diff --git a/rust/src/identifier.rs b/rust/src/identifier.rs
new file mode 100644
index 0000000000..b199c5838e
--- /dev/null
+++ b/rust/src/identifier.rs
@@ -0,0 +1,86 @@
+/*
+ * This file is licensed under the Affero General Public License (AGPL) version 3.
+ *
+ * Copyright (C) 2024 New Vector, Ltd
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * See the GNU Affero General Public License for more details:
+ * <https://www.gnu.org/licenses/agpl-3.0.html>.
+ */
+
+//! # Matrix Identifiers
+//!
+//! This module contains definitions and utilities for working with matrix identifiers.
+
+use std::{fmt, ops::Deref};
+
+/// Errors that can occur when parsing a matrix identifier.
+#[derive(Clone, Debug, PartialEq)]
+pub enum IdentifierError {
+ IncorrectSigil,
+ MissingColon,
+}
+
+impl fmt::Display for IdentifierError {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ write!(f, "{:?}", self)
+ }
+}
+
+/// A Matrix user_id.
+#[derive(Clone, Debug, PartialEq)]
+pub struct UserID(String);
+
+impl UserID {
+ /// Returns the `localpart` of the user_id.
+ pub fn localpart(&self) -> &str {
+ &self[1..self.colon_pos()]
+ }
+
+ /// Returns the `server_name` / `domain` of the user_id.
+ pub fn server_name(&self) -> &str {
+ &self[self.colon_pos() + 1..]
+ }
+
+ /// Returns the position of the ':' inside of the user_id.
+ /// Used when splitting the user_id into it's respective parts.
+ fn colon_pos(&self) -> usize {
+ self.find(':').unwrap()
+ }
+}
+
+impl TryFrom<&str> for UserID {
+ type Error = IdentifierError;
+
+ /// Will try creating a `UserID` from the provided `&str`.
+ /// Can fail if the user_id is incorrectly formatted.
+ fn try_from(s: &str) -> Result<Self, Self::Error> {
+ if !s.starts_with('@') {
+ return Err(IdentifierError::IncorrectSigil);
+ }
+
+ if s.find(':').is_none() {
+ return Err(IdentifierError::MissingColon);
+ }
+
+ Ok(UserID(s.to_string()))
+ }
+}
+
+impl Deref for UserID {
+ type Target = str;
+
+ fn deref(&self) -> &Self::Target {
+ &self.0
+ }
+}
+
+impl fmt::Display for UserID {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ write!(f, "{}", self.0)
+ }
+}
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