diff --git a/Cargo.lock b/Cargo.lock
index c632674da8..4e85fcc3d5 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3038,6 +3038,7 @@ version = "0.1.0"
 dependencies = [
  "anyhow",
  "bigdecimal",
+ "derive_more",
  "num",
  "primitive-types",
  "serde",
@@ -4221,6 +4222,7 @@ dependencies = [
  "itertools 0.11.0",
  "model",
  "num",
+ "number",
  "observe",
  "prometheus",
  "prometheus-metric-storage",
diff --git a/crates/driver/src/boundary/mempool.rs b/crates/driver/src/boundary/mempool.rs
index a362d9a66a..19871ee16e 100644
--- a/crates/driver/src/boundary/mempool.rs
+++ b/crates/driver/src/boundary/mempool.rs
@@ -6,6 +6,8 @@ use {
     },
     async_trait::async_trait,
     ethcontract::{transaction::TransactionBuilder, transport::DynTransport},
+    number::U256,
+    primitive_types::U256 as RawU256,
     solver::{
         settlement_access_list::AccessListEstimating,
         settlement_submission::{
@@ -30,7 +32,7 @@ pub use {gas_estimation::GasPriceEstimating, solver::settlement_submission::Glob
 #[derive(Debug, Clone)]
 pub struct Config {
     pub min_priority_fee: eth::U256,
-    pub gas_price_cap: eth::U256,
+    pub gas_price_cap: U256,
     pub target_confirm_time: std::time::Duration,
     pub max_confirm_time: std::time::Duration,
     pub retry_interval: std::time::Duration,
@@ -51,7 +53,7 @@ pub enum Kind {
     /// The MEVBlocker private mempool.
     MEVBlocker {
         url: reqwest::Url,
-        max_additional_tip: eth::U256,
+        max_additional_tip: RawU256,
         additional_tip_percentage: f64,
         use_soft_cancellations: bool,
     },
@@ -149,7 +151,7 @@ impl Mempool {
             .transaction_count(solver.address().into(), None)
             .await
             .map_err(anyhow::Error::from)?;
-        let max_fee_per_gas = eth::U256::from(settlement.gas.price.max()).to_f64_lossy();
+        let max_fee_per_gas = RawU256::from(settlement.gas.price.max()).to_f64_lossy();
         let gas_price_estimator = SubmitterGasPriceEstimator {
             inner: self.gas_price_estimator.as_ref(),
             max_fee_per_gas: max_fee_per_gas.min(self.config.gas_price_cap.to_f64_lossy()),
diff --git a/crates/driver/src/domain/competition/auction.rs b/crates/driver/src/domain/competition/auction.rs
index 66ce598f87..b48d12c472 100644
--- a/crates/driver/src/domain/competition/auction.rs
+++ b/crates/driver/src/domain/competition/auction.rs
@@ -12,6 +12,7 @@ use {
     },
     futures::future::{join_all, BoxFuture, FutureExt, Shared},
     itertools::Itertools,
+    number::U256,
     std::{
         collections::{HashMap, HashSet},
         sync::{Arc, Mutex},
@@ -410,8 +411,14 @@ impl From<Price> for eth::U256 {
     }
 }
 
-impl From<eth::U256> for Price {
-    fn from(value: eth::U256) -> Self {
+impl From<Price> for U256 {
+    fn from(value: Price) -> Self {
+        value.0.into()
+    }
+}
+
+impl From<U256> for Price {
+    fn from(value: U256) -> Self {
         Self(value.into())
     }
 }
diff --git a/crates/driver/src/domain/competition/order/mod.rs b/crates/driver/src/domain/competition/order/mod.rs
index f8629f55fe..5a3f3e4339 100644
--- a/crates/driver/src/domain/competition/order/mod.rs
+++ b/crates/driver/src/domain/competition/order/mod.rs
@@ -7,6 +7,7 @@ use {
     },
     bigdecimal::Zero,
     num::CheckedDiv,
+    number::U256,
 };
 pub use {fees::FeePolicy, signature::Signature};
 
@@ -56,6 +57,12 @@ impl From<eth::U256> for SellAmount {
     }
 }
 
+impl From<U256> for SellAmount {
+    fn from(value: U256) -> Self {
+        Self(value.into())
+    }
+}
+
 impl From<eth::TokenAmount> for SellAmount {
     fn from(value: eth::TokenAmount) -> Self {
         Self(value.into())
@@ -68,6 +75,12 @@ impl From<SellAmount> for eth::U256 {
     }
 }
 
+impl From<SellAmount> for U256 {
+    fn from(sell_amount: SellAmount) -> Self {
+        sell_amount.0.into()
+    }
+}
+
 /// An amount denominated in the sell token for [`Side::Sell`] [`Order`]s, or in
 /// the buy token for [`Side::Buy`] [`Order`]s.
 #[derive(Debug, Default, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
@@ -79,6 +92,12 @@ impl From<eth::U256> for TargetAmount {
     }
 }
 
+impl From<U256> for TargetAmount {
+    fn from(value: U256) -> Self {
+        Self(value.into())
+    }
+}
+
 impl From<TargetAmount> for eth::U256 {
     fn from(value: TargetAmount) -> Self {
         value.0
diff --git a/crates/driver/src/domain/competition/score.rs b/crates/driver/src/domain/competition/score.rs
index 72a94d1f8f..79e25ea6f2 100644
--- a/crates/driver/src/domain/competition/score.rs
+++ b/crates/driver/src/domain/competition/score.rs
@@ -1,5 +1,6 @@
 use {
     crate::{boundary, domain::eth},
+    number::U256,
     std::cmp::Ordering,
 };
 
@@ -22,6 +23,14 @@ impl TryFrom<eth::U256> for Score {
     }
 }
 
+impl TryFrom<U256> for Score {
+    type Error = Error;
+
+    fn try_from(value: U256) -> Result<Self, Self::Error> {
+        eth::U256::from(value).try_into()
+    }
+}
+
 /// Represents the observed quality of a solution. It's defined as surplus +
 /// fees.
 #[derive(Debug, Default, PartialEq, Eq, PartialOrd, Ord, Copy, Clone)]
diff --git a/crates/driver/src/domain/eth/gas.rs b/crates/driver/src/domain/eth/gas.rs
index 77c63d855b..e8cda782f0 100644
--- a/crates/driver/src/domain/eth/gas.rs
+++ b/crates/driver/src/domain/eth/gas.rs
@@ -2,6 +2,7 @@ use {
     super::{Ether, U256},
     bigdecimal::Zero,
     num::zero,
+    number::U256 as NumberU256,
     std::{ops, ops::Add},
 };
 
