diff --git a/relay-server/src/services/buffer/envelope_buffer/mod.rs b/relay-server/src/services/buffer/envelope_buffer/mod.rs
index 8843ac3730..ad2d65e772 100644
--- a/relay-server/src/services/buffer/envelope_buffer/mod.rs
+++ b/relay-server/src/services/buffer/envelope_buffer/mod.rs
@@ -72,7 +72,10 @@ impl EnvelopesBuffer {
 #[derive(Debug)]
 struct InnerEnvelopesBuffer<S: EnvelopeStack> {
     /// The central priority queue.
-    priority_queue: priority_queue::PriorityQueue<QueueItem<StackKey, S>, Priority>,
+    priority_queue: priority_queue::PriorityQueue<
+        QueueItem<StackKey, <<S as EnvelopeStack>::Provider as StackProvider>::Stack>,
+        Priority,
+    >,
     /// A lookup table to find all stacks involving a project.
     stacks_by_project: hashbrown::HashMap<ProjectKey, BTreeSet<StackKey>>,
     stack_provider: S::Provider,
diff --git a/relay-server/src/services/buffer/envelope_stack/mod.rs b/relay-server/src/services/buffer/envelope_stack/mod.rs
index 574b5e0bd3..fb8b1114a2 100644
--- a/relay-server/src/services/buffer/envelope_stack/mod.rs
+++ b/relay-server/src/services/buffer/envelope_stack/mod.rs
@@ -6,7 +6,7 @@ pub mod memory;
 pub mod sqlite;
 
 /// A stack-like data structure that holds [`Envelope`]s.
-pub trait EnvelopeStack: Send {
+pub trait EnvelopeStack: Send + std::fmt::Debug {
     /// The error type that is returned when an error is encountered during reading or writing the
     /// [`EnvelopeStack`].
     type Error: std::fmt::Debug;
@@ -27,7 +27,7 @@ pub trait EnvelopeStack: Send {
     fn pop(&mut self) -> impl Future<Output = Result<Option<Box<Envelope>>, Self::Error>>;
 }
 
-pub trait StackProvider {
+pub trait StackProvider: std::fmt::Debug {
     type Stack: EnvelopeStack;
 
     fn create_stack(&self, envelope: Box<Envelope>) -> Self::Stack;
diff --git a/relay-server/src/services/buffer/envelope_stack/sqlite.rs b/relay-server/src/services/buffer/envelope_stack/sqlite.rs
index 894ea5f9fc..ecfd1213ad 100644
--- a/relay-server/src/services/buffer/envelope_stack/sqlite.rs
+++ b/relay-server/src/services/buffer/envelope_stack/sqlite.rs
@@ -1,18 +1,11 @@
 use std::collections::VecDeque;
-use std::error::Error;
 use std::fmt::Debug;
 use std::num::NonZeroUsize;
-use std::path::Path;
-
-use futures::StreamExt;
-use sqlx::sqlite::{SqliteConnectOptions, SqliteJournalMode, SqlitePoolOptions};
-use sqlx::{Pool, Row, Sqlite};
-use tokio::fs::DirBuilder;
 
 use relay_base_schema::project::ProjectKey;
 
 use crate::envelope::Envelope;
-use crate::services::buffer::envelope_stack::{EnvelopeStack, StackProvider};
+use crate::services::buffer::envelope_stack::EnvelopeStack;
 use crate::services::buffer::sqlite_envelope_store::SqliteEnvelopeStore;
 use crate::services::buffer::stack_provider::sqlite::SqliteStackProvider;
 
diff --git a/relay-server/src/services/buffer/sqlite_envelope_store.rs b/relay-server/src/services/buffer/sqlite_envelope_store.rs
index 62a8a6a6b8..0fe7a6c0ae 100644
--- a/relay-server/src/services/buffer/sqlite_envelope_store.rs
+++ b/relay-server/src/services/buffer/sqlite_envelope_store.rs
@@ -20,7 +20,7 @@ use crate::extractors::StartTime;
 use crate::services::buffer::envelope_stack::sqlite::SqliteEnvelopeStackError;
 use crate::Envelope;
 
-struct InsertEnvelope {
+pub struct InsertEnvelope {
     received_at: i64,
     own_key: ProjectKey,
     sampling_key: ProjectKey,