diff --git a/crates/matrix/Cargo.toml b/crates/matrix/Cargo.toml
index 68b8b70..8d24aca 100644
--- a/crates/matrix/Cargo.toml
+++ b/crates/matrix/Cargo.toml
@@ -6,18 +6,22 @@ publish = false
 
 [dependencies]
 ruma-events = { version = "0.27.11", features = ["html", "markdown"] }
-ruma-common = { version = "0.12.0", default_features = false, features = ["api", "rand"] }
+ruma-common = { version = "0.12.0", default_features = false, features = [
+  "api",
+  "rand",
+] }
 ruma-macros = "0.12.0"
 
 # Workspace Dependencies
-anyhow = { workspace = true }
-chrono = { workspace = true, features = ["serde"] }
 mime = { workspace = true }
 reqwest = { workspace = true, features = ["json"] }
 serde = { workspace = true }
 tokio = { workspace = true }
 tracing = { workspace = true }
+sha1 = { workspace = true }
 url = { workspace = true, features = ["serde"] }
+hex = { workspace = true }
+hmac = { workspace = true }
 
 [features]
 client = []
diff --git a/crates/matrix/src/admin/mod.rs b/crates/matrix/src/admin/mod.rs
index 2a77d65..dcb275b 100644
--- a/crates/matrix/src/admin/mod.rs
+++ b/crates/matrix/src/admin/mod.rs
@@ -1,3 +1,7 @@
-mod user;
+//! This module is the root of the admin API.
+//!
+//! reference: https://matrix-org.github.io/synapse/latest/usage/administration/admin_api/index.html
+
 mod room;
-// mod room;
+mod session;
+mod user;
diff --git a/crates/matrix/src/admin/room.rs b/crates/matrix/src/admin/room.rs
index 17117b9..39b3a22 100644
--- a/crates/matrix/src/admin/room.rs
+++ b/crates/matrix/src/admin/room.rs
@@ -1,6 +1,6 @@
-//! reference: https://matrix-org.github.io/synapse/latest/admin_api/rooms.html
-//!
 //! This module contains handlers for managing rooms.
+//!
+//! reference: https://matrix-org.github.io/synapse/latest/admin_api/rooms.html
 
 use ruma_common::{
     room::RoomType, EventEncryptionAlgorithm, OwnedMxcUri, OwnedRoomAliasId, OwnedRoomId,
diff --git a/crates/matrix/src/admin/session.rs b/crates/matrix/src/admin/session.rs
new file mode 100644
index 0000000..88cabf2
--- /dev/null
+++ b/crates/matrix/src/admin/session.rs
@@ -0,0 +1,45 @@
+//! This module contains handlers for user registration.
+//!
+//! reference: https://matrix-org.github.io/synapse/latest/admin_api/register_api.html
+
+use hmac::Mac;
+
+mod get_nonce;
+mod register;
+
+#[derive(Clone, Debug)]
+pub struct Hmac {
+    inner: Vec<u8>,
+}
+
+impl Hmac {
+    fn new(
+        shared_secret: &str,
+        nonce: &str,
+        username: &str,
+        password: &str,
+        admin: bool,
+    ) -> Result<Self, hmac::digest::InvalidLength> {
+        let mut mac = hmac::Hmac::<sha1::Sha1>::new_from_slice(shared_secret.as_bytes())?;
+        let admin = match admin {
+            true => "admin",
+            false => "notadmin",
+        };
+
+        mac.update(
+            &[nonce, username, password, admin]
+                .map(str::as_bytes)
+                .join(&0x00),
+        );
+
+        let result = mac.finalize().into_bytes();
+
+        Ok(Self {
+            inner: result.to_vec(),
+        })
+    }
+
+    fn get(&self) -> String {
+        hex::encode(&self.inner)
+    }
+}
diff --git a/crates/matrix/src/admin/session/get_nonce.rs b/crates/matrix/src/admin/session/get_nonce.rs
new file mode 100644
index 0000000..d5f5c00
--- /dev/null
+++ b/crates/matrix/src/admin/session/get_nonce.rs
@@ -0,0 +1,22 @@
+use ruma_common::{
