diff --git a/Cargo.lock b/Cargo.lock
index 39cad7b3a..e01b8fff1 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -17,10 +17,21 @@ version = "2.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "512761e0bb2578dd7380c6baaa0f4ce03e84f95e960231d1dec8bf4d7d6e2627"
 
+[[package]]
+name = "affine_common"
+version = "0.1.0"
+dependencies = [
+ "chrono",
+ "rand",
+ "rayon",
+ "sha3",
+]
+
 [[package]]
 name = "affine_native"
 version = "0.0.0"
 dependencies = [
+ "affine_common",
  "affine_schema",
  "anyhow",
  "chrono",
@@ -49,6 +60,7 @@ version = "0.0.0"
 name = "affine_server_native"
 version = "1.0.0"
 dependencies = [
+ "affine_common",
  "chrono",
  "file-format",
  "mimalloc",
diff --git a/Cargo.toml b/Cargo.toml
index c8282b0cd..1a3af2181 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,30 +1,36 @@
 [workspace]
-members  = ["./packages/backend/native", "./packages/frontend/native", "./packages/frontend/native/schema"]
+members  = [
+    "./packages/backend/native",
+    "./packages/common/native",
+    "./packages/frontend/native",
+    "./packages/frontend/native/schema"
+]
 resolver = "2"
 
 [workspace.dependencies]
-anyhow       = "1"
-chrono       = "0.4"
-dotenv       = "0.15"
-file-format  = { version = "0.26", features = ["reader"] }
-mimalloc     = "0.1"
-napi         = { version = "3.0.0-alpha.12", features = ["async", "chrono_date", "error_anyhow", "napi9", "serde"] }
-napi-build   = { version = "2" }
-napi-derive  = { version = "3.0.0-alpha.12" }
-notify       = { version = "7", features = ["serde"] }
-once_cell    = "1"
-parking_lot  = "0.12"
-rand         = "0.8"
-rayon        = "1.10"
-serde        = "1"
-serde_json   = "1"
-sha3         = "0.10"
-sqlx         = { version = "0.8", default-features = false, features = ["chrono", "macros", "migrate", "runtime-tokio", "sqlite", "tls-rustls"] }
-tiktoken-rs  = "0.6"
-tokio        = "1.37"
-uuid         = "1.8"
-v_htmlescape = "0.15"
-y-octo       = { git = "https://github.com/y-crdt/y-octo.git", branch = "main" }
+affine_common = { path = "./packages/common/native" }
+anyhow        = "1"
+chrono        = "0.4"
+dotenv        = "0.15"
+file-format   = { version = "0.26", features = ["reader"] }
+mimalloc      = "0.1"
+napi          = { version = "3.0.0-alpha.12", features = ["async", "chrono_date", "error_anyhow", "napi9", "serde"] }
+napi-build    = { version = "2" }
+napi-derive   = { version = "3.0.0-alpha.12" }
+notify        = { version = "7", features = ["serde"] }
+once_cell     = "1"
+parking_lot   = "0.12"
+rand          = "0.8"
+rayon         = "1.10"
+serde         = "1"
+serde_json    = "1"
+sha3          = "0.10"
+sqlx          = { version = "0.8", default-features = false, features = ["chrono", "macros", "migrate", "runtime-tokio", "sqlite", "tls-rustls"] }
+tiktoken-rs   = "0.6"
+tokio         = "1.37"
+uuid          = "1.8"
+v_htmlescape  = "0.15"
+y-octo        = { git = "https://github.com/y-crdt/y-octo.git", branch = "main" }
 
