ) -> BasicResultWith404<Vec<Transaction>> {
         fail_point_poem("endpoint_get_accounts_transactions")?;
         let accept_type = parse_accept(&accept)?;
-        let page = Page::new(start.0, limit.0);
+        let page = Page::new(start.0.map(|v| v.0), limit.0);
         self.list_by_account(&accept_type, page, address.0)
     }
 
diff --git a/api/src/state.rs b/api/src/state.rs
index 2037cb473adda..ab1f543a66fa4 100644
--- a/api/src/state.rs
+++ b/api/src/state.rs
@@ -13,6 +13,7 @@ use crate::{
 use anyhow::anyhow;
 use aptos_api_types::{
     AsConverter, Error, LedgerInfo, MoveModuleBytecode, Response, TableItemRequest, TransactionId,
+    U64,
 };
 use aptos_state_view::StateView;
 use aptos_types::state_store::table::TableHandle;
@@ -131,7 +132,7 @@ impl State {
         if ledger_version > latest_ledger_info.version() {
             return Err(Error::not_found(
                 "ledger",
-                TransactionId::Version(ledger_version),
+                TransactionId::Version(U64::from(ledger_version)),
                 latest_ledger_info.version(),
             ));
         }
diff --git a/api/src/transactions.rs b/api/src/transactions.rs
index 06c9f26919a38..3d269b7840769 100644
--- a/api/src/transactions.rs
+++ b/api/src/transactions.rs
@@ -428,7 +428,7 @@ impl Transactions {
     ) -> Result<impl Reply, Error> {
         let txn_data = match id.clone() {
             TransactionId::Hash(hash) => self.get_by_hash(hash.into()).await?,
-            TransactionId::Version(version) => self.get_by_version(version)?,
+            TransactionId::Version(version) => self.get_by_version(version.0)?,
         }
         .ok_or_else(|| self.transaction_not_found(id))?;
 
diff --git a/api/types/src/block.rs b/api/types/src/block.rs
index 99d0ecfb2ab7f..7478a33c64960 100644
--- a/api/types/src/block.rs
+++ b/api/types/src/block.rs
@@ -4,6 +4,9 @@
 use crate::HashValue;
 use serde::{Deserialize, Serialize};
 
+// TODO: Consider including this in the API.
+// If we do that, change these u64s to U64.
+
 /// A description of a block
 #[derive(Debug, Copy, Clone, Serialize, Deserialize)]
 pub struct BlockInfo {
diff --git a/api/types/src/ledger_info.rs b/api/types/src/ledger_info.rs
index 7a2e43dcc1daa..4206e3b7380f0 100644
--- a/api/types/src/ledger_info.rs
+++ b/api/types/src/ledger_info.rs
@@ -11,7 +11,7 @@ use serde::{Deserialize, Serialize};
 #[derive(Clone, Debug, Deserialize, Serialize, PartialEq, PoemObject)]
 pub struct LedgerInfo {
     pub chain_id: u8,
-    pub epoch: u64,
+    pub epoch: U64,
     pub ledger_version: U64,
     pub oldest_ledger_version: U64,
     pub ledger_timestamp: U64,
@@ -26,13 +26,17 @@ impl LedgerInfo {
         let ledger_info = info.ledger_info();
         Self {
             chain_id: chain_id.id(),
-            epoch: ledger_info.epoch(),
+            epoch: U64::from(ledger_info.epoch()),
             ledger_version: ledger_info.version().into(),
             oldest_ledger_version: oldest_ledger_version.into(),
             ledger_timestamp: ledger_info.timestamp_usecs().into(),
         }
     }
 
+    pub fn epoch(&self) -> u64 {
+        self.epoch.into()
+    }
+
     pub fn version(&self) -> u64 {
         self.ledger_version.into()
     }
diff --git a/api/types/src/move_types.rs b/api/types/src/move_types.rs
index c85aa2a77277e..493ba91cfa372 100644
--- a/api/types/src/move_types.rs
+++ b/api/types/src/move_types.rs
@@ -23,7 +23,7 @@ use move_deps::{
     move_resource_viewer::{AnnotatedMoveStruct, AnnotatedMoveValue},
 };
 
-use poem_openapi::{Enum, NewType, Object};
+use poem_openapi::{Enum, Object};
 use serde::{de::Error as _, Deserialize, Deserializer, Serialize, Serializer};
 use std::{
     collections::BTreeMap,
@@ -52,7 +52,7 @@ impl TryFrom<AnnotatedMoveStruct> for MoveResource {
     }
 }
 