+    api::{request, response, Metadata},
+    metadata,
+};
+
+#[allow(dead_code)]
+const METADATA: Metadata = metadata! {
+    method: GET,
+    rate_limited: false,
+    authentication: AccessToken,
+    history: {
+        unstable => "/_synapse/admin/v1/register",
+    }
+};
+
+#[request(error = crate::Error)]
+pub struct Request {}
+
+#[response(error = crate::Error)]
+pub struct Response {
+    nonce: String,
+}
diff --git a/crates/matrix/src/admin/session/register.rs b/crates/matrix/src/admin/session/register.rs
new file mode 100644
index 0000000..c71d8f0
--- /dev/null
+++ b/crates/matrix/src/admin/session/register.rs
@@ -0,0 +1,43 @@
+use ruma_common::{
+    api::{request, response, Metadata},
+    metadata, OwnedDeviceId, OwnedServerName, OwnedUserId,
+};
+
+use super::Hmac;
+
+#[allow(dead_code)]
+const METADATA: Metadata = metadata! {
+    method: GET,
+    rate_limited: false,
+    authentication: AccessToken,
+    history: {
+        unstable => "/_synapse/admin/v1/register",
+    }
+};
+
+#[request(error = crate::Error)]
+pub struct Request {
+    pub nonce: String,
+
+    pub username: String,
+
+    pub password: String,
+
+    #[serde(skip_deserializing_if = "String::is_empty")]
+    pub displayname: String,
+
+    pub admin: bool,
+
+    pub hmac: Hmac,
+}
+
+#[response(error = crate::Error)]
+pub struct Response {
+    pub access_token: String,
+
+    pub user_id: OwnedUserId,
+
+    pub home_server: OwnedServerName,
+
+    pub device_id: OwnedDeviceId,
+}
diff --git a/crates/matrix/src/admin/user.rs b/crates/matrix/src/admin/user.rs
index 2e39665..3417bb5 100644
--- a/crates/matrix/src/admin/user.rs
+++ b/crates/matrix/src/admin/user.rs
@@ -1,6 +1,6 @@
-//! reference: https://matrix-org.github.io/synapse/latest/admin_api/user_admin_api.html
+//! This module contains handlers for managing users.
 //!
-//! This module contains handlers for managing user accounts.
+//! reference: https://matrix-org.github.io/synapse/latest/admin_api/user_admin_api.html
 
 use ruma_common::{thirdparty::ThirdPartyIdentifier, OwnedMxcUri, OwnedUserId};
 use serde::{Deserialize, Serialize};
diff --git a/crates/matrix/src/client/error.rs b/crates/matrix/src/client/error.rs
deleted file mode 100644
index 872754b..0000000
--- a/crates/matrix/src/client/error.rs
+++ /dev/null
@@ -1,9 +0,0 @@
-use serde::Deserialize;
-
-#[derive(Clone, Debug, Deserialize)]
-pub struct MatrixError {
-    #[serde(rename = "errcode")]
-    pub error_code: String,
-    #[serde(rename = "error")]
-    pub error: String,
-}
diff --git a/crates/matrix/src/client/events.rs b/crates/matrix/src/client/events.rs
deleted file mode 100644
index 2953b2b..0000000
--- a/crates/matrix/src/client/events.rs
+++ /dev/null
@@ -1,310 +0,0 @@
-use anyhow::Result;
-use ruma_common::{serde::Raw, EventId, OwnedEventId, OwnedTransactionId, RoomId};
-
-use ruma_events::{
-    relation::RelationType, AnyMessageLikeEvent, AnyStateEvent, AnyStateEventContent,
-    AnyTimelineEvent, MessageLikeEventContent, MessageLikeEventType, StateEventContent,
-    StateEventType,
-};
-use serde::{de::DeserializeOwned, Deserialize, Serialize};
-use tracing::instrument;
-
-use crate::{admin::resources::room::Direction, error::MatrixError, Client};
-
-pub struct EventsService;
-
-#[derive(Debug, Default, Clone, Serialize)]
-pub struct GetMessagesQuery {
-    #[serde(skip_serializing_if = "Option::is_none")]
-    pub from: Option<String>,