 [profile.dev.package.sqlx-macros]
 opt-level = 3
diff --git a/packages/backend/native/Cargo.toml b/packages/backend/native/Cargo.toml
index 2d85b32f7..f1c55f33a 100644
--- a/packages/backend/native/Cargo.toml
+++ b/packages/backend/native/Cargo.toml
@@ -7,15 +7,16 @@ version = "1.0.0"
 crate-type = ["cdylib"]
 
 [dependencies]
-chrono       = { workspace = true }
-file-format  = { workspace = true }
-napi         = { workspace = true }
-napi-derive  = { workspace = true }
-rand         = { workspace = true }
-sha3         = { workspace = true }
-tiktoken-rs  = { workspace = true }
-v_htmlescape = { workspace = true }
-y-octo       = { workspace = true }
+affine_common = { workspace = true }
+chrono        = { workspace = true }
+file-format   = { workspace = true }
+napi          = { workspace = true }
+napi-derive   = { workspace = true }
+rand          = { workspace = true }
+sha3          = { workspace = true }
+tiktoken-rs   = { workspace = true }
+v_htmlescape  = { workspace = true }
+y-octo        = { workspace = true }
 
 [target.'cfg(not(target_os = "linux"))'.dependencies]
 mimalloc = { workspace = true }
diff --git a/packages/backend/native/src/hashcash.rs b/packages/backend/native/src/hashcash.rs
deleted file mode 120000
index 37297e192..000000000
--- a/packages/backend/native/src/hashcash.rs
+++ /dev/null
@@ -1 +0,0 @@
-../../../frontend/native/src/hashcash.rs
\ No newline at end of file
diff --git a/packages/backend/native/src/hashcash.rs b/packages/backend/native/src/hashcash.rs
new file mode 100644
index 000000000..a9aa75f0b
--- /dev/null
+++ b/packages/backend/native/src/hashcash.rs
@@ -0,0 +1,69 @@
+use std::convert::TryFrom;
+
+use affine_common::hashcash::Stamp;
+use napi::{bindgen_prelude::AsyncTask, Env, JsBoolean, JsString, Result as NapiResult, Task};
+use napi_derive::napi;
+
+pub struct AsyncVerifyChallengeResponse {
+  response: String,
+  bits: u32,
+  resource: String,
+}
+
+#[napi]
+impl Task for AsyncVerifyChallengeResponse {
+  type Output = bool;
+  type JsValue = JsBoolean;
+
+  fn compute(&mut self) -> NapiResult<Self::Output> {
+    Ok(if let Ok(stamp) = Stamp::try_from(self.response.as_str()) {
+      stamp.check(self.bits, &self.resource)
+    } else {
+      false
+    })
+  }
+
+  fn resolve(&mut self, env: Env, output: bool) -> NapiResult<Self::JsValue> {
+    env.get_boolean(output)
+  }
+}
+
+#[napi]
+pub fn verify_challenge_response(
+  response: String,
+  bits: u32,
+  resource: String,
+) -> AsyncTask<AsyncVerifyChallengeResponse> {
+  AsyncTask::new(AsyncVerifyChallengeResponse {
+    response,
+    bits,
+    resource,
+  })
+}
+
+pub struct AsyncMintChallengeResponse {
+  bits: Option<u32>,
+  resource: String,
+}
+
+#[napi]
+impl Task for AsyncMintChallengeResponse {
+  type Output = String;
+  type JsValue = JsString;
+
+  fn compute(&mut self) -> NapiResult<Self::Output> {
+    Ok(Stamp::mint(self.resource.clone(), self.bits).format())
+  }
+
+  fn resolve(&mut self, env: Env, output: String) -> NapiResult<Self::JsValue> {
