diff --git a/clippy.toml b/clippy.toml
index 61c5c04f..a300ae05 100644
--- a/clippy.toml
+++ b/clippy.toml
@@ -1,4 +1,4 @@
-doc-valid-idents = ["OpenID", "OAuth", ".."]
+doc-valid-idents = ["OpenID", "OAuth", "..", "PostgreSQL"]
 
 disallowed-methods = [
     { path = "rand::thread_rng", reason = "do not create rngs on the fly, pass them as parameters" },
diff --git a/crates/axum-utils/src/client_authorization.rs b/crates/axum-utils/src/client_authorization.rs
index 67930c3f..6f5b3e27 100644
--- a/crates/axum-utils/src/client_authorization.rs
+++ b/crates/axum-utils/src/client_authorization.rs
@@ -31,7 +31,7 @@ use mas_http::HttpServiceExt;
 use mas_iana::oauth::OAuthClientAuthenticationMethod;
 use mas_jose::{jwk::PublicJsonWebKeySet, jwt::Jwt};
 use mas_keystore::Encrypter;
-use mas_storage::{oauth2::OAuth2ClientRepository, Repository};
+use mas_storage::{oauth2::OAuth2ClientRepository, RepositoryAccess};
 use serde::{de::DeserializeOwned, Deserialize};
 use serde_json::Value;
 use thiserror::Error;
@@ -74,7 +74,7 @@ pub enum Credentials {
 impl Credentials {
     pub async fn fetch<E>(
         &self,
-        repo: &mut (impl Repository<Error = E> + ?Sized),
+        repo: &mut (impl RepositoryAccess<Error = E> + ?Sized),
     ) -> Result<Option<Client>, E> {
         let client_id = match self {
             Credentials::None { client_id }
diff --git a/crates/axum-utils/src/session.rs b/crates/axum-utils/src/session.rs
index 5e966152..c4fece7b 100644
--- a/crates/axum-utils/src/session.rs
+++ b/crates/axum-utils/src/session.rs
@@ -14,7 +14,7 @@
 
 use axum_extra::extract::cookie::{Cookie, PrivateCookieJar};
 use mas_data_model::BrowserSession;
-use mas_storage::{user::BrowserSessionRepository, Repository};
+use mas_storage::{user::BrowserSessionRepository, RepositoryAccess};
 use serde::{Deserialize, Serialize};
 use ulid::Ulid;
 
@@ -45,7 +45,7 @@ impl SessionInfo {
     /// Load the [`BrowserSession`] from database
     pub async fn load_session<E>(
         &self,
-        repo: &mut (impl Repository<Error = E> + ?Sized),
+        repo: &mut impl RepositoryAccess<Error = E>,
     ) -> Result<Option<BrowserSession>, E> {
         let session_id = if let Some(id) = self.current {
             id
diff --git a/crates/axum-utils/src/user_authorization.rs b/crates/axum-utils/src/user_authorization.rs
index 2d37c40c..c9bc537c 100644
--- a/crates/axum-utils/src/user_authorization.rs
+++ b/crates/axum-utils/src/user_authorization.rs
@@ -29,7 +29,7 @@ use http::{header::WWW_AUTHENTICATE, HeaderMap, HeaderValue, Request, StatusCode
 use mas_data_model::Session;
 use mas_storage::{
     oauth2::{OAuth2AccessTokenRepository, OAuth2SessionRepository},
-    Clock, Repository,
+    Clock, RepositoryAccess,
 };
 use serde::{de::DeserializeOwned, Deserialize};
 use thiserror::Error;
@@ -53,7 +53,7 @@ enum AccessToken {
 impl AccessToken {
     async fn fetch<E>(
         &self,
-        repo: &mut (impl Repository<Error = E> + ?Sized),
+        repo: &mut impl RepositoryAccess<Error = E>,
     ) -> Result<(mas_data_model::AccessToken, Session), AuthorizationVerificationError<E>> {
         let token = match self {
             AccessToken::Form(t) | AccessToken::Header(t) => t,
@@ -86,7 +86,7 @@ impl<F: Send> UserAuthorization<F> {
     // TODO: take scopes to validate as parameter
     pub async fn protected_form<E>(
         self,
-        repo: &mut (impl Repository<Error = E> + ?Sized),
+        repo: &mut impl RepositoryAccess<Error = E>,
         clock: &impl Clock,
     ) -> Result<(Session, F), AuthorizationVerificationError<E>> {
         let form = match self.form {
@@ -106,7 +106,7 @@ impl<F: Send> UserAuthorization<F> {
     // TODO: take scopes to validate as parameter
     pub async fn protected<E>(
         self,
-        repo: &mut (impl Repository<Error = E> + ?Sized),
+        repo: &mut impl RepositoryAccess<Error = E>,
         clock: &impl Clock,
     ) -> Result<Session, AuthorizationVerificationError<E>> {
         let (token, session) = self.access_token.fetch(repo).await?;
diff --git a/crates/cli/src/commands/manage.rs b/crates/cli/src/commands/manage.rs
index 4e74569a..b685a167 100644
--- a/crates/cli/src/commands/manage.rs
+++ b/crates/cli/src/commands/manage.rs
@@ -21,7 +21,7 @@ use mas_storage::{
     oauth2::OAuth2ClientRepository,
     upstream_oauth2::UpstreamOAuthProviderRepository,
     user::{UserEmailRepository, UserPasswordRepository, UserRepository},
-    Repository, SystemClock,
+    Repository, RepositoryAccess, SystemClock,
 };
 use mas_storage_pg::PgRepository;
 use oauth2_types::scope::Scope;
diff --git a/crates/data-model/src/compat/device.rs b/crates/data-model/src/compat/device.rs
index 84bdd067..eebfd9ed 100644
--- a/crates/data-model/src/compat/device.rs
+++ b/crates/data-model/src/compat/device.rs
@@ -15,7 +15,7 @@
 use oauth2_types::scope::ScopeToken;
 use rand::{
     distributions::{Alphanumeric, DistString},
-    Rng,
+    RngCore,
 };
 use serde::Serialize;
 use thiserror::Error;
@@ -48,7 +48,7 @@ impl Device {
     }
 