-
-    #[serde(skip_serializing_if = "Option::is_none")]
-    pub to: Option<String>,
-
-    #[serde(skip_serializing_if = "Option::is_none")]
-    pub limit: Option<u64>,
-
-    pub dir: Direction,
-
-    #[serde(skip_serializing_if = "String::is_empty")]
-    pub filter: String,
-}
-
-#[derive(Debug, Default, Clone, Serialize)]
-pub struct GetRelationsQuery {
-    #[serde(skip_serializing_if = "Option::is_none")]
-    pub from: Option<String>,
-
-    #[serde(skip_serializing_if = "Option::is_none")]
-    pub to: Option<String>,
-
-    #[serde(skip_serializing_if = "Option::is_none")]
-    pub limit: Option<u64>,
-
-    pub dir: Direction,
-}
-
-#[derive(Debug, Deserialize)]
-pub struct GetMessagesResponse {
-    pub chunk: Vec<Raw<AnyMessageLikeEvent>>,
-    pub start: String,
-    pub end: String,
-    pub state: Option<Vec<Raw<AnyStateEvent>>>,
-}
-
-#[derive(Debug, Deserialize)]
-#[serde(transparent)]
-pub struct GetStateResponse(pub Vec<Raw<AnyStateEvent>>);
-
-#[derive(Debug, Deserialize)]
-pub struct GetRelationsResponse {
-    pub chunk: Vec<Raw<AnyTimelineEvent>>,
-    pub prev_batch: Option<String>,
-    pub next_batch: Option<String>,
-}
-
-#[derive(Debug, Default, Serialize)]
-pub struct SendRedactionBody {
-    #[serde(skip_serializing_if = "String::is_empty")]
-    pub reason: String,
-}
-
-#[derive(Debug, Deserialize)]
-pub struct SendMessageResponse {
-    pub event_id: OwnedEventId,
-}
-
-#[derive(Debug, Deserialize)]
-pub struct SendStateResponse {
-    pub event_id: OwnedEventId,
-}
-
-#[derive(Debug, Deserialize)]
-pub struct SendRedactionResponse {
-    pub event_id: OwnedEventId,
-}
-
-impl EventsService {
-    #[instrument(skip(client, access_token))]
-    pub async fn get_event(
-        client: &Client,
-        access_token: impl Into<String>,
-        room_id: &RoomId,
-        event_id: &EventId,
-    ) -> Result<Raw<AnyTimelineEvent>> {
-        let mut tmp = (*client).clone();
-        tmp.set_token(access_token)?;
-
-        let resp = tmp
-            .get(format!(
-                "/_matrix/client/v3/rooms/{room_id}/event/{event_id}",
-                room_id = room_id,
-                event_id = event_id,
-            ))
-            .await?;
-
-        Ok(resp.json().await?)
-    }
-
-    #[instrument(skip(client, access_token))]
-    pub async fn get_messages(
-        client: &Client,
-        access_token: impl Into<String>,
-        room_id: &RoomId,
-        query: GetMessagesQuery,
-    ) -> Result<GetMessagesResponse> {
-        let mut tmp = (*client).clone();
-        tmp.set_token(access_token)?;
-
-        let resp = tmp
-            .get_query(
-                format!(
-                    "/_matrix/client/v3/rooms/{room_id}/messages",
-                    room_id = room_id,
-                ),
-                &query,
-            )
-            .await?;
-
-        Ok(resp.json().await?)
-    }
-
-    #[instrument(skip(client, access_token))]
-    pub async fn get_state(
-        client: &Client,
-        access_token: impl Into<String>,
-        room_id: &RoomId,
-    ) -> Result<GetStateResponse> {
-        let mut tmp = (*client).clone();
-        tmp.set_token(access_token)?;
-
-        let resp = tmp
-            .get(format!(
-                "/_matrix/client/v3/rooms/{room_id}/state",
-                room_id = room_id,
-            ))
-            .await?;
-
-        Ok(resp.json().await?)