@@ -18,6 +19,12 @@ impl From<U256> for Gas {
     }
 }
 
+impl From<NumberU256> for Gas {
+    fn from(value: NumberU256) -> Self {
+        Self(value.into())
+    }
+}
+
 impl From<u64> for Gas {
     fn from(value: u64) -> Self {
         Self(value.into())
@@ -30,6 +37,12 @@ impl From<Gas> for U256 {
     }
 }
 
+impl From<Gas> for NumberU256 {
+    fn from(value: Gas) -> Self {
+        value.0.into()
+    }
+}
+
 impl Add for Gas {
     type Output = Self;
 
@@ -147,6 +160,12 @@ impl From<U256> for FeePerGas {
     }
 }
 
+impl From<NumberU256> for FeePerGas {
+    fn from(value: NumberU256) -> Self {
+        Self(value.into())
+    }
+}
+
 impl ops::Add<FeePerGas> for FeePerGas {
     type Output = FeePerGas;
 
@@ -161,6 +180,12 @@ impl From<FeePerGas> for U256 {
     }
 }
 
+impl From<FeePerGas> for NumberU256 {
+    fn from(value: FeePerGas) -> Self {
+        value.0.into()
+    }
+}
+
 impl ops::Mul<FeePerGas> for Gas {
     type Output = Ether;
 
@@ -181,12 +206,24 @@ impl From<U256> for EffectiveGasPrice {
     }
 }
 
+impl From<NumberU256> for EffectiveGasPrice {
+    fn from(value: NumberU256) -> Self {
+        Self(value.into())
+    }
+}
+
 impl From<EffectiveGasPrice> for U256 {
     fn from(value: EffectiveGasPrice) -> Self {
         value.0.into()
     }
 }
 
+impl From<EffectiveGasPrice> for NumberU256 {
+    fn from(value: EffectiveGasPrice) -> Self {
+        value.0.into()
+    }
+}
+
 impl Add for EffectiveGasPrice {
     type Output = Self;
 
diff --git a/crates/driver/src/domain/eth/mod.rs b/crates/driver/src/domain/eth/mod.rs
index 86ea183208..5b63f77f15 100644
--- a/crates/driver/src/domain/eth/mod.rs
+++ b/crates/driver/src/domain/eth/mod.rs
@@ -8,6 +8,7 @@ pub mod allowance;
 mod eip712;
 mod gas;
 
+use number::U256 as NumberU256;
 pub use {
     allowance::Allowance,
     eip712::{DomainFields, DomainSeparator},
@@ -201,12 +202,24 @@ impl From<U256> for TokenAmount {
     }
 }
 
+impl From<NumberU256> for TokenAmount {
+    fn from(value: NumberU256) -> Self {
+        Self(value.into())
+    }
+}
+
 impl From<TokenAmount> for U256 {
     fn from(value: TokenAmount) -> Self {
         value.0
     }
 }
 
+impl From<TokenAmount> for NumberU256 {
+    fn from(value: TokenAmount) -> Self {
+        value.0.into()
+    }
+}
+
 impl From<u128> for TokenAmount {
     fn from(value: u128) -> Self {
         Self(value.into())
@@ -271,6 +284,12 @@ impl From<U256> for Ether {
     }
 }
 
+impl From<NumberU256> for Ether {
+    fn from(value: NumberU256) -> Self {
+        Self(value.into())
+    }
+}
+
 impl From<Ether> for num::BigInt {
     fn from(value: Ether) -> Self {
         let mut bytes = [0; 32];
@@ -285,6 +304,12 @@ impl From<Ether> for U256 {
     }
 }
 
+impl From<Ether> for NumberU256 {
+    fn from(value: Ether) -> Self {
+        value.0.into()
+    }
+}
+
 impl From<i32> for Ether {
     fn from(value: i32) -> Self {
         Self(value.into())
diff --git a/crates/driver/src/infra/api/routes/quote/dto/order.rs b/crates/driver/src/infra/api/routes/quote/dto/order.rs
index 6bf7115560..ef80510339 100644
--- a/crates/driver/src/infra/api/routes/quote/dto/order.rs
+++ b/crates/driver/src/infra/api/routes/quote/dto/order.rs
@@ -2,10 +2,9 @@ use {
     crate::{
         domain::{competition, eth, quote, time},
         infra::solver::Timeouts,
-        util::serialize,
     },
+    number::U256,
     serde::Deserialize,
-    serde_with::serde_as,
 };
 
 impl Order {
@@ -23,14 +22,12 @@ impl Order {
     }
 }
 
-#[serde_as]
 #[derive(Debug, Deserialize)]
 #[serde(rename_all = "camelCase", deny_unknown_fields)]
 pub struct Order {
     sell_token: eth::H160,
     buy_token: eth::H160,
-    #[serde_as(as = "serialize::U256")]
-    amount: eth::U256,
+    amount: U256,
     kind: Kind,
     deadline: chrono::DateTime<chrono::Utc>,
 }
diff --git a/crates/driver/src/infra/api/routes/quote/dto/quote.rs b/crates/driver/src/infra/api/routes/quote/dto/quote.rs
index dc72e3729d..9c3ef2ba63 100644
--- a/crates/driver/src/infra/api/routes/quote/dto/quote.rs
+++ b/crates/driver/src/infra/api/routes/quote/dto/quote.rs
@@ -3,6 +3,7 @@ use {
         domain::{eth, quote},
         util::serialize,
     },
+    number::U256,
     serde::Serialize,
     serde_with::serde_as,
 };
@@ -10,7 +11,7 @@ use {
 impl Quote {
     pub fn new(quote: &quote::Quote) -> Self {
         Self {
-            amount: quote.amount,
+            amount: quote.amount.into(),
             interactions: quote
                 .interactions
                 .iter()
@@ -25,12 +26,10 @@ impl Quote {
     }
 }
 