     /// Generate a random device ID
-    pub fn generate<R: Rng + ?Sized>(rng: &mut R) -> Self {
+    pub fn generate<R: RngCore + ?Sized>(rng: &mut R) -> Self {
         let id: String = Alphanumeric.sample_string(rng, DEVICE_ID_LENGTH);
         Self { id }
     }
diff --git a/crates/handlers/src/views/account/emails/mod.rs b/crates/handlers/src/views/account/emails/mod.rs
index 83038337..ad997e0d 100644
--- a/crates/handlers/src/views/account/emails/mod.rs
+++ b/crates/handlers/src/views/account/emails/mod.rs
@@ -28,7 +28,9 @@ use mas_data_model::{BrowserSession, User, UserEmail};
 use mas_email::Mailer;
 use mas_keystore::Encrypter;
 use mas_router::Route;
-use mas_storage::{user::UserEmailRepository, BoxClock, BoxRepository, BoxRng, Clock, Repository};
+use mas_storage::{
+    user::UserEmailRepository, BoxClock, BoxRepository, BoxRng, Clock, RepositoryAccess,
+};
 use mas_templates::{AccountEmailsContext, EmailVerificationContext, TemplateContext, Templates};
 use rand::{distributions::Uniform, Rng};
 use serde::Deserialize;
@@ -71,7 +73,7 @@ async fn render<E: std::error::Error>(
     templates: Templates,
     session: BrowserSession,
     cookie_jar: PrivateCookieJar<Encrypter>,
-    repo: &mut (impl Repository<Error = E> + ?Sized),
+    repo: &mut impl RepositoryAccess<Error = E>,
 ) -> Result<Response, FancyError> {
     let (csrf_token, cookie_jar) = cookie_jar.csrf_token(clock, rng);
 
@@ -88,7 +90,7 @@ async fn render<E: std::error::Error>(
 
 async fn start_email_verification<E: std::error::Error + Send + Sync + 'static>(
     mailer: &Mailer,
-    repo: &mut (impl Repository<Error = E> + ?Sized),
+    repo: &mut impl RepositoryAccess<Error = E>,
     mut rng: impl Rng + Send,
     clock: &impl Clock,
     user: &User,
diff --git a/crates/handlers/src/views/login.rs b/crates/handlers/src/views/login.rs
index 2836eee3..3083eae0 100644
--- a/crates/handlers/src/views/login.rs
+++ b/crates/handlers/src/views/login.rs
@@ -26,7 +26,7 @@ use mas_keystore::Encrypter;
 use mas_storage::{
     upstream_oauth2::UpstreamOAuthProviderRepository,
     user::{BrowserSessionRepository, UserPasswordRepository, UserRepository},
-    BoxClock, BoxRepository, BoxRng, Clock, Repository,
+    BoxClock, BoxRepository, BoxRng, Clock, RepositoryAccess,
 };
 use mas_templates::{
     FieldError, FormError, LoginContext, LoginFormField, TemplateContext, Templates, ToFormState,
@@ -161,7 +161,7 @@ pub(crate) async fn post(
 // TODO: move that logic elsewhere?
 async fn login(
     password_manager: PasswordManager,
-    repo: &mut (impl Repository + ?Sized),
+    repo: &mut impl RepositoryAccess,
     mut rng: impl Rng + CryptoRng + Send,
     clock: &impl Clock,
     username: &str,
@@ -235,7 +235,7 @@ async fn render(
     ctx: LoginContext,
     action: OptionalPostAuthAction,
     csrf_token: CsrfToken,
-    repo: &mut (impl Repository + ?Sized),
+    repo: &mut impl RepositoryAccess,
     templates: &Templates,
 ) -> Result<String, FancyError> {
     let next = action.load_context(repo).await?;
diff --git a/crates/handlers/src/views/register.rs b/crates/handlers/src/views/register.rs
index ad1ff378..64e30af7 100644
--- a/crates/handlers/src/views/register.rs
+++ b/crates/handlers/src/views/register.rs
@@ -33,7 +33,7 @@ use mas_policy::PolicyFactory;
 use mas_router::Route;
 use mas_storage::{
     user::{BrowserSessionRepository, UserEmailRepository, UserPasswordRepository, UserRepository},
-    BoxClock, BoxRepository, BoxRng, Repository,
+    BoxClock, BoxRepository, BoxRng, RepositoryAccess,
 };
 use mas_templates::{
     EmailVerificationContext, FieldError, FormError, RegisterContext, RegisterFormField,
@@ -233,7 +233,7 @@ async fn render(
     ctx: RegisterContext,
     action: OptionalPostAuthAction,
     csrf_token: CsrfToken,
-    repo: &mut (impl Repository + ?Sized),
+    repo: &mut impl RepositoryAccess,
     templates: &Templates,
 ) -> Result<String, FancyError> {
     let next = action.load_context(repo).await?;
diff --git a/crates/handlers/src/views/shared.rs b/crates/handlers/src/views/shared.rs
index b2946084..69fdf901 100644
--- a/crates/handlers/src/views/shared.rs
+++ b/crates/handlers/src/views/shared.rs
@@ -18,7 +18,7 @@ use mas_storage::{
     compat::CompatSsoLoginRepository,
     oauth2::OAuth2AuthorizationGrantRepository,
     upstream_oauth2::{UpstreamOAuthLinkRepository, UpstreamOAuthProviderRepository},
-    Repository,
+    RepositoryAccess,
 };
 use mas_templates::{PostAuthContext, PostAuthContextInner};
 use serde::{Deserialize, Serialize};
@@ -42,7 +42,7 @@ impl OptionalPostAuthAction {
 