-    }
-
-    #[instrument(skip(client, access_token))]
-    pub async fn get_state_content(
-        client: &Client,
-        access_token: impl Into<String>,
-        room_id: &RoomId,
-        event_type: StateEventType,
-        state_key: Option<String>,
-    ) -> Result<Raw<AnyStateEventContent>> {
-        let mut tmp = (*client).clone();
-        tmp.set_token(access_token)?;
-
-        let mut path = format!(
-            "/_matrix/client/v3/rooms/{room_id}/state/{event_type}",
-            room_id = room_id,
-            event_type = event_type,
-        );
-
-        if let Some(state_key) = state_key {
-            path.push_str(&format!("/{state_key}", state_key = state_key))
-        }
-
-        let resp = tmp.get(path).await?;
-
-        Ok(resp.json().await?)
-    }
-
-    #[instrument(skip(client, access_token))]
-    pub async fn get_relations<M: DeserializeOwned>(
-        client: &Client,
-        access_token: impl Into<String>,
-        room_id: &RoomId,
-        event_id: &EventId,
-        rel_type: Option<Option<RelationType>>,
-        event_type: Option<MessageLikeEventType>,
-        query: GetRelationsQuery,
-    ) -> Result<GetRelationsResponse> {
-        let mut tmp = (*client).clone();
-        tmp.set_token(access_token)?;
-
-        let mut path = format!(
-            "/_matrix/client/v3/rooms/{room_id}/relations/{event_id}",
-            room_id = room_id,
-            event_id = event_id,
-        );
-
-        if let Some(rel_type) = rel_type {
-            path.push_str(&format!(
-                "/{rel_type}",
-                rel_type = rel_type
-                    .as_ref()
-                    .map_or("m.in_reply_to".into(), ToString::to_string)
-            ));
-
-            if let Some(event_type) = event_type {
-                path.push_str(&format!("/{event_type}", event_type = event_type))
-            }
-        }
-
-        let resp = tmp.get_query(path, &query).await?;
-
-        Ok(resp.json().await?)
-    }
-
-    #[instrument(skip(client, access_token, body))]
-    pub async fn send_message<T: MessageLikeEventContent>(
-        client: &Client,
-        access_token: impl Into<String>,
-        room_id: &RoomId,
-        txn_id: OwnedTransactionId,
-        body: T,
-    ) -> Result<SendMessageResponse> {
-        let mut tmp = (*client).clone();
-        tmp.set_token(access_token)?;
-
-        let resp = tmp
-            .put_json(
-                format!(
-                    "/_matrix/client/v3/rooms/{room_id}/send/{event_type}/{txn_id}",
-                    room_id = room_id,
-                    event_type = body.event_type(),
-                    txn_id = txn_id,
-                ),
-                &body,
-            )
-            .await?;
-
-        if resp.status().is_success() {
-            return Ok(resp.json().await?);
-        }
-
-        let error = resp.json::<MatrixError>().await?;
-
-        Err(anyhow::anyhow!(error.error))
-    }
-
-    #[instrument(skip(client, access_token, body))]
-    pub async fn send_state<T: StateEventContent>(
-        client: &Client,
-        access_token: impl Into<String>,
-        room_id: &RoomId,
-        state_key: Option<String>,
-        body: T,
-    ) -> Result<SendStateResponse> {
-        let mut tmp = (*client).clone();
-        tmp.set_token(access_token)?;
-
-        let mut path = format!(
-            "/_matrix/client/v3/rooms/{room_id}/state/{event_type}",
-            room_id = room_id,
-            event_type = body.event_type(),
-        );
-
-        if let Some(state_key) = state_key {
-            path.push_str(&format!("/{state_key}", state_key = state_key))
-        }
-
-        let resp = tmp.put_json(path, &body).await?;
-
-        if resp.status().is_success() {
-            return Ok(resp.json().await?);
-        }
-
-        let error = resp.json::<MatrixError>().await?;
-
-        Err(anyhow::anyhow!(error.error))
-    }
-
-    #[instrument(skip(client, access_token, body))]
-    pub async fn send_redaction(