-#[serde_as]
 #[derive(Debug, Serialize)]
 #[serde(rename_all = "camelCase")]
 pub struct Quote {
-    #[serde_as(as = "serialize::U256")]
-    amount: eth::U256,
+    amount: U256,
     interactions: Vec<Interaction>,
     solver: eth::H160,
 }
@@ -40,8 +39,7 @@ pub struct Quote {
 #[serde(rename_all = "camelCase")]
 struct Interaction {
     target: eth::H160,
-    #[serde_as(as = "serialize::U256")]
-    value: eth::U256,
+    value: U256,
     #[serde_as(as = "serialize::Hex")]
     call_data: Vec<u8>,
 }
diff --git a/crates/driver/src/infra/api/routes/solve/dto/auction.rs b/crates/driver/src/infra/api/routes/solve/dto/auction.rs
index f602e79919..888f2e826a 100644
--- a/crates/driver/src/infra/api/routes/solve/dto/auction.rs
+++ b/crates/driver/src/infra/api/routes/solve/dto/auction.rs
@@ -8,6 +8,7 @@ use {
         infra::{solver::Timeouts, tokens, Ethereum},
         util::serialize,
     },
+    number::U256,
     serde::Deserialize,
     serde_with::serde_as,
 };
@@ -200,8 +201,7 @@ pub struct Auction {
     tokens: Vec<Token>,
     orders: Vec<Order>,
     deadline: chrono::DateTime<chrono::Utc>,
-    #[serde_as(as = "serialize::U256")]
-    score_cap: eth::U256,
+    score_cap: U256,
 }
 
 impl Auction {
@@ -210,13 +210,11 @@ impl Auction {
     }
 }
 
-#[serde_as]
 #[derive(Debug, Deserialize)]
 #[serde(rename_all = "camelCase", deny_unknown_fields)]
 struct Token {
     pub address: eth::H160,
-    #[serde_as(as = "Option<serialize::U256>")]
-    pub price: Option<eth::U256>,
+    pub price: Option<U256>,
     pub trusted: bool,
 }
 
@@ -228,12 +226,9 @@ struct Order {
     uid: [u8; order::UID_LEN],
     sell_token: eth::H160,
     buy_token: eth::H160,
-    #[serde_as(as = "serialize::U256")]
-    sell_amount: eth::U256,
-    #[serde_as(as = "serialize::U256")]
-    buy_amount: eth::U256,
-    #[serde_as(as = "serialize::U256")]
-    user_fee: eth::U256,
+    sell_amount: U256,
+    buy_amount: U256,
+    user_fee: U256,
     protocol_fees: Vec<FeePolicy>,
     valid_to: u32,
     kind: Kind,
@@ -241,8 +236,7 @@ struct Order {
     owner: eth::H160,
     partially_fillable: bool,
     /// Always zero if the order is not partially fillable.
-    #[serde_as(as = "serialize::U256")]
-    executed: eth::U256,
+    executed: U256,
     pre_interactions: Vec<Interaction>,
     post_interactions: Vec<Interaction>,
     #[serde(default)]
@@ -269,8 +263,7 @@ enum Kind {
 #[serde(rename_all = "camelCase", deny_unknown_fields)]
 struct Interaction {
     target: eth::H160,
-    #[serde_as(as = "serialize::U256")]
-    value: eth::U256,
+    value: U256,
     #[serde_as(as = "serialize::Hex")]
     call_data: Vec<u8>,
 }
diff --git a/crates/driver/src/infra/api/routes/solve/dto/solved.rs b/crates/driver/src/infra/api/routes/solve/dto/solved.rs
index e6af9b01a0..e10e815d8c 100644
--- a/crates/driver/src/infra/api/routes/solve/dto/solved.rs
+++ b/crates/driver/src/infra/api/routes/solve/dto/solved.rs
@@ -4,6 +4,7 @@ use {
         infra::Solver,
         util::serialize,
     },
+    number::U256,
     serde::Serialize,
     serde_with::serde_as,
     std::collections::HashMap,
@@ -30,7 +31,7 @@ impl Solution {
     pub fn new(solution_id: u64, solved: competition::Solved, solver: &Solver) -> Self {
         Self {
             solution_id,
-            score: solved.score.0.get(),
+            score: solved.score.0.get().into(),
             submission_address: solver.address().into(),
             orders: solved
                 .trades
@@ -54,16 +55,13 @@ impl Solution {
     }
 }
 
-#[serde_as]
 #[derive(Debug, Serialize)]
 #[serde(rename_all = "camelCase")]
 pub struct TradedAmounts {
     /// The effective amount that left the user's wallet including all fees.
-    #[serde_as(as = "serialize::U256")]
-    pub sell_amount: eth::U256,
+    pub sell_amount: U256,
     /// The effective amount the user received after all fees.
-    #[serde_as(as = "serialize::U256")]
-    pub buy_amount: eth::U256,
+    pub buy_amount: U256,
 }
 
 type OrderId = [u8; order::UID_LEN];
@@ -76,11 +74,10 @@ pub struct Solution {
     /// in subsequent requests (reveal, settle).
     #[serde_as(as = "serde_with::DisplayFromStr")]
     solution_id: u64,
-    #[serde_as(as = "serialize::U256")]
-    score: eth::U256,
+    score: U256,
     submission_address: eth::H160,
     #[serde_as(as = "HashMap<serialize::Hex, _>")]
     orders: HashMap<OrderId, TradedAmounts>,
-    #[serde_as(as = "HashMap<_, serialize::U256>")]
-    clearing_prices: HashMap<eth::H160, eth::U256>,
+    #[serde_as(as = "HashMap<_, _>")]
+    clearing_prices: HashMap<eth::H160, U256>,
 }
diff --git a/crates/driver/src/infra/blockchain/gas.rs b/crates/driver/src/infra/blockchain/gas.rs
index d7ea86310b..6330ceee45 100644
--- a/crates/driver/src/infra/blockchain/gas.rs
+++ b/crates/driver/src/infra/blockchain/gas.rs
@@ -57,7 +57,7 @@ impl GasPriceEstimator {
         Ok(Self {
             gas,
             additional_tip,
-            max_fee_per_gas,
+            max_fee_per_gas: max_fee_per_gas.into(),
             min_priority_fee,
         })
     }
diff --git a/crates/driver/src/infra/config/file/load.rs b/crates/driver/src/infra/config/file/load.rs
index f8168a94bf..b0122fa3d9 100644
--- a/crates/driver/src/infra/config/file/load.rs
+++ b/crates/driver/src/infra/config/file/load.rs
@@ -69,7 +69,7 @@ pub async fn load(network: &blockchain::Network, path: &Path) -> infra::Config {
                 name: config.name.into(),
                 slippage: solver::Slippage {
                     relative: config.slippage.relative,
-                    absolute: config.slippage.absolute.map(eth::Ether),
+                    absolute: config.slippage.absolute.map(eth::Ether::from),
                 },
                 liquidity: if config.skip_liquidity {
                     solver::Liquidity::Skip
@@ -254,7 +254,7 @@ pub async fn load(network: &blockchain::Network, path: &Path) -> infra::Config {
             .mempools
             .iter()
             .map(|mempool| mempool::Config {
-                min_priority_fee: config.submission.min_priority_fee,
+                min_priority_fee: config.submission.min_priority_fee.into(),
                 gas_price_cap: config.submission.gas_price_cap,
                 target_confirm_time: config.submission.target_confirm_time,
                 max_confirm_time: config.submission.max_confirm_time,
@@ -284,7 +284,7 @@ pub async fn load(network: &blockchain::Network, path: &Path) -> infra::Config {
                         use_soft_cancellations,
                     } => mempool::Kind::MEVBlocker {
                         url: url.to_owned(),
-                        max_additional_tip: *max_additional_tip,
+                        max_additional_tip: (*max_additional_tip).into(),
                         additional_tip_percentage: *additional_tip_percentage,
                         use_soft_cancellations: *use_soft_cancellations,
                     },
diff --git a/crates/driver/src/infra/config/file/mod.rs b/crates/driver/src/infra/config/file/mod.rs
index 60b2f7ae97..f98b43eea5 100644
--- a/crates/driver/src/infra/config/file/mod.rs
+++ b/crates/driver/src/infra/config/file/mod.rs
@@ -1,6 +1,7 @@
 pub use load::load;
 use {
-    crate::{domain::eth, util::serialize},
+    crate::domain::eth,
+    number::U256,
     reqwest::Url,
     serde::Deserialize,
     serde_with::serde_as,
@@ -10,7 +11,6 @@ use {
 