+    env.create_string(&output)
+  }
+}
+
+#[napi]
+pub fn mint_challenge_response(
+  resource: String,
+  bits: Option<u32>,
+) -> AsyncTask<AsyncMintChallengeResponse> {
+  AsyncTask::new(AsyncMintChallengeResponse { bits, resource })
+}
diff --git a/packages/backend/server/migrations/migration_lock.toml b/packages/backend/server/migrations/migration_lock.toml
index fbffa92c2..99e4f2009 100644
--- a/packages/backend/server/migrations/migration_lock.toml
+++ b/packages/backend/server/migrations/migration_lock.toml
@@ -1,3 +1,3 @@
 # Please do not edit this file manually
 # It should be added in your version-control system (i.e. Git)
-provider = "postgresql"
\ No newline at end of file
+provider = "postgresql"
diff --git a/packages/common/native/Cargo.toml b/packages/common/native/Cargo.toml
new file mode 100644
index 000000000..88b585d2c
--- /dev/null
+++ b/packages/common/native/Cargo.toml
@@ -0,0 +1,12 @@
+[package]
+edition = "2021"
+name    = "affine_common"
+version = "0.1.0"
+
+[dependencies]
+chrono = { workspace = true }
+rand   = { workspace = true }
+sha3   = { workspace = true }
+
+[dev-dependencies]
+rayon = { workspace = true }
diff --git a/packages/common/native/src/hashcash.rs b/packages/common/native/src/hashcash.rs
new file mode 100644
index 000000000..d5cee2890
--- /dev/null
+++ b/packages/common/native/src/hashcash.rs
@@ -0,0 +1,204 @@
+use std::convert::TryFrom;
+
+use chrono::{DateTime, Duration, NaiveDateTime, Utc};
+use rand::{
+  distributions::{Alphanumeric, Distribution},
+  thread_rng,
+};
+use sha3::{Digest, Sha3_256};
+
+const SALT_LENGTH: usize = 16;
+
+#[derive(Debug)]
+pub struct Stamp {
+  version: String,
+  claim: u32,
+  ts: String,
+  resource: String,
+  ext: String,
+  rand: String,
+  counter: String,
+}
+
+impl Stamp {
+  fn check_expiration(&self) -> bool {
+    NaiveDateTime::parse_from_str(&self.ts, "%Y%m%d%H%M%S")
+      .ok()
+      .map(|ts| DateTime::<Utc>::from_naive_utc_and_offset(ts, Utc))
+      .and_then(|utc| {
+        utc
+          .checked_add_signed(Duration::minutes(5))
+          .map(|utc| Utc::now() <= utc)
+      })
+      .unwrap_or(false)
+  }
+
+  pub fn check<S: AsRef<str>>(&self, bits: u32, resource: S) -> bool {
+    if self.version == "1"
+      && bits <= self.claim
+      && self.check_expiration()
+      && self.resource == resource.as_ref()
+    {
+      let hex_digits = ((self.claim as f32) / 4.).floor() as usize;
+
+      // check challenge
+      let mut hasher = Sha3_256::new();
+      hasher.update(self.format().as_bytes());
+      let result = format!("{:x}", hasher.finalize());
+      result[..hex_digits] == String::from_utf8(vec![b'0'; hex_digits]).unwrap()
+    } else {
+      false
+    }
+  }
+
+  pub fn format(&self) -> String {
+    format!(
+      "{}:{}:{}:{}:{}:{}:{}",
+      self.version, self.claim, self.ts, self.resource, self.ext, self.rand, self.counter
+    )
+  }
+
+  /// Mint a new hashcash stamp.
