diff --git a/.gitignore b/.gitignore
index ea8c4bf..71c4f75 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,4 @@
 /target
+*.db
+*.db3
+*.env
diff --git a/Cargo.toml b/Cargo.toml
index 80a0b3a..786f1a9 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -12,7 +12,7 @@ dotenvy = "0.15.7"
 maud = { version = "0.27.0", features = ["axum"] }
 rand = "0.10.0"
 rusqlite = { version = "0.38.0", features = ["bundled", "chrono", "uuid"] }
-serde = "1.0.228"
+serde = { version = "1.0.228", features = ["derive"] }
 serde_json = "1.0.149"
 thiserror = "2.0.18"
 tokio = { version = "1.49.0", features = ["full"] }
diff --git a/src/main.rs b/src/main.rs
index 189b68b..30908b2 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,5 +1,13 @@
-mod database;
+use std::error::Error;
 
-fn main() {
+mod database;
+mod persons;
+mod quotes;
+mod tags;
+mod users;
+
+fn main() -> Result<(), Box<dyn Error>> {
     println!("Hello, world!");
+
+    Ok(())
 }
diff --git a/src/persons/mod.rs b/src/persons/mod.rs
new file mode 100644
index 0000000..b6fd5d9
--- /dev/null
+++ b/src/persons/mod.rs
@@ -0,0 +1,3 @@
+pub mod names;
+
+pub struct Person;
diff --git a/src/persons/names.rs b/src/persons/names.rs
new file mode 100644
index 0000000..a050f41
--- /dev/null
+++ b/src/persons/names.rs
@@ -0,0 +1 @@
+pub struct Name;
diff --git a/src/quotes/lines.rs b/src/quotes/lines.rs
new file mode 100644
index 0000000..64cd091
--- /dev/null
+++ b/src/quotes/lines.rs
@@ -0,0 +1 @@
+pub struct QuoteLine;
diff --git a/src/quotes/mod.rs b/src/quotes/mod.rs
new file mode 100644
index 0000000..b22580d
--- /dev/null
+++ b/src/quotes/mod.rs
@@ -0,0 +1,3 @@
+pub mod lines;
+
+pub struct Quote;
diff --git a/src/tags.rs b/src/tags.rs
new file mode 100644
index 0000000..7fe1c9e
--- /dev/null
+++ b/src/tags.rs
@@ -0,0 +1 @@
+pub struct Tag;
diff --git a/src/users/auth.rs b/src/users/auth.rs
new file mode 100644
index 0000000..e69de29
diff --git a/src/users/handle.rs b/src/users/handle.rs
new file mode 100644
index 0000000..af11473
--- /dev/null
+++ b/src/users/handle.rs
@@ -0,0 +1,91 @@
+use std::{fmt::Display, ops::Deref, str::FromStr};
+
+use rusqlite::{
+    Result as RusqliteResult,
+    types::{FromSql, FromSqlError, FromSqlResult, ToSql, ToSqlOutput, ValueRef},
+};
+use serde::{Deserialize, Serialize};
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash, Serialize, Deserialize, PartialOrd, Ord)]
+#[serde(into = "String")]
+#[serde(try_from = "String")]
+pub struct UserHandle(String);
+
+#[derive(Debug, thiserror::Error, Clone, PartialEq)]
+pub enum UserHandleError {
+    #[error("Handle is too short - must be 3 or more characters.")]
+    HandleTooShort,
+    #[error("Handle is too long - must be 16 or less characters.")]
+    HandleTooLong,
+    #[error("Handle must consist of ASCII alphanumeric characters only.")]
+    HandleNonAsciiAlphanumeric,
+}
+
+impl UserHandle {
+    pub fn new(input: impl AsRef<str>) -> Result<Self, UserHandleError> {
+        let s = input.as_ref();
+        UserHandle::validate_str(s)?;
+        Ok(UserHandle(s.to_string()))
+    }
+    pub fn validate_str(str: &str) -> Result<(), UserHandleError> {
+        match str.len() {
+            ..=2 => return Err(UserHandleError::HandleTooShort),
+            17.. => return Err(UserHandleError::HandleTooLong),
+            _ => (),
+        };
+        if str.bytes().any(|c| !c.is_ascii_alphanumeric()) {
+            return Err(UserHandleError::HandleNonAsciiAlphanumeric);
+        }
+        Ok(())
+    }
+    pub fn as_str(&self) -> &str {
+        &self.0
+    }
+}
+impl AsRef<str> for UserHandle {
+    fn as_ref(&self) -> &str {
+        &self.0
+    }
+}
+impl Deref for UserHandle {
+    type Target = str;
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+impl Display for UserHandle {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", self.0)
+    }
+}
+impl FromStr for UserHandle {
+    type Err = UserHandleError;
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        Self::validate_str(s)?;
+        Ok(UserHandle(s.to_string()))
+    }
+}
+impl TryFrom<String> for UserHandle {
+    type Error = UserHandleError;
+    fn try_from(value: String) -> Result<Self, Self::Error> {
+        Self::validate_str(&value)?;
+        Ok(UserHandle(value))
+    }
+}
+impl From<UserHandle> for String {
+    fn from(value: UserHandle) -> Self {
+        value.0
+    }
+}
+
+impl ToSql for UserHandle {
+    fn to_sql(&self) -> RusqliteResult<ToSqlOutput<'_>> {
+        Ok(self.0.to_sql()?)
+    }
+}
+
+impl FromSql for UserHandle {
+    fn column_result(value: ValueRef<'_>) -> FromSqlResult<Self> {
+        UserHandle::from_str(value.as_str()?).map_err(|e| FromSqlError::Other(Box::new(e)))
+    }
+}
diff --git a/src/users/mod.rs b/src/users/mod.rs
new file mode 100644
index 0000000..41df237
--- /dev/null
+++ b/src/users/mod.rs
@@ -0,0 +1,14 @@
+use serde::{Deserialize, Serialize};
+use uuid::Uuid;
+
+use crate::users::handle::UserHandle;
+
+pub mod auth;
+pub mod handle;
+pub mod sessions;
+
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
+pub struct User {
+    pub id: Uuid,
+    pub handle: UserHandle,
+}
diff --git a/src/users/sessions.rs b/src/users/sessions.rs
new file mode 100644
index 0000000..e19ab6e
--- /dev/null
+++ b/src/users/sessions.rs
@@ -0,0 +1 @@
+pub struct Session;