 mod load;
 
-#[serde_as]
 #[derive(Debug, Deserialize)]
 #[serde(rename_all = "kebab-case", deny_unknown_fields)]
 struct Config {
@@ -18,7 +18,7 @@ struct Config {
     /// Note that the actual chain ID is fetched from the configured Ethereum
     /// RPC endpoint, and the driver will exit if it does not match this
     /// value.
-    chain_id: Option<eth::U256>,
+    chain_id: Option<primitive_types::U256>,
 
     /// Disable access list simulation, useful for environments that don't
     /// support this, such as less popular blockchains.
@@ -28,8 +28,7 @@ struct Config {
     /// Disable gas simulation and always use this fixed gas value instead. This
     /// can be useful for testing, but shouldn't be used in production since it
     /// will cause the driver to return invalid scores.
-    #[serde_as(as = "Option<serialize::U256>")]
-    disable_gas_simulation: Option<eth::U256>,
+    disable_gas_simulation: Option<U256>,
 
     /// Parameters related to settlement submission.
     #[serde(default)]
@@ -52,21 +51,18 @@ struct Config {
     liquidity: LiquidityConfig,
 }
 
-#[serde_as]
 #[derive(Debug, Default, Deserialize)]
 #[serde(rename_all = "kebab-case", deny_unknown_fields)]
 struct SubmissionConfig {
     /// The minimum priority fee in Gwei the solver is ensuring to pay in a
     /// settlement.
     #[serde(default)]
-    #[serde_as(as = "serialize::U256")]
-    min_priority_fee: eth::U256,
+    min_priority_fee: U256,
 
     /// The maximum gas price in Gwei the solver is willing to pay in a
     /// settlement.
     #[serde(default = "default_gas_price_cap")]
-    #[serde_as(as = "serialize::U256")]
-    gas_price_cap: eth::U256,
+    gas_price_cap: U256,
 
     /// The target confirmation time for settlement transactions used
     /// to estimate gas price.
@@ -92,7 +88,6 @@ struct SubmissionConfig {
     logic: Logic,
 }
 
-#[serde_as]
 #[derive(Debug, Deserialize)]
 #[serde(tag = "mempool")]
 #[serde(rename_all = "kebab-case", deny_unknown_fields)]
@@ -105,8 +100,7 @@ enum Mempool {
         /// Maximum additional tip in Gwei that we are willing to give to
         /// MEVBlocker above regular gas price estimation.
         #[serde(default = "default_max_additional_tip")]
-        #[serde_as(as = "serialize::U256")]
-        max_additional_tip: eth::U256,
+        max_additional_tip: U256,
         /// Additional tip in percentage of max_fee_per_gas we are giving to
         /// MEVBlocker above regular gas price estimation. Expects a
         /// floating point value between 0 and 1.
@@ -127,8 +121,8 @@ fn default_additional_tip_percentage() -> f64 {
 }
 
 /// 1000 gwei
-fn default_gas_price_cap() -> eth::U256 {
-    eth::U256::from(1000) * eth::U256::exp10(9)
+fn default_gas_price_cap() -> U256 {
+    U256::from(eth::U256::from(1000) * eth::U256::exp10(9))
 }
 
 fn default_target_confirm_time() -> Duration {
@@ -144,8 +138,8 @@ fn default_max_confirm_time() -> Duration {
 }
 
 /// 3 gwei
-fn default_max_additional_tip() -> eth::U256 {
-    eth::U256::from(3) * eth::U256::exp10(9)
+fn default_max_additional_tip() -> U256 {
+    U256::from(eth::U256::from(3) * eth::U256::exp10(9))
 }
 
 fn default_soft_cancellations_flag() -> bool {
@@ -230,8 +224,7 @@ struct Slippage {
 
     /// The absolute slippage allowed by the solver.
     #[serde(rename = "absolute-slippage")]
-    #[serde_as(as = "Option<serialize::U256>")]
-    absolute: Option<eth::U256>,
+    absolute: Option<U256>,
 }
 
 #[derive(Debug, Default, Deserialize)]
diff --git a/crates/driver/src/infra/solver/dto/auction.rs b/crates/driver/src/infra/solver/dto/auction.rs
index a89491d75a..0917b26df7 100644
--- a/crates/driver/src/infra/solver/dto/auction.rs
+++ b/crates/driver/src/infra/solver/dto/auction.rs
@@ -7,6 +7,7 @@ use {
         },
     },
     indexmap::IndexMap,
+    number::U256,
     serde::Serialize,
     serde_with::serde_as,
     std::collections::{BTreeMap, HashMap},
@@ -28,7 +29,7 @@ impl Auction {
                         decimals: token.decimals,
                         symbol: token.symbol.clone(),
                         reference_price: token.price.map(Into::into),
-                        available_balance: token.available_balance,
+                        available_balance: token.available_balance.into(),
                         trusted: token.trusted,
                     },
                 )
@@ -107,9 +108,9 @@ impl Auction {
                         Liquidity::ConcentratedLiquidity(ConcentratedLiquidityPool {
                             id: liquidity.id.into(),
                             address: pool.address.0,
-                            gas_estimate: liquidity.gas.0,
+                            gas_estimate: liquidity.gas.0.into(),
                             tokens: vec![pool.tokens.get().0.into(), pool.tokens.get().1.into()],
-                            sqrt_price: pool.sqrt_price.0,
+                            sqrt_price: pool.sqrt_price.0.into(),
                             liquidity: pool.liquidity.0,
                             tick: pool.tick.0,
                             liquidity_net: pool
@@ -204,7 +205,6 @@ impl Auction {
     }
 }
 