     pub async fn load_context<'a>(
         &'a self,
-        repo: &'a mut (impl Repository + ?Sized),
+        repo: &'a mut impl RepositoryAccess,
     ) -> anyhow::Result<Option<PostAuthContext>> {
         let Some(action) = self.post_auth_action.clone() else { return Ok(None) };
         let ctx = match action {
diff --git a/crates/storage-pg/src/compat/mod.rs b/crates/storage-pg/src/compat/mod.rs
index 9b340756..5d99f332 100644
--- a/crates/storage-pg/src/compat/mod.rs
+++ b/crates/storage-pg/src/compat/mod.rs
@@ -32,7 +32,7 @@ mod tests {
             CompatAccessTokenRepository, CompatRefreshTokenRepository, CompatSessionRepository,
         },
         user::UserRepository,
-        Clock, Repository,
+        Clock, Repository, RepositoryAccess,
     };
     use rand::SeedableRng;
     use rand_chacha::ChaChaRng;
diff --git a/crates/storage-pg/src/lib.rs b/crates/storage-pg/src/lib.rs
index 459c8c3b..08c89db2 100644
--- a/crates/storage-pg/src/lib.rs
+++ b/crates/storage-pg/src/lib.rs
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//! Interactions with the database
+//! An implementation of the storage traits for a PostgreSQL database
 
 #![forbid(unsafe_code)]
 #![deny(
diff --git a/crates/storage-pg/src/repository.rs b/crates/storage-pg/src/repository.rs
index 6448b61a..0f1fdfb4 100644
--- a/crates/storage-pg/src/repository.rs
+++ b/crates/storage-pg/src/repository.rs
@@ -27,7 +27,7 @@ use mas_storage::{
         UpstreamOAuthSessionRepository,
     },
     user::{BrowserSessionRepository, UserEmailRepository, UserPasswordRepository, UserRepository},
-    Repository,
+    Repository, RepositoryAccess, RepositoryTransaction,
 };
 use sqlx::{PgPool, Postgres, Transaction};
 
@@ -62,7 +62,9 @@ impl PgRepository {
     }
 }
 
-impl Repository for PgRepository {
+impl Repository<DatabaseError> for PgRepository {}
+
+impl RepositoryTransaction for PgRepository {
     type Error = DatabaseError;
 
     fn save(self: Box<Self>) -> BoxFuture<'static, Result<(), Self::Error>> {
@@ -72,6 +74,10 @@ impl Repository for PgRepository {
     fn cancel(self: Box<Self>) -> BoxFuture<'static, Result<(), Self::Error>> {
         self.txn.rollback().map_err(DatabaseError::from).boxed()
     }
+}
+
+impl RepositoryAccess for PgRepository {
+    type Error = DatabaseError;
 
     fn upstream_oauth_link<'c>(
         &'c mut self,
diff --git a/crates/storage-pg/src/upstream_oauth2/mod.rs b/crates/storage-pg/src/upstream_oauth2/mod.rs
index af631f15..9ff7699e 100644
--- a/crates/storage-pg/src/upstream_oauth2/mod.rs
+++ b/crates/storage-pg/src/upstream_oauth2/mod.rs
@@ -31,7 +31,7 @@ mod tests {
             UpstreamOAuthSessionRepository,
         },
         user::UserRepository,
-        Pagination, Repository,
+        Pagination, RepositoryAccess,
     };
     use oauth2_types::scope::{Scope, OPENID};
     use rand::SeedableRng;
diff --git a/crates/storage-pg/src/user/tests.rs b/crates/storage-pg/src/user/tests.rs
index 7c3eab37..29f828ab 100644
--- a/crates/storage-pg/src/user/tests.rs
+++ b/crates/storage-pg/src/user/tests.rs
@@ -16,7 +16,7 @@ use chrono::Duration;
 use mas_storage::{
     clock::MockClock,
     user::{BrowserSessionRepository, UserEmailRepository, UserPasswordRepository, UserRepository},
-    Repository,
+    Repository, RepositoryAccess,
 };
 use rand::SeedableRng;
 use rand_chacha::ChaChaRng;
diff --git a/crates/storage/src/lib.rs b/crates/storage/src/lib.rs
index aa1db0af..69bc2881 100644
--- a/crates/storage/src/lib.rs
+++ b/crates/storage/src/lib.rs
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//! Interactions with the database
+//! Interactions with the storage backend
 
 #![forbid(unsafe_code)]
 #![deny(
@@ -42,20 +42,25 @@ pub mod user;
 pub use self::{
     clock::{Clock, SystemClock},
     pagination::{Page, Pagination},
-    repository::{BoxRepository, Repository, RepositoryError},
+    repository::{
+        BoxRepository, Repository, RepositoryAccess, RepositoryError, RepositoryTransaction,
+    },
 };
 
-pub struct MapErr<Repository, Mapper> {
-    inner: Repository,
-    mapper: Mapper,
+/// A wrapper which is used to map the error type of a repository to another
+pub struct MapErr<R, F> {
+    inner: R,
+    mapper: F,
 }
 
-impl<Repository, Mapper> MapErr<Repository, Mapper> {
-    fn new(inner: Repository, mapper: Mapper) -> Self {
+impl<R, F> MapErr<R, F> {
+    fn new(inner: R, mapper: F) -> Self {
         Self { inner, mapper }
     }
 }
 
+/// A macro to implement a repository trait for the [`MapErr`] wrapper and for
+/// [`Box<R>`]
 #[macro_export]
 macro_rules! repository_impl {
     ($repo_trait:ident:
diff --git a/crates/storage/src/repository.rs b/crates/storage/src/repository.rs
index d6772b9a..f023e469 100644
--- a/crates/storage/src/repository.rs
+++ b/crates/storage/src/repository.rs
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use futures_util::{future::BoxFuture, FutureExt, TryFutureExt};
+use futures_util::future::BoxFuture;
 use thiserror::Error;
 
 use crate::{
@@ -32,83 +32,27 @@ use crate::{
     MapErr,
 };
 