+  pub fn mint(resource: String, bits: Option<u32>) -> Self {
+    let version = "1";
+    let now = Utc::now();
+    let ts = now.format("%Y%m%d%H%M%S");
+    let bits = bits.unwrap_or(20);
+    let rand = String::from_iter(
+      Alphanumeric
+        .sample_iter(thread_rng())
+        .take(SALT_LENGTH)
+        .map(char::from),
+    );
+    let challenge = format!("{}:{}:{}:{}:{}:{}", version, bits, ts, &resource, "", rand);
+
+    Stamp {
+      version: version.to_string(),
+      claim: bits,
+      ts: ts.to_string(),
+      resource,
+      ext: "".to_string(),
+      rand,
+      counter: {
+        let mut hasher = Sha3_256::new();
+        let mut counter = 0;
+        let hex_digits = ((bits as f32) / 4.).ceil() as usize;
+        let zeros = String::from_utf8(vec![b'0'; hex_digits]).unwrap();
+        loop {
+          hasher.update(format!("{}:{:x}", challenge, counter).as_bytes());
+          let result = format!("{:x}", hasher.finalize_reset());
+          if result[..hex_digits] == zeros {
+            break format!("{:x}", counter);
+          };
+          counter += 1
+        }
+      },
+    }
+  }
+}
+
+impl TryFrom<&str> for Stamp {
+  type Error = String;
+
+  fn try_from(value: &str) -> Result<Self, Self::Error> {
+    let stamp_vec = value.split(':').collect::<Vec<&str>>();
+    if stamp_vec.len() != 7
+      || stamp_vec
+        .iter()
+        .enumerate()
+        .any(|(i, s)| i != 4 && s.is_empty())
+    {
+      return Err(format!(
+        "Malformed stamp, expected 6 parts, got {}",
+        stamp_vec.len()
+      ));
+    }
+    Ok(Stamp {
+      version: stamp_vec[0].to_string(),
+      claim: stamp_vec[1]
+        .parse()
+        .map_err(|_| "Malformed stamp".to_string())?,
+      ts: stamp_vec[2].to_string(),
+      resource: stamp_vec[3].to_string(),
+      ext: stamp_vec[4].to_string(),
+      rand: stamp_vec[5].to_string(),
+      counter: stamp_vec[6].to_string(),
+    })
+  }
+}
+
+#[cfg(test)]
+mod tests {
+  use super::Stamp;
+  use rand::{distributions::Alphanumeric, Rng};
+  use rayon::prelude::*;
+
+  #[test]
+  fn test_mint() {
+    {
+      let response = Stamp::mint("test".into(), Some(20)).format();
+      assert!(
+        Stamp::try_from(response.as_str())
+          .unwrap()
+          .check(20, "test"),
+        "should pass"
+      );
+    }
+
+    {
+      let response = Stamp::mint("test".into(), Some(19)).format();
+      assert!(
+        !Stamp::try_from(response.as_str())
+          .unwrap()
+          .check(20, "test"),
+        "should fail with lower bits"
+      );
+    }
+    {
+      let response = Stamp::mint("test".into(), Some(20)).format();
+      assert!(
+        !Stamp::try_from(response.as_str())
+          .unwrap()
+          .check(20, "test2"),
+        "should fail with different resource"
+      );
+    }
+  }
+
+  #[test]
+  fn test_check_expiration() {
+    let response = Stamp::mint("test".into(), Some(20));
+    assert!(response.check_expiration());
+  }
+
+  #[test]
+  fn test_format() {
+    let response = Stamp::mint("test".into(), Some(20));
+    assert_eq!(
+      response.format(),
+      format!(
+        "1:20:{}:test::{}:{}",
+        response.ts, response.rand, response.counter
+      )
+    );
+  }
+
+  #[test]
+  fn test_fuzz() {
+    (0..1000).into_par_iter().for_each(|_| {