-#[serde_as]
 #[derive(Debug, Serialize)]
 #[serde(rename_all = "camelCase")]
 pub struct Auction {
@@ -212,8 +212,7 @@ pub struct Auction {
     tokens: HashMap<eth::H160, Token>,
     orders: Vec<Order>,
     liquidity: Vec<Liquidity>,
-    #[serde_as(as = "serialize::U256")]
-    effective_gas_price: eth::U256,
+    effective_gas_price: U256,
     deadline: chrono::DateTime<chrono::Utc>,
 }
 
@@ -225,12 +224,9 @@ struct Order {
     uid: [u8; order::UID_LEN],
     sell_token: eth::H160,
     buy_token: eth::H160,
-    #[serde_as(as = "serialize::U256")]
-    sell_amount: eth::U256,
-    #[serde_as(as = "serialize::U256")]
-    buy_amount: eth::U256,
-    #[serde_as(as = "serialize::U256")]
-    fee_amount: eth::U256,
+    sell_amount: U256,
+    buy_amount: U256,
+    fee_amount: U256,
     kind: Kind,
     partially_fillable: bool,
     class: Class,
@@ -251,16 +247,13 @@ enum Class {
     Liquidity,
 }
 
-#[serde_as]
 #[derive(Default, Debug, Serialize)]
 #[serde(rename_all = "camelCase")]
 struct Token {
     decimals: Option<u8>,
     symbol: Option<String>,
-    #[serde_as(as = "Option<serialize::U256>")]
-    reference_price: Option<eth::U256>,
-    #[serde_as(as = "serialize::U256")]
-    available_balance: eth::U256,
+    reference_price: Option<U256>,
+    available_balance: U256,
     trusted: bool,
 }
 
@@ -283,18 +276,15 @@ struct ConstantProductPool {
     #[serde_as(as = "serde_with::DisplayFromStr")]
     id: usize,
     address: eth::H160,
-    #[serde_as(as = "serialize::U256")]
-    gas_estimate: eth::U256,
+    gas_estimate: U256,
     tokens: BTreeMap<eth::H160, ConstantProductReserve>,
     #[serde_as(as = "serde_with::DisplayFromStr")]
     fee: bigdecimal::BigDecimal,
 }
 
-#[serde_as]
 #[derive(Debug, Serialize)]
 struct ConstantProductReserve {
-    #[serde_as(as = "serialize::U256")]
-    balance: eth::U256,
+    balance: U256,
 }
 
 #[serde_as]
@@ -304,8 +294,7 @@ struct WeightedProductPool {
     #[serde_as(as = "serde_with::DisplayFromStr")]
     id: usize,
     address: eth::H160,
-    #[serde_as(as = "serialize::U256")]
-    gas_estimate: eth::U256,
+    gas_estimate: U256,
     tokens: IndexMap<eth::H160, WeightedProductReserve>,
     #[serde_as(as = "serde_with::DisplayFromStr")]
     fee: bigdecimal::BigDecimal,
@@ -316,8 +305,7 @@ struct WeightedProductPool {
 #[derive(Debug, Serialize)]
 #[serde(rename_all = "camelCase")]
 struct WeightedProductReserve {
-    #[serde_as(as = "serialize::U256")]
-    balance: eth::U256,
+    balance: U256,
     #[serde_as(as = "serde_with::DisplayFromStr")]
     scaling_factor: bigdecimal::BigDecimal,
     #[serde_as(as = "serde_with::DisplayFromStr")]
@@ -338,8 +326,7 @@ struct StablePool {
     #[serde_as(as = "serde_with::DisplayFromStr")]
     id: usize,
     address: eth::H160,
-    #[serde_as(as = "serialize::U256")]
-    gas_estimate: eth::U256,
+    gas_estimate: U256,
     tokens: IndexMap<eth::H160, StableReserve>,
     #[serde_as(as = "serde_with::DisplayFromStr")]
     amplification_parameter: bigdecimal::BigDecimal,
@@ -351,8 +338,7 @@ struct StablePool {
 #[derive(Debug, Serialize)]
 #[serde(rename_all = "camelCase")]
 struct StableReserve {
-    #[serde_as(as = "serialize::U256")]
-    balance: eth::U256,
+    balance: U256,
     #[serde_as(as = "serde_with::DisplayFromStr")]
     scaling_factor: bigdecimal::BigDecimal,
 }
@@ -364,11 +350,9 @@ struct ConcentratedLiquidityPool {
     #[serde_as(as = "serde_with::DisplayFromStr")]
     id: usize,
     address: eth::H160,
-    #[serde_as(as = "serialize::U256")]
-    gas_estimate: eth::U256,
+    gas_estimate: U256,
     tokens: Vec<eth::H160>,
-    #[serde_as(as = "serialize::U256")]
-    sqrt_price: eth::U256,
+    sqrt_price: U256,
     #[serde_as(as = "serde_with::DisplayFromStr")]
     liquidity: u128,
     tick: i32,
@@ -385,18 +369,14 @@ struct ForeignLimitOrder {
     #[serde_as(as = "serde_with::DisplayFromStr")]
     id: usize,
     address: eth::H160,
-    #[serde_as(as = "serialize::U256")]
-    gas_estimate: eth::U256,
+    gas_estimate: U256,
     #[serde_as(as = "serialize::Hex")]
     hash: [u8; 32],
     maker_token: eth::H160,
     taker_token: eth::H160,
-    #[serde_as(as = "serialize::U256")]
-    maker_amount: eth::U256,
-    #[serde_as(as = "serialize::U256")]
-    taker_amount: eth::U256,
-    #[serde_as(as = "serialize::U256")]
-    taker_token_fee_amount: eth::U256,
+    maker_amount: U256,
+    taker_amount: U256,
+    taker_token_fee_amount: U256,
 }
 