-pub trait Repository: Send {
-    type Error: std::error::Error + Send + Sync + 'static;
+/// A [`Repository`] helps interacting with the underlying storage backend.
+pub trait Repository<E>:
+    RepositoryAccess<Error = E> + RepositoryTransaction<Error = E> + Send
+where
+    E: std::error::Error + Send + Sync + 'static,
+{
+    /// Construct a (boxed) typed-erased repository
+    fn boxed(self) -> BoxRepository<E>
+    where
+        Self: Sync + Sized + 'static,
+    {
+        Box::new(self)
+    }
 
+    /// Map the error type of all the methods of a [`Repository`]
     fn map_err<Mapper>(self, mapper: Mapper) -> MapErr<Self, Mapper>
     where
         Self: Sized,
     {
         MapErr::new(self, mapper)
     }
-
-    fn boxed(self) -> BoxRepository<Self::Error>
-    where
-        Self: Sized + Sync + 'static,
-    {
-        Box::new(self)
-    }
-
-    fn save(self: Box<Self>) -> BoxFuture<'static, Result<(), Self::Error>>;
-    fn cancel(self: Box<Self>) -> BoxFuture<'static, Result<(), Self::Error>>;
-
-    fn upstream_oauth_link<'c>(
-        &'c mut self,
-    ) -> Box<dyn UpstreamOAuthLinkRepository<Error = Self::Error> + 'c>;
-
-    fn upstream_oauth_provider<'c>(
-        &'c mut self,
-    ) -> Box<dyn UpstreamOAuthProviderRepository<Error = Self::Error> + 'c>;
-
-    fn upstream_oauth_session<'c>(
-        &'c mut self,
-    ) -> Box<dyn UpstreamOAuthSessionRepository<Error = Self::Error> + 'c>;
-
-    fn user<'c>(&'c mut self) -> Box<dyn UserRepository<Error = Self::Error> + 'c>;
-
-    fn user_email<'c>(&'c mut self) -> Box<dyn UserEmailRepository<Error = Self::Error> + 'c>;
-
-    fn user_password<'c>(&'c mut self)
-        -> Box<dyn UserPasswordRepository<Error = Self::Error> + 'c>;
-
-    fn browser_session<'c>(
-        &'c mut self,
-    ) -> Box<dyn BrowserSessionRepository<Error = Self::Error> + 'c>;
-
-    fn oauth2_client<'c>(&'c mut self)
-        -> Box<dyn OAuth2ClientRepository<Error = Self::Error> + 'c>;
-
-    fn oauth2_authorization_grant<'c>(
-        &'c mut self,
-    ) -> Box<dyn OAuth2AuthorizationGrantRepository<Error = Self::Error> + 'c>;
-
-    fn oauth2_session<'c>(
-        &'c mut self,
-    ) -> Box<dyn OAuth2SessionRepository<Error = Self::Error> + 'c>;
-
-    fn oauth2_access_token<'c>(
-        &'c mut self,
-    ) -> Box<dyn OAuth2AccessTokenRepository<Error = Self::Error> + 'c>;
-
-    fn oauth2_refresh_token<'c>(
-        &'c mut self,
-    ) -> Box<dyn OAuth2RefreshTokenRepository<Error = Self::Error> + 'c>;
-
-    fn compat_session<'c>(
-        &'c mut self,
-    ) -> Box<dyn CompatSessionRepository<Error = Self::Error> + 'c>;
-
-    fn compat_sso_login<'c>(
-        &'c mut self,
-    ) -> Box<dyn CompatSsoLoginRepository<Error = Self::Error> + 'c>;
-
-    fn compat_access_token<'c>(
-        &'c mut self,
-    ) -> Box<dyn CompatAccessTokenRepository<Error = Self::Error> + 'c>;
-
-    fn compat_refresh_token<'c>(
-        &'c mut self,
-    ) -> Box<dyn CompatRefreshTokenRepository<Error = Self::Error> + 'c>;
 }
 
 /// An opaque, type-erased error
@@ -119,6 +63,7 @@ pub struct RepositoryError {
 }
 
 impl RepositoryError {
+    /// Construct a [`RepositoryError`] from any error kind
     pub fn from_error<E>(value: E) -> Self
     where
         E: std::error::Error + Send + Sync + 'static,
@@ -129,251 +74,386 @@ impl RepositoryError {
     }
 }
 
-pub type BoxRepository<E = RepositoryError> =
-    Box<dyn Repository<Error = E> + Send + Sync + 'static>;
+/// A type-erased [`Repository`]
+pub type BoxRepository<E = RepositoryError> = Box<dyn Repository<E> + Send + Sync + 'static>;
 
-impl<R, F, E> Repository for crate::MapErr<R, F>
-where
-    R: Repository,
-    R::Error: 'static,
-    F: FnMut(R::Error) -> E + Send + Sync + 'static,
-    E: std::error::Error + Send + Sync + 'static,
-{
-    type Error = E;
+/// A [`RepositoryTransaction`] can be saved or cancelled, after a series
+/// of operations.
+pub trait RepositoryTransaction {
+    /// The error type used by the [`Self::save`] and [`Self::cancel`] functions
+    type Error;
 
-    fn save(self: Box<Self>) -> BoxFuture<'static, Result<(), Self::Error>> {
-        Box::new(self.inner).save().map_err(self.mapper).boxed()
-    }
+    /// Commit the transaction
+    ///
+    /// # Errors
+    ///
+    /// Returns an error if the underlying storage backend failed to commit the
+    /// transaction.
+    fn save(self: Box<Self>) -> BoxFuture<'static, Result<(), Self::Error>>;
 