-        client: &Client,
-        access_token: impl Into<String>,
-        room_id: &RoomId,
-        event_id: &EventId,
-        txn_id: OwnedTransactionId,
-        body: SendRedactionBody,
-    ) -> Result<SendRedactionResponse> {
-        let mut tmp = (*client).clone();
-        tmp.set_token(access_token)?;
-
-        let resp = tmp
-            .put_json(
-                format!(
-                    "/_matrix/client/v3/rooms/{room_id}/redact/{event_id}/{txn_id}",
-                    room_id = room_id,
-                    event_id = event_id,
-                    txn_id = txn_id,
-                ),
-                &body,
-            )
-            .await?;
-
-        if resp.status().is_success() {
-            return Ok(resp.json().await?);
-        }
-
-        let error = resp.json::<MatrixError>().await?;
-
-        Err(anyhow::anyhow!(error.error))
-    }
-}
diff --git a/crates/matrix/src/client/login.rs b/crates/matrix/src/client/login.rs
deleted file mode 100644
index 6a65fba..0000000
--- a/crates/matrix/src/client/login.rs
+++ /dev/null
@@ -1,93 +0,0 @@
-use anyhow::Result;
-use serde::{Deserialize, Serialize};
-use tracing::instrument;
-
-use crate::{error::MatrixError, http::Client};
-
-#[derive(Debug, Deserialize)]
-pub struct LoginCredentials {
-    pub access_token: String,
-}
-
-#[derive(Debug, Serialize)]
-pub struct LoginCredentialsPayload {
-    pub r#type: &'static str,
-    pub user: String,
-    pub password: String,
-}
-
-#[derive(Debug, Serialize, Deserialize)]
-pub struct LoginFlow {
-    pub get_login_token: Option<bool>,
-    #[serde(rename = "type")]
-    pub kind: String,
-}
-
-#[derive(Debug, Serialize, Deserialize)]
-#[serde(transparent)]
-pub struct LoginFlows {
-    pub flows: Vec<LoginFlow>,
-}
-
-pub struct Login;
-
-impl Login {
-    /// Retrieves an access token by logging in with Username and Password
-    ///
-    /// This is equivalent to executing:
-    ///
-    /// ```ignore
-    /// curl -sS -d '{"type":"m.login.password", "user":"X", "password":"Y"}' http://server:port/_matrix/client/v3/login
-    /// ```
-    #[instrument(skip(client, username, password))]
-    pub async fn login_credentials(
-        client: &Client,
-        username: impl AsRef<str>,
-        password: impl AsRef<str>,
-    ) -> Result<LoginCredentials> {
-        let resp = client
-            .post_json(
-                "/_matrix/client/v3/login",
-                &LoginCredentialsPayload {
-                    r#type: "m.login.password",
-                    user: username.as_ref().to_string(),
-                    password: password.as_ref().to_string(),
-                },
-            )
-            .await?;
-
-        if resp.status().is_success() {
-            return Ok(resp.json().await?);
-        }
-
-        let error = resp.json::<MatrixError>().await?;
-
-        Err(anyhow::anyhow!(error.error))
-    }
-
-    #[instrument(skip(client))]
-    pub async fn get_login_flows(client: &Client) -> Result<LoginFlows> {
-        let resp = client.get("/_matrix/client/v3/login").await?;
-
-        if resp.status().is_success() {
-            return Ok(resp.json().await?);
-        }
-
-        let error = resp.json::<MatrixError>().await?;
-
-        Err(anyhow::anyhow!(error.error))
-    }
-
-    #[instrument(skip(client))]
-    pub async fn redirect_sso(client: &Client) -> Result<LoginFlows> {
-        let resp = client.get("/_matrix/client/v3/login").await?;
-
-        if resp.status().is_success() {
-            return Ok(resp.json().await?);
-        }
-
-        let error = resp.json::<MatrixError>().await?;
-
-        Err(anyhow::anyhow!(error.error))
-    }
-}
diff --git a/crates/matrix/src/client/mod.rs b/crates/matrix/src/client/mod.rs
index 43420e9..196920e 100644
--- a/crates/matrix/src/client/mod.rs
+++ b/crates/matrix/src/client/mod.rs
@@ -1,6 +1,6 @@
-pub mod error;
-pub mod events;
-pub mod login;
-pub mod mxc;
+//! This module is the root of the client-server API.
+//!