 fn fee_to_decimal(fee: liquidity::balancer::v2::Fee) -> bigdecimal::BigDecimal {
diff --git a/crates/driver/src/infra/solver/dto/notification.rs b/crates/driver/src/infra/solver/dto/notification.rs
index b8cb5d1f5c..4fbd3b3b32 100644
--- a/crates/driver/src/infra/solver/dto/notification.rs
+++ b/crates/driver/src/infra/solver/dto/notification.rs
@@ -7,6 +7,7 @@ use {
         infra::notify,
         util::serialize,
     },
+    number::U256,
     serde::Serialize,
     serde_with::serde_as,
     std::collections::BTreeSet,
@@ -43,8 +44,8 @@ impl Notification {
                     score,
                     quality,
                 )) => Kind::ScoreHigherThanQuality {
-                    score: score.0.get(),
-                    quality: quality.0,
+                    score: score.0.get().into(),
+                    quality: quality.0.into(),
                 },
                 notify::Kind::ScoringFailed(notify::ScoreKind::SuccessProbabilityOutOfRange(
                     success_probability,
@@ -55,15 +56,15 @@ impl Notification {
                     quality,
                     gas_cost,
                 )) => Kind::ObjectiveValueNonPositive {
-                    quality: quality.0,
-                    gas_cost: gas_cost.get().0,
+                    quality: quality.0.into(),
+                    gas_cost: gas_cost.get().0.into(),
                 },
                 notify::Kind::NonBufferableTokensUsed(tokens) => Kind::NonBufferableTokensUsed {
                     tokens: tokens.into_iter().map(|token| token.0 .0).collect(),
                 },
                 notify::Kind::SolverAccountInsufficientBalance(required) => {
                     Kind::SolverAccountInsufficientBalance {
-                        required: required.0,
+                        required: required.0.into(),
                     }
                 }
                 notify::Kind::DuplicatedSolutionId => Kind::DuplicatedSolutionId,
@@ -94,7 +95,6 @@ pub struct Notification {
     kind: Kind,
 }
 
-#[serde_as]
 #[derive(Debug, Serialize)]
 #[serde(rename_all = "camelCase", tag = "kind")]
 pub enum Kind {
@@ -109,27 +109,22 @@ pub enum Kind {
     },
     ZeroScore,
     ScoreHigherThanQuality {
-        #[serde_as(as = "serialize::U256")]
-        score: eth::U256,
-        #[serde_as(as = "serialize::U256")]
-        quality: eth::U256,
+        score: U256,
+        quality: U256,
     },
     SuccessProbabilityOutOfRange {
         probability: f64,
     },
     #[serde(rename_all = "camelCase")]
     ObjectiveValueNonPositive {
-        #[serde_as(as = "serialize::U256")]
-        quality: eth::U256,
-        #[serde_as(as = "serialize::U256")]
-        gas_cost: eth::U256,
+        quality: U256,
+        gas_cost: U256,
     },
     NonBufferableTokensUsed {
         tokens: BTreeSet<eth::H160>,
     },
     SolverAccountInsufficientBalance {
-        #[serde_as(as = "serialize::U256")]
-        required: eth::U256,
+        required: U256,
     },
     Success {
         transaction: eth::H256,
@@ -155,7 +150,6 @@ pub struct Tx {
     pub to: eth::H160,
     #[serde_as(as = "serialize::Hex")]
     pub input: Vec<u8>,
-    #[serde_as(as = "serialize::U256")]
-    pub value: eth::U256,
+    pub value: U256,
     pub access_list: AccessList,
 }
diff --git a/crates/driver/src/infra/solver/dto/solution.rs b/crates/driver/src/infra/solver/dto/solution.rs
index 2ed5bc3772..0445ba177e 100644
--- a/crates/driver/src/infra/solver/dto/solution.rs
+++ b/crates/driver/src/infra/solver/dto/solution.rs
@@ -5,6 +5,7 @@ use {
         util::serialize,
     },
     itertools::Itertools,
+    number::U256,
     serde::Deserialize,
     serde_with::serde_as,
     std::collections::HashMap,
@@ -43,7 +44,7 @@ impl Solutions {
                                     fulfillment.executed_amount.into(),
                                     match fulfillment.fee {
                                         Some(fee) => competition::solution::trade::Fee::Dynamic(
-                                            competition::order::SellAmount(fee),
+                                            competition::order::SellAmount(fee.into()),
                                         ),
                                         None => competition::solution::trade::Fee::Static,
                                     },
@@ -118,7 +119,7 @@ impl Solutions {
                     solution
                         .prices
                         .into_iter()
-                        .map(|(address, price)| (address.into(), price))
+                        .map(|(address, price)| (address.into(), price.into()))
                         .collect(),
                     solution
                         .interactions
@@ -137,7 +138,7 @@ impl Solutions {
                                                 eth::Allowance {
                                                     token: allowance.token.into(),
                                                     spender: allowance.spender.into(),
-                                                    amount: allowance.amount,
+                                                    amount: allowance.amount.into(),
                                                 }
                                                 .into()
                                             })
@@ -190,7 +191,7 @@ impl Solutions {
                     solver.clone(),
                     match solution.score {
                         Score::Solver { score } => {
-                            competition::solution::SolverScore::Solver(score)
+                            competition::solution::SolverScore::Solver(score.into())
                         }
                         Score::RiskAdjusted {
                             success_probability,
@@ -223,8 +224,8 @@ pub struct Solutions {
 #[serde(rename_all = "camelCase", deny_unknown_fields)]
 pub struct Solution {
     id: u64,
-    #[serde_as(as = "HashMap<_, serialize::U256>")]
-    prices: HashMap<eth::H160, eth::U256>,
+    #[serde_as(as = "HashMap<_, _>")]
+    prices: HashMap<eth::H160, U256>,
     trades: Vec<Trade>,
     interactions: Vec<Interaction>,
     score: Score,
@@ -243,19 +244,15 @@ enum Trade {
 struct Fulfillment {
     #[serde_as(as = "serialize::Hex")]
     order: [u8; order::UID_LEN],
-    #[serde_as(as = "serialize::U256")]
-    executed_amount: eth::U256,
-    #[serde_as(as = "Option<serialize::U256>")]
-    fee: Option<eth::U256>,
+    executed_amount: U256,
+    fee: Option<U256>,
 }
 
-#[serde_as]
 #[derive(Debug, Deserialize)]
 #[serde(rename_all = "camelCase", deny_unknown_fields)]
 struct JitTrade {
     order: JitOrder,
-    #[serde_as(as = "serialize::U256")]
-    executed_amount: eth::U256,
+    executed_amount: U256,
 }
 
 #[serde_as]
@@ -265,15 +262,12 @@ struct JitOrder {
     sell_token: eth::H160,
     buy_token: eth::H160,
     receiver: eth::H160,
-    #[serde_as(as = "serialize::U256")]
-    sell_amount: eth::U256,
-    #[serde_as(as = "serialize::U256")]
-    buy_amount: eth::U256,
+    sell_amount: U256,
+    buy_amount: U256,
     valid_to: u32,
     #[serde_as(as = "serialize::Hex")]
     app_data: [u8; order::APP_DATA_LEN],
-    #[serde_as(as = "serialize::U256")]
-    fee_amount: eth::U256,
+    fee_amount: U256,
     kind: Kind,
     partially_fillable: bool,
     sell_token_balance: SellTokenBalance,
@@ -306,10 +300,8 @@ struct LiquidityInteraction {
     id: usize,
     input_token: eth::H160,
     output_token: eth::H160,
-    #[serde_as(as = "serialize::U256")]
-    input_amount: eth::U256,
-    #[serde_as(as = "serialize::U256")]
-    output_amount: eth::U256,
+    input_amount: U256,
+    output_amount: U256,
 }
 