+      let bit = rand::random::<u32>() % 20 + 1;
+      let resource = rand::thread_rng()
+        .sample_iter(&Alphanumeric)
+        .take(7)
+        .map(char::from)
+        .collect::<String>();
+      let response = Stamp::mint(resource.clone(), Some(bit)).format();
+      assert!(
+        Stamp::try_from(response.as_str())
+          .unwrap()
+          .check(bit, resource),
+        "should pass"
+      );
+    });
+  }
+}
diff --git a/packages/common/native/src/lib.rs b/packages/common/native/src/lib.rs
new file mode 100644
index 000000000..908ae1a77
--- /dev/null
+++ b/packages/common/native/src/lib.rs
@@ -0,0 +1 @@
+pub mod hashcash;
diff --git a/packages/frontend/native/Cargo.toml b/packages/frontend/native/Cargo.toml
index aa29af594..0fc3c7e3f 100644
--- a/packages/frontend/native/Cargo.toml
+++ b/packages/frontend/native/Cargo.toml
@@ -7,6 +7,7 @@ version = "0.0.0"
 crate-type = ["cdylib"]
 
 [dependencies]
+affine_common = { workspace = true }
 affine_schema = { path = "./schema" }
 anyhow        = { workspace = true }
 chrono        = { workspace = true }
@@ -24,7 +25,7 @@ tokio         = { workspace = true, features = ["full"] }
 uuid          = { workspace = true, features = ["fast-rng", "serde", "v4"] }
 
 [dev-dependencies]
-rayon         = { workspace = true }
+rayon = { workspace = true }
 
 [build-dependencies]
 affine_schema = { path = "./schema" }
diff --git a/packages/frontend/native/src/hashcash.rs b/packages/frontend/native/src/hashcash.rs
index 30120b3c8..a9aa75f0b 100644
--- a/packages/frontend/native/src/hashcash.rs
+++ b/packages/frontend/native/src/hashcash.rs
@@ -1,133 +1,8 @@
 use std::convert::TryFrom;
 
-use chrono::{DateTime, Duration, NaiveDateTime, Utc};
+use affine_common::hashcash::Stamp;
 use napi::{bindgen_prelude::AsyncTask, Env, JsBoolean, JsString, Result as NapiResult, Task};
 use napi_derive::napi;
-use rand::{
-  distributions::{Alphanumeric, Distribution},
-  thread_rng,
-};
-use sha3::{Digest, Sha3_256};
-
-const SALT_LENGTH: usize = 16;
-
-#[derive(Debug)]
-struct Stamp {
-  version: String,
-  claim: u32,
-  ts: String,
-  resource: String,
-  ext: String,
-  rand: String,
-  counter: String,
-}
-
-impl Stamp {
-  fn check_expiration(&self) -> bool {
-    NaiveDateTime::parse_from_str(&self.ts, "%Y%m%d%H%M%S")
-      .ok()
-      .map(|ts| DateTime::<Utc>::from_naive_utc_and_offset(ts, Utc))
-      .and_then(|utc| {
-        utc
-          .checked_add_signed(Duration::minutes(5))
-          .map(|utc| Utc::now() <= utc)
-      })
-      .unwrap_or(false)
-  }
-
-  pub fn check<S: AsRef<str>>(&self, bits: u32, resource: S) -> bool {
-    if self.version == "1"
-      && bits <= self.claim
-      && self.check_expiration()
-      && self.resource == resource.as_ref()
-    {
-      let hex_digits = ((self.claim as f32) / 4.).floor() as usize;
-
-      // check challenge
-      let mut hasher = Sha3_256::new();
-      hasher.update(self.format().as_bytes());
-      let result = format!("{:x}", hasher.finalize());
-      result[..hex_digits] == String::from_utf8(vec![b'0'; hex_digits]).unwrap()
-    } else {
-      false
-    }
-  }
-
-  fn format(&self) -> String {
-    format!(
-      "{}:{}:{}:{}:{}:{}:{}",
-      self.version, self.claim, self.ts, self.resource, self.ext, self.rand, self.counter
-    )
-  }
-
-  /// Mint a new hashcash stamp.