+//! reference: https://spec.matrix.org/unstable/client-server-api
+
 pub mod room;
 pub mod session;
diff --git a/crates/matrix/src/client/mxc.rs b/crates/matrix/src/client/mxc.rs
deleted file mode 100644
index 7dc669a..0000000
--- a/crates/matrix/src/client/mxc.rs
+++ /dev/null
@@ -1,184 +0,0 @@
-use std::str::FromStr;
-
-use anyhow::Result;
-use mime::Mime;
-use ruma_common::{MxcUri, OwnedMxcUri};
-use serde::{de, Deserialize, Deserializer, Serialize};
-use tracing::instrument;
-
-use chrono::{serde::ts_microseconds_option, DateTime, Utc};
-
-use crate::error::MatrixError;
-
-fn parse_mime_opt<'de, D>(d: D) -> Result<Option<Mime>, D::Error>
-where
-    D: Deserializer<'de>,
-{
-    Option::<&str>::deserialize(d)?
-        .map(<Mime as FromStr>::from_str)
-        .transpose()
-        .map_err(de::Error::custom)
-}
-
-#[derive(Debug, Serialize)]
-pub struct GetPreviewUrlQuery {
-    pub url: url::Url,
-    pub ts: DateTime<Utc>,
-}
-
-#[derive(Debug, Deserialize)]
-pub struct CreateMxcUriResponse {
-    pub content_uri: String,
-
-    #[serde(with = "ts_microseconds_option")]
-    pub unused_expires_at: Option<DateTime<Utc>>,
-}
-
-#[derive(Debug, Deserialize)]
-pub struct GetPreviewUrlResponse {
-    #[serde(rename = "matrix:image_size")]
-    pub image_size: Option<u64>,
-
-    #[serde(rename = "og:description")]
-    pub description: Option<String>,
-
-    #[serde(rename = "og:image")]
-    pub image: Option<OwnedMxcUri>,
-
-    #[serde(rename = "og:image:height")]
-    pub height: Option<u64>,
-
-    #[serde(rename = "og:image:width")]
-    pub width: Option<u64>,
-
-    #[serde(rename = "og:image:type", deserialize_with = "parse_mime_opt")]
-    pub kind: Option<mime::Mime>,
-
-    #[serde(rename = "og:title")]
-    pub title: Option<String>,
-}
-
-#[derive(Debug, Deserialize)]
-pub struct GetConfigResponse {
-    #[serde(rename = "m.upload.size")]
-    pub upload_size: Option<u64>,
-}
-
-#[derive(Debug, Serialize)]
-pub enum ResizeMethod {
-    Crop,
-    Scale,
-}
-
-pub struct MxcService;
-
-#[derive(Debug, Deserialize)]
-pub struct MxcError {
-    #[serde(flatten)]
-    pub inner: MatrixError,
-
-    pub retry_after_ms: u64,
-}
-
-impl MxcService {
-    /// Creates a new `MxcUri`, independently of the content being uploaded
-    ///
-    /// Refer: https://spec.matrix.org/v1.9/client-server-api/#post_matrixmediav1create
-    #[instrument(skip(client, access_token))]
-    pub async fn create(
-        client: &crate::http::Client,
-        access_token: impl Into<String>,
-    ) -> Result<CreateMxcUriResponse> {
-        let mut tmp = (*client).clone();
-        tmp.set_token(access_token)?;
-
-        let resp = tmp.post("/_matrix/media/v1/create").await?;
-
-        if resp.status().is_success() {
-            return Ok(resp.json().await?);
-        }
-
-        let error = resp.json::<MxcError>().await?;
-
-        Err(anyhow::anyhow!(error.inner.error))
-    }
-
-    /// Retrieve the configuration of the content repository
-    ///
-    /// Refer: https://spec.matrix.org/v1.9/client-server-api/#get_matrixmediav3config
-    #[instrument(skip(client, access_token))]
-    pub async fn get_config(
-        client: &crate::http::Client,
-        access_token: impl Into<String>,
-    ) -> Result<GetConfigResponse> {
-        let mut tmp = (*client).clone();
-        tmp.set_token(access_token)?;
-
-        let resp = tmp.get("/_matrix/media/v3/config").await?;
-
-        if resp.status().is_success() {
-            return Ok(resp.json().await?);
-        }
-
-        let error = resp.json::<MxcError>().await?;
-
-        Err(anyhow::anyhow!(error.inner.error))
-    }
-
-    /// Retrieve a URL to download content from the content repository,
-    /// optionally replacing the name of the file.