-    fn cancel(self: Box<Self>) -> BoxFuture<'static, Result<(), Self::Error>> {
-        Box::new(self.inner).cancel().map_err(self.mapper).boxed()
-    }
-
-    fn upstream_oauth_link<'c>(
-        &'c mut self,
-    ) -> Box<dyn UpstreamOAuthLinkRepository<Error = Self::Error> + 'c> {
-        Box::new(MapErr::new(
-            self.inner.upstream_oauth_link(),
-            &mut self.mapper,
-        ))
-    }
-
-    fn upstream_oauth_provider<'c>(
-        &'c mut self,
-    ) -> Box<dyn UpstreamOAuthProviderRepository<Error = Self::Error> + 'c> {
-        Box::new(MapErr::new(
-            self.inner.upstream_oauth_provider(),
-            &mut self.mapper,
-        ))
-    }
-
-    fn upstream_oauth_session<'c>(
-        &'c mut self,
-    ) -> Box<dyn UpstreamOAuthSessionRepository<Error = Self::Error> + 'c> {
-        Box::new(MapErr::new(
-            self.inner.upstream_oauth_session(),
-            &mut self.mapper,
-        ))
-    }
-
-    fn user<'c>(&'c mut self) -> Box<dyn UserRepository<Error = Self::Error> + 'c> {
-        Box::new(MapErr::new(self.inner.user(), &mut self.mapper))
-    }
-
-    fn user_email<'c>(&'c mut self) -> Box<dyn UserEmailRepository<Error = Self::Error> + 'c> {
-        Box::new(MapErr::new(self.inner.user_email(), &mut self.mapper))
-    }
-
-    fn user_password<'c>(
-        &'c mut self,
-    ) -> Box<dyn UserPasswordRepository<Error = Self::Error> + 'c> {
-        Box::new(MapErr::new(self.inner.user_password(), &mut self.mapper))
-    }
-
-    fn browser_session<'c>(
-        &'c mut self,
-    ) -> Box<dyn BrowserSessionRepository<Error = Self::Error> + 'c> {
-        Box::new(MapErr::new(self.inner.browser_session(), &mut self.mapper))
-    }
-
-    fn oauth2_client<'c>(
-        &'c mut self,
-    ) -> Box<dyn OAuth2ClientRepository<Error = Self::Error> + 'c> {
-        Box::new(MapErr::new(self.inner.oauth2_client(), &mut self.mapper))
-    }
-
-    fn oauth2_authorization_grant<'c>(
-        &'c mut self,
-    ) -> Box<dyn OAuth2AuthorizationGrantRepository<Error = Self::Error> + 'c> {
-        Box::new(MapErr::new(
-            self.inner.oauth2_authorization_grant(),
-            &mut self.mapper,
-        ))
-    }
-
-    fn oauth2_session<'c>(
-        &'c mut self,
-    ) -> Box<dyn OAuth2SessionRepository<Error = Self::Error> + 'c> {
-        Box::new(MapErr::new(self.inner.oauth2_session(), &mut self.mapper))
-    }
-
-    fn oauth2_access_token<'c>(
-        &'c mut self,
-    ) -> Box<dyn OAuth2AccessTokenRepository<Error = Self::Error> + 'c> {
-        Box::new(MapErr::new(
-            self.inner.oauth2_access_token(),
-            &mut self.mapper,
-        ))
-    }
-
-    fn oauth2_refresh_token<'c>(
-        &'c mut self,
-    ) -> Box<dyn OAuth2RefreshTokenRepository<Error = Self::Error> + 'c> {
-        Box::new(MapErr::new(
-            self.inner.oauth2_refresh_token(),
-            &mut self.mapper,
-        ))
-    }
-
-    fn compat_session<'c>(
-        &'c mut self,
-    ) -> Box<dyn CompatSessionRepository<Error = Self::Error> + 'c> {
-        Box::new(MapErr::new(self.inner.compat_session(), &mut self.mapper))
-    }
-
-    fn compat_sso_login<'c>(
-        &'c mut self,
-    ) -> Box<dyn CompatSsoLoginRepository<Error = Self::Error> + 'c> {
-        Box::new(MapErr::new(self.inner.compat_sso_login(), &mut self.mapper))
-    }
-
-    fn compat_access_token<'c>(
-        &'c mut self,
-    ) -> Box<dyn CompatAccessTokenRepository<Error = Self::Error> + 'c> {
-        Box::new(MapErr::new(
-            self.inner.compat_access_token(),
-            &mut self.mapper,
-        ))
-    }
-
-    fn compat_refresh_token<'c>(
-        &'c mut self,
-    ) -> Box<dyn CompatRefreshTokenRepository<Error = Self::Error> + 'c> {
-        Box::new(MapErr::new(
-            self.inner.compat_refresh_token(),
-            &mut self.mapper,
-        ))
-    }
+    /// Rollback the transaction
+    ///
+    /// # Errors
+    ///
+    /// Returns an error if the underlying storage backend failed to rollback
+    /// the transaction.
+    fn cancel(self: Box<Self>) -> BoxFuture<'static, Result<(), Self::Error>>;
 }
 
-impl<R: Repository + ?Sized> Repository for Box<R> {
-    type Error = R::Error;
-
-    fn save(self: Box<Self>) -> BoxFuture<'static, Result<(), Self::Error>>
-    where
-        Self: Sized,
-    {
-        // This shouldn't be callable?
-        unimplemented!()
-    }
-
-    fn cancel(self: Box<Self>) -> BoxFuture<'static, Result<(), Self::Error>>
-    where
-        Self: Sized,
-    {
-        // This shouldn't be callable?
-        unimplemented!()
-    }
+/// Access the various repositories the backend implements.
+pub trait RepositoryAccess: Send {
+    /// The backend-specific error type used by each repository.
+    type Error: std::error::Error + Send + Sync + 'static;
 