 #[serde_as]
@@ -318,8 +310,7 @@ struct LiquidityInteraction {
 struct CustomInteraction {
     internalize: bool,
     target: eth::H160,
-    #[serde_as(as = "serialize::U256")]
-    value: eth::U256,
+    value: U256,
     #[serde_as(as = "serialize::Hex")]
     call_data: Vec<u8>,
     allowances: Vec<Allowance>,
@@ -327,23 +318,19 @@ struct CustomInteraction {
     outputs: Vec<Asset>,
 }
 
-#[serde_as]
 #[derive(Debug, Deserialize)]
 #[serde(rename_all = "camelCase", deny_unknown_fields)]
 struct Asset {
     token: eth::H160,
-    #[serde_as(as = "serialize::U256")]
-    amount: eth::U256,
+    amount: U256,
 }
 
-#[serde_as]
 #[derive(Debug, Deserialize)]
 #[serde(rename_all = "camelCase", deny_unknown_fields)]
 struct Allowance {
     token: eth::H160,
     spender: eth::H160,
-    #[serde_as(as = "serialize::U256")]
-    amount: eth::U256,
+    amount: U256,
 }
 
 #[derive(Debug, Default, Deserialize)]
@@ -372,14 +359,14 @@ enum SigningScheme {
     Eip1271,
 }
 
-#[serde_as]
 #[derive(Debug, Deserialize)]
 #[serde(rename_all = "camelCase", deny_unknown_fields, tag = "kind")]
 pub enum Score {
     Solver {
-        #[serde_as(as = "serialize::U256")]
-        score: eth::U256,
+        score: U256,
     },
     #[serde(rename_all = "camelCase")]
-    RiskAdjusted { success_probability: f64 },
+    RiskAdjusted {
+        success_probability: f64,
+    },
 }
diff --git a/crates/driver/src/tests/setup/mod.rs b/crates/driver/src/tests/setup/mod.rs
index ac97b81a7d..681abd001b 100644
--- a/crates/driver/src/tests/setup/mod.rs
+++ b/crates/driver/src/tests/setup/mod.rs
@@ -23,14 +23,14 @@ use {
             },
             setup::blockchain::Blockchain,
         },
-        util::{self, serialize},
+        util::{self},
     },
     bigdecimal::FromPrimitive,
     ethcontract::BlockId,
     futures::future::join_all,
     hyper::StatusCode,
+    number::U256,
     secp256k1::SecretKey,
-    serde_with::serde_as,
     std::{
         collections::{HashMap, HashSet},
         path::PathBuf,
@@ -59,16 +59,16 @@ pub enum Partial {
     },
 }
 
-#[serde_as]
 #[derive(Debug, Clone, serde::Serialize)]
 #[serde(rename_all = "camelCase", tag = "kind")]
 pub enum Score {
     Solver {
-        #[serde_as(as = "serialize::U256")]
-        score: eth::U256,
+        score: U256,
     },
     #[serde(rename_all = "camelCase")]
-    RiskAdjusted { success_probability: f64 },
+    RiskAdjusted {
+        success_probability: f64,
+    },
 }
 
 impl Default for Score {
diff --git a/crates/driver/src/tests/setup/solver.rs b/crates/driver/src/tests/setup/solver.rs
index ec8b717c44..dbe47b29f6 100644
--- a/crates/driver/src/tests/setup/solver.rs
+++ b/crates/driver/src/tests/setup/solver.rs
@@ -204,7 +204,7 @@ impl Solver {
                 rpc.web3(),
                 &[infra::mempool::Config {
                     min_priority_fee: Default::default(),
-                    gas_price_cap: eth::U256::MAX,
+                    gas_price_cap: eth::U256::MAX.into(),
                     target_confirm_time: Default::default(),
                     max_confirm_time: Default::default(),
                     retry_interval: Default::default(),
diff --git a/crates/driver/src/util/serialize/mod.rs b/crates/driver/src/util/serialize/mod.rs
index 71ee479979..afb1458ea0 100644
--- a/crates/driver/src/util/serialize/mod.rs
+++ b/crates/driver/src/util/serialize/mod.rs
@@ -1,6 +1,6 @@
 //! Serialization utilities for use with [`serde_with::serde_as`] macros.
 
 mod hex;
-mod u256;
+// mod u256;
 
-pub use {self::hex::Hex, u256::U256};
+pub use {self::hex::Hex /* , u256::U256 */};
diff --git a/crates/number/Cargo.toml b/crates/number/Cargo.toml
index b23587ca86..942e7df405 100644
--- a/crates/number/Cargo.toml
+++ b/crates/number/Cargo.toml
@@ -8,6 +8,7 @@ license = "MIT OR Apache-2.0"
 [dependencies]
 anyhow = { workspace = true }
 bigdecimal = { workspace = true }
+derive_more = "0.99.0"
 num = { workspace = true }
 primitive-types = { workspace = true }
 serde_with = { workspace = true }
diff --git a/crates/number/src/lib.rs b/crates/number/src/lib.rs
index 5d277018a1..c8c00067c9 100644
--- a/crates/number/src/lib.rs
+++ b/crates/number/src/lib.rs
@@ -1,3 +1,5 @@
 pub mod conversions;
 pub mod nonzero;
 pub mod serialization;
+
+pub use serialization::U256;
diff --git a/crates/number/src/serialization.rs b/crates/number/src/serialization.rs
index 3f57cffa11..97462b814e 100644
--- a/crates/number/src/serialization.rs
+++ b/crates/number/src/serialization.rs
@@ -1,14 +1,21 @@
 use {
-    primitive_types::U256,
-    serde::{de, Deserializer, Serializer},
+    derive_more::{From, Into},
+    primitive_types::U256 as RawU256,
+    serde::{
+        de::{self, Visitor},
+        Deserialize,
+        Deserializer,
+        Serialize,
+        Serializer,
+    },
     serde_with::{DeserializeAs, SerializeAs},
-    std::fmt,
+    std::{cmp::Ordering, fmt},
 };
 
 pub struct HexOrDecimalU256;
 