-    ///
-    /// Refer: https://spec.matrix.org/v1.9/client-server-api/#get_matrixmediav3downloadservernamemediaid
-    #[instrument(skip(client, access_token))]
-    pub async fn get_download_url(
-        client: &crate::http::Client,
-        access_token: impl Into<String>,
-        mxc_uri: &MxcUri,
-        mut base_url: url::Url,
-        file_name: Option<String>,
-    ) -> Result<url::Url> {
-        let mut tmp = (*client).clone();
-        tmp.set_token(access_token)?;
-
-        let (server_name, media_id) = mxc_uri.parts().unwrap();
-
-        let mut path = format!(
-            "/_matrix/media/v3/download/{server_name}/{media_id}",
-            server_name = server_name,
-            media_id = media_id,
-        );
-
-        if let Some(file_name) = file_name {
-            path.push_str(&format!("/{file_name}", file_name = file_name))
-        }
-
-        base_url.set_path(&path);
-
-        Ok(base_url)
-    }
-
-    ///
-    ///
-    /// Refer: https://spec.matrix.org/v1.9/client-server-api/#get_matrixmediav3preview_url
-    #[instrument(skip(client, access_token))]
-    pub async fn get_preview(
-        client: &crate::http::Client,
-        access_token: impl Into<String>,
-        query: GetPreviewUrlQuery,
-    ) -> Result<GetPreviewUrlResponse> {
-        let mut tmp = (*client).clone();
-        tmp.set_token(access_token)?;
-
-        let resp = tmp
-            .get_query("/_matrix/media/v3/preview_url".to_string(), &query)
-            .await?;
-
-        if resp.status().is_success() {
-            return Ok(resp.json().await?);
-        }
-
-        let error = resp.json::<MxcError>().await?;
-
-        Err(anyhow::anyhow!(error.inner.error))
-    }
-}
diff --git a/crates/matrix/src/client/room.rs b/crates/matrix/src/client/room.rs
index ce0d312..27a797f 100644
--- a/crates/matrix/src/client/room.rs
+++ b/crates/matrix/src/client/room.rs
@@ -1,6 +1,6 @@
-//! reference: https://spec.matrix.org/unstable/client-server-api/#rooms
-//!
 //! This module contains handlers to interact with rooms.
+//!
+//! reference: https://spec.matrix.org/unstable/client-server-api/#rooms
 
 mod ban_from_room;
 mod create_room;
diff --git a/crates/matrix/src/client/session.rs b/crates/matrix/src/client/session.rs
index 18b8249..18328e9 100644
--- a/crates/matrix/src/client/session.rs
+++ b/crates/matrix/src/client/session.rs
@@ -1,3 +1,9 @@
-mod login;
+//! This module contains handlers for user sessions.
+//!
+//! reference: https://spec.matrix.org/unstable/client-server-api/#client-authentication
+
 mod get_flows;
+mod login;
+mod register;
+mod username_available;
 mod whoami;
diff --git a/crates/matrix/src/client/session/get_flows.rs b/crates/matrix/src/client/session/get_flows.rs
index d3f6f7a..14e9a29 100644
--- a/crates/matrix/src/client/session/get_flows.rs
+++ b/crates/matrix/src/client/session/get_flows.rs
@@ -19,7 +19,7 @@ pub struct Request {}
 
 #[response(error = crate::Error)]
 pub struct Response {
-    body: Vec<LoginFlow>,
+    pub body: Vec<LoginFlow>,
 }
 
 #[derive(Clone, Debug, Deserialize)]
diff --git a/crates/matrix/src/client/session/register.rs b/crates/matrix/src/client/session/register.rs
index e662413..505e8e9 100644
--- a/crates/matrix/src/client/session/register.rs
+++ b/crates/matrix/src/client/session/register.rs
@@ -1,8 +1,7 @@
 use ruma_common::{
     api::{request, response, Metadata},
-    metadata, OwnedMxcUri, thirdparty::Medium, OwnedDeviceId, OwnedUserId,
+    metadata, OwnedDeviceId, OwnedUserId,
 };
-use serde::{Serialize, Deserialize};
 
 #[allow(dead_code)]