-#[derive(Clone, Debug, Default, Eq, PartialEq, Copy, NewType)]
+#[derive(Clone, Debug, Default, Eq, PartialEq, Copy)]
 pub struct U64(pub u64);
 
 impl U64 {
@@ -67,18 +67,6 @@ impl From<u64> for U64 {
     }
 }
 
-impl FromStr for U64 {
-    type Err = anyhow::Error;
-
-    fn from_str(s: &str) -> Result<Self, Self::Err> {
-        let data = s
-            .parse::<u64>()
-            .map_err(|e| format_err!("parse u64 string {:?} failed, caused by error: {}", s, e))?;
-
-        Ok(U64(data))
-    }
-}
-
 impl From<U64> for warp::http::header::HeaderValue {
     fn from(d: U64) -> Self {
         d.0.into()
@@ -119,8 +107,20 @@ impl<'de> Deserialize<'de> for U64 {
     }
 }
 
+impl FromStr for U64 {
+    type Err = anyhow::Error;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        let data = s.parse::<u64>().map_err(|e| {
+            format_err!("Parsing u64 string {:?} failed, caused by error: {}", s, e)
+        })?;
+
+        Ok(U64(data))
+    }
+}
+
 #[derive(Clone, Debug, Default, PartialEq, Copy)]
-pub struct U128(u128);
+pub struct U128(pub u128);
 
 impl U128 {
     pub fn inner(&self) -> &u128 {
@@ -168,9 +168,9 @@ impl FromStr for U128 {
     type Err = anyhow::Error;
 
     fn from_str(s: &str) -> Result<Self, Self::Err> {
-        let data = s
-            .parse::<u128>()
-            .map_err(|e| format_err!("parse u128 string {:?} failed, caused by error: {}", s, e))?;
+        let data = s.parse::<u128>().map_err(|e| {
+            format_err!("Parsing u128 string {:?} failed, caused by error: {}", s, e)
+        })?;
 
         Ok(U128(data))
     }
@@ -1334,6 +1334,7 @@ impl_poem_type!(
     MoveType,
     HexEncodedBytes,
     MoveValue,
+    U64,
     U128
 );
-impl_poem_parameter!(HexEncodedBytes, U128);
+impl_poem_parameter!(HexEncodedBytes, U64, U128);
diff --git a/api/types/src/transaction.rs b/api/types/src/transaction.rs
index f7c9dbc619a3f..b8e4e973f77fa 100755
--- a/api/types/src/transaction.rs
+++ b/api/types/src/transaction.rs
@@ -861,7 +861,7 @@ impl From<TransactionAuthenticator> for TransactionSignature {
 #[oai(one_of)]
 pub enum TransactionId {
     Hash(HashValue),
-    Version(u64),
+    Version(U64),
 }
 
 impl FromStr for TransactionId {
@@ -869,7 +869,7 @@ impl FromStr for TransactionId {
 
     fn from_str(hash_or_version: &str) -> Result<Self, anyhow::Error> {
         let id = match hash_or_version.parse::<u64>() {
-            Ok(version) => TransactionId::Version(version),
+            Ok(version) => TransactionId::Version(U64::from(version)),
             Err(_) => TransactionId::Hash(hash_or_version.parse()?),
         };
         Ok(id)
diff --git a/crates/aptos-faucet/src/main.rs b/crates/aptos-faucet/src/main.rs
index 0b6c4b8a724f2..83be1f43e3802 100644
--- a/crates/aptos-faucet/src/main.rs
+++ b/crates/aptos-faucet/src/main.rs
@@ -224,7 +224,7 @@ mod tests {
     fn response<T: Serialize>(body: &T) -> warp::reply::Response {
         let li = LedgerInfo {
             chain_id: ChainId::test().id(),
-            epoch: 1,
+            epoch: 1.into(),
             ledger_version: 5.into(),
             oldest_ledger_version: 0.into(),
             ledger_timestamp: 5.into(),
diff --git a/crates/aptos-rest-client/src/lib.rs b/crates/aptos-rest-client/src/lib.rs
index 87aaac9891e94..61dfefaba32e4 100644
--- a/crates/aptos-rest-client/src/lib.rs
+++ b/crates/aptos-rest-client/src/lib.rs
@@ -80,6 +80,7 @@ impl Client {
         #[derive(Deserialize)]
         struct Response {
             chain_id: u8,
+            #[serde(deserialize_with = "types::deserialize_from_string")]
             epoch: u64,
             #[serde(deserialize_with = "types::deserialize_from_string")]
             ledger_version: u64,