+    /// Get an [`UpstreamOAuthLinkRepository`]
     fn upstream_oauth_link<'c>(
         &'c mut self,
-    ) -> Box<dyn UpstreamOAuthLinkRepository<Error = Self::Error> + 'c> {
-        (**self).upstream_oauth_link()
-    }
+    ) -> Box<dyn UpstreamOAuthLinkRepository<Error = Self::Error> + 'c>;
 
+    /// Get an [`UpstreamOAuthProviderRepository`]
     fn upstream_oauth_provider<'c>(
         &'c mut self,
-    ) -> Box<dyn UpstreamOAuthProviderRepository<Error = Self::Error> + 'c> {
-        (**self).upstream_oauth_provider()
-    }
+    ) -> Box<dyn UpstreamOAuthProviderRepository<Error = Self::Error> + 'c>;
 
+    /// Get an [`UpstreamOAuthSessionRepository`]
     fn upstream_oauth_session<'c>(
         &'c mut self,
-    ) -> Box<dyn UpstreamOAuthSessionRepository<Error = Self::Error> + 'c> {
-        (**self).upstream_oauth_session()
-    }
+    ) -> Box<dyn UpstreamOAuthSessionRepository<Error = Self::Error> + 'c>;
 
-    fn user<'c>(&'c mut self) -> Box<dyn UserRepository<Error = Self::Error> + 'c> {
-        (**self).user()
-    }
+    /// Get an [`UserRepository`]
+    fn user<'c>(&'c mut self) -> Box<dyn UserRepository<Error = Self::Error> + 'c>;
 
-    fn user_email<'c>(&'c mut self) -> Box<dyn UserEmailRepository<Error = Self::Error> + 'c> {
-        (**self).user_email()
-    }
+    /// Get an [`UserEmailRepository`]
+    fn user_email<'c>(&'c mut self) -> Box<dyn UserEmailRepository<Error = Self::Error> + 'c>;
 
-    fn user_password<'c>(
-        &'c mut self,
-    ) -> Box<dyn UserPasswordRepository<Error = Self::Error> + 'c> {
-        (**self).user_password()
-    }
+    /// Get an [`UserPasswordRepository`]
+    fn user_password<'c>(&'c mut self)
+        -> Box<dyn UserPasswordRepository<Error = Self::Error> + 'c>;
 
+    /// Get a [`BrowserSessionRepository`]
     fn browser_session<'c>(
         &'c mut self,
-    ) -> Box<dyn BrowserSessionRepository<Error = Self::Error> + 'c> {
-        (**self).browser_session()
-    }
+    ) -> Box<dyn BrowserSessionRepository<Error = Self::Error> + 'c>;
 
-    fn oauth2_client<'c>(
-        &'c mut self,
-    ) -> Box<dyn OAuth2ClientRepository<Error = Self::Error> + 'c> {
-        (**self).oauth2_client()
-    }
+    /// Get an [`OAuth2ClientRepository`]
+    fn oauth2_client<'c>(&'c mut self)
+        -> Box<dyn OAuth2ClientRepository<Error = Self::Error> + 'c>;
 
+    /// Get an [`OAuth2AuthorizationGrantRepository`]
     fn oauth2_authorization_grant<'c>(
         &'c mut self,
-    ) -> Box<dyn OAuth2AuthorizationGrantRepository<Error = Self::Error> + 'c> {
-        (**self).oauth2_authorization_grant()
-    }
+    ) -> Box<dyn OAuth2AuthorizationGrantRepository<Error = Self::Error> + 'c>;
 
+    /// Get an [`OAuth2SessionRepository`]
     fn oauth2_session<'c>(
         &'c mut self,
-    ) -> Box<dyn OAuth2SessionRepository<Error = Self::Error> + 'c> {
-        (**self).oauth2_session()
-    }
+    ) -> Box<dyn OAuth2SessionRepository<Error = Self::Error> + 'c>;
 
+    /// Get an [`OAuth2AccessTokenRepository`]
     fn oauth2_access_token<'c>(
         &'c mut self,
-    ) -> Box<dyn OAuth2AccessTokenRepository<Error = Self::Error> + 'c> {
-        (**self).oauth2_access_token()
-    }
+    ) -> Box<dyn OAuth2AccessTokenRepository<Error = Self::Error> + 'c>;
 
+    /// Get an [`OAuth2RefreshTokenRepository`]
     fn oauth2_refresh_token<'c>(
         &'c mut self,
-    ) -> Box<dyn OAuth2RefreshTokenRepository<Error = Self::Error> + 'c> {
-        (**self).oauth2_refresh_token()
-    }
+    ) -> Box<dyn OAuth2RefreshTokenRepository<Error = Self::Error> + 'c>;
 
+    /// Get a [`CompatSessionRepository`]
     fn compat_session<'c>(
         &'c mut self,
-    ) -> Box<dyn CompatSessionRepository<Error = Self::Error> + 'c> {
-        (**self).compat_session()
-    }
+    ) -> Box<dyn CompatSessionRepository<Error = Self::Error> + 'c>;
 
+    /// Get a [`CompatSsoLoginRepository`]
     fn compat_sso_login<'c>(
         &'c mut self,
-    ) -> Box<dyn CompatSsoLoginRepository<Error = Self::Error> + 'c> {
-        (**self).compat_sso_login()
-    }
+    ) -> Box<dyn CompatSsoLoginRepository<Error = Self::Error> + 'c>;
 
+    /// Get a [`CompatAccessTokenRepository`]
     fn compat_access_token<'c>(
         &'c mut self,
-    ) -> Box<dyn CompatAccessTokenRepository<Error = Self::Error> + 'c> {
-        (**self).compat_access_token()
-    }
+    ) -> Box<dyn CompatAccessTokenRepository<Error = Self::Error> + 'c>;
 