 const METADATA: Metadata = metadata! {
@@ -10,17 +9,15 @@ const METADATA: Metadata = metadata! {
     rate_limited: true,
     authentication: None,
     history: {
-        unstable => "",
+        unstable => "/_matrix/client/v3/register",
     }
 };
 
 #[request(error = crate::Error)]
 pub struct Request {
-    #[serde(flatten, rename = "type")]
-    pub kind: LoginType,
+    pub username: String,
 
-    #[serde(skip_serializing_if = "Option::is_none")]
-    pub identifier: Option<Identifier>,
+    pub password: String,
 
     #[serde(
         rename = "initial_device_display_name",
@@ -45,64 +42,4 @@ pub struct Response {
     pub refresh_token: Option<String>,
 
     pub user_id: OwnedUserId,
-
-    #[serde(skip_serializing_if = "Option::is_none")]
-    pub well_known: Option<WellKnown>,
-}
-
-#[derive(Clone, Debug, Serialize)]
-pub struct IdentityProvider {
-    pub id: String,
-
-    #[serde(skip_serializing_if = "String::is_empty")]
-    pub name: String,
-
-    #[serde(skip_serializing_if = "Option::is_none")]
-    pub icon: Option<OwnedMxcUri>,
-}
-
-#[derive(Clone, Debug, Serialize)]
-#[serde(tag = "type")]
-pub enum LoginType {
-    #[serde(rename = "m.login.password")]
-    Password { password: String },
-
-    #[serde(rename = "m.login.token")]
-    Token { token: String },
-
-    #[serde(rename = "m.login.sso")]
-    Sso {
-        #[serde(skip_serializing_if = "<[_]>::is_empty")]
-        identity_providers: Vec<IdentityProvider>,
-    },
-
-    #[serde(rename = "m.login.application_service")]
-    ApplicationService,
-}
-
-#[derive(Clone, Debug, Serialize)]
-#[serde(tag = "type")]
-pub enum Identifier {
-    #[serde(rename = "m.id.user")]
-    User { user: String },
-
-    #[serde(rename = "m.id.thirdparty")]
-    ThirdParty { medium: Medium, address: String },
-
-    #[serde(rename = "m.id.phone")]
-    Phone { country: String, phone: String },
-}
-
-#[derive(Clone, Debug, Deserialize)]
-pub struct BaseUrl {
-    pub base_url: url::Url,
-}
-
-#[derive(Clone, Debug, Deserialize)]
-pub struct WellKnown {
-    #[serde(rename = "m.homeserver")]
-    pub homeserver: BaseUrl,
-
-    #[serde(rename = "m.identity_server")]
-    pub identity_server: BaseUrl,
 }
diff --git a/crates/matrix/src/client/session/username_available.rs b/crates/matrix/src/client/session/username_available.rs
new file mode 100644
index 0000000..e380f6f
--- /dev/null
+++ b/crates/matrix/src/client/session/username_available.rs
@@ -0,0 +1,24 @@
+use ruma_common::{
+    api::{request, response, Metadata},
+    metadata,
+};
+
+#[allow(dead_code)]
+const METADATA: Metadata = metadata! {
+    method: POST,
+    rate_limited: true,
+    authentication: None,
+    history: {
+        unstable => "/_matrix/client/v3/register/available",
+    }
+};
+
+#[request(error = crate::Error)]
+pub struct Request {
+    pub username: String,
+}
+
+#[response(error = crate::Error)]
+pub struct Response {
+    pub available: bool,
+}
diff --git a/crates/matrix/src/lib.rs b/crates/matrix/src/lib.rs
index 2b2848e..ace15fb 100644
--- a/crates/matrix/src/lib.rs
+++ b/crates/matrix/src/lib.rs
@@ -1,3 +1,11 @@
+//! This library deals with forwarding Matrix requests to the server.
+//! Comments have been used sparingly as the specification contains all the technical details.
+
+//! We rely on `ruma` to abstract away the boilerplate introduced by HTTP requests,
+//! without sacrificing flexibility by defining our own request and response types.
+//!
+//! reference: https://docs.ruma.io/ruma_common/api/index.html
+
 pub mod admin;
 pub mod client;