-  pub fn mint(resource: String, bits: Option<u32>) -> Self {
-    let version = "1";
-    let now = Utc::now();
-    let ts = now.format("%Y%m%d%H%M%S");
-    let bits = bits.unwrap_or(20);
-    let rand = String::from_iter(
-      Alphanumeric
-        .sample_iter(thread_rng())
-        .take(SALT_LENGTH)
-        .map(char::from),
-    );
-    let challenge = format!("{}:{}:{}:{}:{}:{}", version, bits, ts, &resource, "", rand);
-
-    Stamp {
-      version: version.to_string(),
-      claim: bits,
-      ts: ts.to_string(),
-      resource,
-      ext: "".to_string(),
-      rand,
-      counter: {
-        let mut hasher = Sha3_256::new();
-        let mut counter = 0;
-        let hex_digits = ((bits as f32) / 4.).ceil() as usize;
-        let zeros = String::from_utf8(vec![b'0'; hex_digits]).unwrap();
-        loop {
-          hasher.update(format!("{}:{:x}", challenge, counter).as_bytes());
-          let result = format!("{:x}", hasher.finalize_reset());
-          if result[..hex_digits] == zeros {
-            break format!("{:x}", counter);
-          };
-          counter += 1
-        }
-      },
-    }
-  }
-}
-
-impl TryFrom<&str> for Stamp {
-  type Error = String;
-
-  fn try_from(value: &str) -> Result<Self, Self::Error> {
-    let stamp_vec = value.split(':').collect::<Vec<&str>>();
-    if stamp_vec.len() != 7
-      || stamp_vec
-        .iter()
-        .enumerate()
-        .any(|(i, s)| i != 4 && s.is_empty())
-    {
-      return Err(format!(
-        "Malformed stamp, expected 6 parts, got {}",
-        stamp_vec.len()
-      ));
-    }
-    Ok(Stamp {
-      version: stamp_vec[0].to_string(),
-      claim: stamp_vec[1]
-        .parse()
-        .map_err(|_| "Malformed stamp".to_string())?,
-      ts: stamp_vec[2].to_string(),
-      resource: stamp_vec[3].to_string(),
-      ext: stamp_vec[4].to_string(),
-      rand: stamp_vec[5].to_string(),
-      counter: stamp_vec[6].to_string(),
-    })
-  }
-}
 
 pub struct AsyncVerifyChallengeResponse {
   response: String,
@@ -192,79 +67,3 @@ pub fn mint_challenge_response(
 ) -> AsyncTask<AsyncMintChallengeResponse> {
   AsyncTask::new(AsyncMintChallengeResponse { bits, resource })
 }
-
-#[cfg(test)]
-mod tests {
-  use super::Stamp;
-  use rand::{distributions::Alphanumeric, Rng};
-  use rayon::prelude::*;
-
-  #[test]
-  fn test_mint() {
-    {
-      let response = Stamp::mint("test".into(), Some(20)).format();
-      assert!(
-        Stamp::try_from(response.as_str())
-          .unwrap()
-          .check(20, "test"),
-        "should pass"
-      );
-    }
-
-    {
-      let response = Stamp::mint("test".into(), Some(19)).format();
-      assert!(
-        !Stamp::try_from(response.as_str())
-          .unwrap()
-          .check(20, "test"),
-        "should fail with lower bits"
-      );
-    }
-    {
-      let response = Stamp::mint("test".into(), Some(20)).format();
-      assert!(
-        !Stamp::try_from(response.as_str())
-          .unwrap()
-          .check(20, "test2"),
-        "should fail with different resource"
-      );
-    }
-  }
-
-  #[test]
-  fn test_check_expiration() {
-    let response = Stamp::mint("test".into(), Some(20));
-    assert!(response.check_expiration());
-  }
-
-  #[test]
-  fn test_format() {
-    let response = Stamp::mint("test".into(), Some(20));
-    assert_eq!(
-      response.format(),
-      format!(
-        "1:20:{}:test::{}:{}",
-        response.ts, response.rand, response.counter
-      )
-    );
-  }
-
-  #[test]
-  fn test_fuzz() {
-    (0..1000).into_par_iter().for_each(|_| {
-      let bit = rand::random::<u32>() % 20 + 1;
-      let resource = rand::thread_rng()
-        .sample_iter(&Alphanumeric)
-        .take(7)
-        .map(char::from)
-        .collect::<String>();
-      let response = Stamp::mint(resource.clone(), Some(bit)).format();
-      assert!(
-        Stamp::try_from(response.as_str())
-          .unwrap()
-          .check(bit, resource),
-        "should pass"
-      );
-    });
-  }
-}