+    /// Get a [`CompatRefreshTokenRepository`]
     fn compat_refresh_token<'c>(
         &'c mut self,
-    ) -> Box<dyn CompatRefreshTokenRepository<Error = Self::Error> + 'c> {
-        (**self).compat_refresh_token()
+    ) -> Box<dyn CompatRefreshTokenRepository<Error = Self::Error> + 'c>;
+}
+
+/// Implementations of the [`RepositoryAccess`], [`RepositoryTransaction`] and
+/// [`Repository`] for the [`MapErr`] wrapper and [`Box<R>`]
+mod impls {
+    use futures_util::{future::BoxFuture, FutureExt, TryFutureExt};
+
+    use super::RepositoryAccess;
+    use crate::{
+        compat::{
+            CompatAccessTokenRepository, CompatRefreshTokenRepository, CompatSessionRepository,
+            CompatSsoLoginRepository,
+        },
+        oauth2::{
+            OAuth2AccessTokenRepository, OAuth2AuthorizationGrantRepository,
+            OAuth2ClientRepository, OAuth2RefreshTokenRepository, OAuth2SessionRepository,
+        },
+        upstream_oauth2::{
+            UpstreamOAuthLinkRepository, UpstreamOAuthProviderRepository,
+            UpstreamOAuthSessionRepository,
+        },
+        user::{
+            BrowserSessionRepository, UserEmailRepository, UserPasswordRepository, UserRepository,
+        },
+        MapErr, Repository, RepositoryTransaction,
+    };
+
+    // --- Repository ---
+    impl<R, F, E1, E2> Repository<E2> for MapErr<R, F>
+    where
+        R: Repository<E1> + RepositoryAccess<Error = E1> + RepositoryTransaction<Error = E1>,
+        F: FnMut(E1) -> E2 + Send + Sync + 'static,
+        E1: std::error::Error + Send + Sync + 'static,
+        E2: std::error::Error + Send + Sync + 'static,
+    {
+    }
+
+    // --- RepositoryTransaction --
+    impl<R, F, E> RepositoryTransaction for MapErr<R, F>
+    where
+        R: RepositoryTransaction,
+        R::Error: 'static,
+        F: FnMut(R::Error) -> E + Send + Sync + 'static,
+        E: std::error::Error,
+    {
+        type Error = E;
+
+        fn save(self: Box<Self>) -> BoxFuture<'static, Result<(), Self::Error>> {
+            Box::new(self.inner).save().map_err(self.mapper).boxed()
+        }
+
+        fn cancel(self: Box<Self>) -> BoxFuture<'static, Result<(), Self::Error>> {
+            Box::new(self.inner).cancel().map_err(self.mapper).boxed()
+        }
+    }
+
+    // --- RepositoryAccess --
+    impl<R, F, E> RepositoryAccess for MapErr<R, F>
+    where
+        R: RepositoryAccess,
+        R::Error: 'static,
+        F: FnMut(R::Error) -> E + Send + Sync + 'static,
+        E: std::error::Error + Send + Sync + 'static,
+    {
+        type Error = E;
+
+        fn upstream_oauth_link<'c>(
+            &'c mut self,
+        ) -> Box<dyn UpstreamOAuthLinkRepository<Error = Self::Error> + 'c> {
+            Box::new(MapErr::new(
+                self.inner.upstream_oauth_link(),
+                &mut self.mapper,
+            ))
+        }
+
+        fn upstream_oauth_provider<'c>(
+            &'c mut self,
+        ) -> Box<dyn UpstreamOAuthProviderRepository<Error = Self::Error> + 'c> {
+            Box::new(MapErr::new(
+                self.inner.upstream_oauth_provider(),
+                &mut self.mapper,
+            ))
+        }
+
+        fn upstream_oauth_session<'c>(
+            &'c mut self,
+        ) -> Box<dyn UpstreamOAuthSessionRepository<Error = Self::Error> + 'c> {
+            Box::new(MapErr::new(
+                self.inner.upstream_oauth_session(),
+                &mut self.mapper,
+            ))
+        }
+
+        fn user<'c>(&'c mut self) -> Box<dyn UserRepository<Error = Self::Error> + 'c> {
+            Box::new(MapErr::new(self.inner.user(), &mut self.mapper))
+        }
+
+        fn user_email<'c>(&'c mut self) -> Box<dyn UserEmailRepository<Error = Self::Error> + 'c> {
+            Box::new(MapErr::new(self.inner.user_email(), &mut self.mapper))
+        }
+
+        fn user_password<'c>(
+            &'c mut self,
+        ) -> Box<dyn UserPasswordRepository<Error = Self::Error> + 'c> {
+            Box::new(MapErr::new(self.inner.user_password(), &mut self.mapper))
+        }
+
+        fn browser_session<'c>(
+            &'c mut self,
+        ) -> Box<dyn BrowserSessionRepository<Error = Self::Error> + 'c> {
+            Box::new(MapErr::new(self.inner.browser_session(), &mut self.mapper))
+        }
+
+        fn oauth2_client<'c>(
+            &'c mut self,
+        ) -> Box<dyn OAuth2ClientRepository<Error = Self::Error> + 'c> {
+            Box::new(MapErr::new(self.inner.oauth2_client(), &mut self.mapper))
+        }
+
+        fn oauth2_authorization_grant<'c>(
+            &'c mut self,
+        ) -> Box<dyn OAuth2AuthorizationGrantRepository<Error = Self::Error> + 'c> {
+            Box::new(MapErr::new(
+                self.inner.oauth2_authorization_grant(),
+                &mut self.mapper,
+            ))
+        }
+
+        fn oauth2_session<'c>(
+            &'c mut self,
+        ) -> Box<dyn OAuth2SessionRepository<Error = Self::Error> + 'c> {
+            Box::new(MapErr::new(self.inner.oauth2_session(), &mut self.mapper))
+        }
+
+        fn oauth2_access_token<'c>(
+            &'c mut self,