-impl<'de> DeserializeAs<'de, U256> for HexOrDecimalU256 {
-    fn deserialize_as<D>(deserializer: D) -> Result<U256, D::Error>
+impl<'de> DeserializeAs<'de, RawU256> for HexOrDecimalU256 {
+    fn deserialize_as<D>(deserializer: D) -> Result<RawU256, D::Error>
     where
         D: Deserializer<'de>,
     {
@@ -16,8 +23,8 @@ impl<'de> DeserializeAs<'de, U256> for HexOrDecimalU256 {
     }
 }
 
-impl SerializeAs<U256> for HexOrDecimalU256 {
-    fn serialize_as<S>(source: &U256, serializer: S) -> Result<S::Ok, S::Error>
+impl SerializeAs<RawU256> for HexOrDecimalU256 {
+    fn serialize_as<S>(source: &RawU256, serializer: S) -> Result<S::Ok, S::Error>
     where
         S: Serializer,
     {
@@ -25,20 +32,20 @@ impl SerializeAs<U256> for HexOrDecimalU256 {
     }
 }
 
-pub fn serialize<S>(value: &U256, serializer: S) -> Result<S::Ok, S::Error>
+pub fn serialize<S>(value: &RawU256, serializer: S) -> Result<S::Ok, S::Error>
 where
     S: Serializer,
 {
     serializer.serialize_str(&value.to_string())
 }
 
-pub fn deserialize<'de, D>(deserializer: D) -> Result<U256, D::Error>
+pub fn deserialize<'de, D>(deserializer: D) -> Result<RawU256, D::Error>
 where
     D: Deserializer<'de>,
 {
     struct Visitor {}
     impl<'de> de::Visitor<'de> for Visitor {
-        type Value = U256;
+        type Value = RawU256;
 
         fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
             write!(
@@ -52,11 +59,11 @@ where
             E: de::Error,
         {
             if s.trim().starts_with("0x") {
-                U256::from_str_radix(s, 16).map_err(|err| {
+                RawU256::from_str_radix(s, 16).map_err(|err| {
                     de::Error::custom(format!("failed to decode {s:?} as hex u256: {err}"))
                 })
             } else {
-                U256::from_dec_str(s).map_err(|err| {
+                RawU256::from_dec_str(s).map_err(|err| {
                     de::Error::custom(format!("failed to decode {s:?} as decimal u256: {err}"))
                 })
             }
@@ -66,6 +73,112 @@ where
     deserializer.deserialize_str(Visitor {})
 }
 
+/// Serialize and deserialize [`U256`] as a decimal string.
+#[derive(Debug, Clone, Copy, Default, From, Into, Eq)]
+pub struct U256(RawU256);
+
+impl<'de> DeserializeAs<'de, RawU256> for U256 {
+    fn deserialize_as<D: Deserializer<'de>>(deserializer: D) -> Result<RawU256, D::Error> {
+        struct Visitor;
+
+        impl<'de> de::Visitor<'de> for Visitor {
+            type Value = RawU256;
+
+            fn expecting(&self, formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
+                write!(formatter, "a 256-bit decimal string")
+            }
+
+            fn visit_str<E>(self, s: &str) -> Result<Self::Value, E>
+            where
+                E: de::Error,
+            {
+                RawU256::from_dec_str(s).map_err(|err| {
+                    de::Error::custom(format!("failed to decode {s:?} as a 256-bit number: {err}"))
+                })
+            }
+        }
+
+        deserializer.deserialize_str(Visitor)
+    }
+}
+
+impl<'de> Deserialize<'de> for U256 {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        struct U256Visitor;
+
+        impl<'de> Visitor<'de> for U256Visitor {
+            type Value = U256;
+
+            fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+                write!(formatter, "a 256-bit decimal string")
+            }
+
+            fn visit_str<E>(self, s: &str) -> Result<Self::Value, E>
+            where
+                E: de::Error,
+            {
+                RawU256::from_dec_str(s).map(U256).map_err(|err| {
+                    E::custom(format!("failed to decode {s:?} as a 256-bit number: {err}"))
+                })
+            }
+        }
+
+        deserializer.deserialize_str(U256Visitor)
+    }
+}
+
+impl SerializeAs<RawU256> for U256 {
+    fn serialize_as<S: Serializer>(source: &RawU256, serializer: S) -> Result<S::Ok, S::Error> {
+        serializer.serialize_str(&source.to_string())
+    }
+}
+
+impl Serialize for U256 {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        U256::serialize_as(&self.0, serializer)
+    }
+}
+
+impl U256 {
+    pub fn saturating_sub(&self, other: Self) -> Self {
+        Self(self.0.saturating_sub(other.into()))
+    }
+
+    pub fn to_f64_lossy(&self) -> f64 {
+        self.0.to_f64_lossy()
+    }
+}
+
+impl PartialEq for U256 {
+    fn eq(&self, other: &Self) -> bool {
+        self.0 == other.0
+    }
+}
+
+impl PartialOrd for U256 {
+    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+        Some(self.cmp(other))
+    }
+}
+
+impl Ord for U256 {
+    fn cmp(&self, other: &Self) -> Ordering {
+        self.0.cmp(&other.0)
+    }
+}
+
+impl From<u128> for U256 {
+    fn from(value: u128) -> Self {
+        Self(RawU256::from(value))
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use {
diff --git a/crates/solvers/Cargo.toml b/crates/solvers/Cargo.toml
index a20d616c99..b31c43b89f 100644
--- a/crates/solvers/Cargo.toml
+++ b/crates/solvers/Cargo.toml
@@ -25,6 +25,7 @@ humantime-serde = { workspace = true }
 hyper = "0.14"
 itertools = "0.11"
 num = "0.4"
+number = { path = "../number" }
 prometheus = { workspace = true }
 prometheus-metric-storage = { workspace = true }
 rate-limit = { path = "../rate-limit" }
diff --git a/crates/solvers/src/domain/eth/mod.rs b/crates/solvers/src/domain/eth/mod.rs
index 82023089dd..9cde9b8f9b 100644
--- a/crates/solvers/src/domain/eth/mod.rs
+++ b/crates/solvers/src/domain/eth/mod.rs
@@ -1,4 +1,4 @@
-use {crate::util::bytes::Bytes, web3::types::AccessList};
+use {crate::util::bytes::Bytes, number::U256 as NumberU256, web3::types::AccessList};
 
 mod chain;
 
@@ -45,6 +45,12 @@ impl From<U256> for Ether {
     }
 }
 
+impl From<NumberU256> for Ether {
+    fn from(value: NumberU256) -> Self {
+        Self(value.into())
+    }
+}
+
 /// Gas amount.
 #[derive(Clone, Copy, Debug, Default)]
 pub struct Gas(pub U256);