+        ) -> Box<dyn OAuth2AccessTokenRepository<Error = Self::Error> + 'c> {
+            Box::new(MapErr::new(
+                self.inner.oauth2_access_token(),
+                &mut self.mapper,
+            ))
+        }
+
+        fn oauth2_refresh_token<'c>(
+            &'c mut self,
+        ) -> Box<dyn OAuth2RefreshTokenRepository<Error = Self::Error> + 'c> {
+            Box::new(MapErr::new(
+                self.inner.oauth2_refresh_token(),
+                &mut self.mapper,
+            ))
+        }
+
+        fn compat_session<'c>(
+            &'c mut self,
+        ) -> Box<dyn CompatSessionRepository<Error = Self::Error> + 'c> {
+            Box::new(MapErr::new(self.inner.compat_session(), &mut self.mapper))
+        }
+
+        fn compat_sso_login<'c>(
+            &'c mut self,
+        ) -> Box<dyn CompatSsoLoginRepository<Error = Self::Error> + 'c> {
+            Box::new(MapErr::new(self.inner.compat_sso_login(), &mut self.mapper))
+        }
+
+        fn compat_access_token<'c>(
+            &'c mut self,
+        ) -> Box<dyn CompatAccessTokenRepository<Error = Self::Error> + 'c> {
+            Box::new(MapErr::new(
+                self.inner.compat_access_token(),
+                &mut self.mapper,
+            ))
+        }
+
+        fn compat_refresh_token<'c>(
+            &'c mut self,
+        ) -> Box<dyn CompatRefreshTokenRepository<Error = Self::Error> + 'c> {
+            Box::new(MapErr::new(
+                self.inner.compat_refresh_token(),
+                &mut self.mapper,
+            ))
+        }
+    }
+
+    impl<R: RepositoryAccess + ?Sized> RepositoryAccess for Box<R> {
+        type Error = R::Error;
+
+        fn upstream_oauth_link<'c>(
+            &'c mut self,
+        ) -> Box<dyn UpstreamOAuthLinkRepository<Error = Self::Error> + 'c> {
+            (**self).upstream_oauth_link()
+        }
+
+        fn upstream_oauth_provider<'c>(
+            &'c mut self,
+        ) -> Box<dyn UpstreamOAuthProviderRepository<Error = Self::Error> + 'c> {
+            (**self).upstream_oauth_provider()
+        }
+
+        fn upstream_oauth_session<'c>(
+            &'c mut self,
+        ) -> Box<dyn UpstreamOAuthSessionRepository<Error = Self::Error> + 'c> {
+            (**self).upstream_oauth_session()
+        }
+
+        fn user<'c>(&'c mut self) -> Box<dyn UserRepository<Error = Self::Error> + 'c> {
+            (**self).user()
+        }
+
+        fn user_email<'c>(&'c mut self) -> Box<dyn UserEmailRepository<Error = Self::Error> + 'c> {
+            (**self).user_email()
+        }
+
+        fn user_password<'c>(
+            &'c mut self,
+        ) -> Box<dyn UserPasswordRepository<Error = Self::Error> + 'c> {
+            (**self).user_password()
+        }
+
+        fn browser_session<'c>(
+            &'c mut self,
+        ) -> Box<dyn BrowserSessionRepository<Error = Self::Error> + 'c> {
+            (**self).browser_session()
+        }
+
+        fn oauth2_client<'c>(
+            &'c mut self,
+        ) -> Box<dyn OAuth2ClientRepository<Error = Self::Error> + 'c> {
+            (**self).oauth2_client()
+        }
+
+        fn oauth2_authorization_grant<'c>(
+            &'c mut self,
+        ) -> Box<dyn OAuth2AuthorizationGrantRepository<Error = Self::Error> + 'c> {
+            (**self).oauth2_authorization_grant()
+        }
+
+        fn oauth2_session<'c>(
+            &'c mut self,
+        ) -> Box<dyn OAuth2SessionRepository<Error = Self::Error> + 'c> {
+            (**self).oauth2_session()
+        }
+
+        fn oauth2_access_token<'c>(
+            &'c mut self,
+        ) -> Box<dyn OAuth2AccessTokenRepository<Error = Self::Error> + 'c> {
+            (**self).oauth2_access_token()
+        }
+
+        fn oauth2_refresh_token<'c>(
+            &'c mut self,
+        ) -> Box<dyn OAuth2RefreshTokenRepository<Error = Self::Error> + 'c> {
+            (**self).oauth2_refresh_token()
+        }
+
+        fn compat_session<'c>(
+            &'c mut self,
+        ) -> Box<dyn CompatSessionRepository<Error = Self::Error> + 'c> {
+            (**self).compat_session()
+        }
+
+        fn compat_sso_login<'c>(
+            &'c mut self,
+        ) -> Box<dyn CompatSsoLoginRepository<Error = Self::Error> + 'c> {
+            (**self).compat_sso_login()
+        }
+
+        fn compat_access_token<'c>(
+            &'c mut self,
+        ) -> Box<dyn CompatAccessTokenRepository<Error = Self::Error> + 'c> {
+            (**self).compat_access_token()
+        }
+
+        fn compat_refresh_token<'c>(
+            &'c mut self,
+        ) -> Box<dyn CompatRefreshTokenRepository<Error = Self::Error> + 'c> {
+            (**self).compat_refresh_token()
+        }
     }
 }
diff --git a/crates/tasks/src/database.rs b/crates/tasks/src/database.rs
index e7947ce2..ebade53a 100644
--- a/crates/tasks/src/database.rs
+++ b/crates/tasks/src/database.rs
@@ -14,7 +14,7 @@
 
 //! Database-related tasks
 
-use mas_storage::{oauth2::OAuth2AccessTokenRepository, Repository, SystemClock};
+use mas_storage::{oauth2::OAuth2AccessTokenRepository, RepositoryAccess, SystemClock};
 use mas_storage_pg::PgRepository;
 use sqlx::{Pool, Postgres};
 use tracing::{debug, error, info};