diff --git a/src/activitypub/queues.rs b/src/activitypub/queues.rs
index 539d1f1..0585093 100644
--- a/src/activitypub/queues.rs
+++ b/src/activitypub/queues.rs
@@ -29,7 +29,7 @@ use super::receiver::{handle_activity, HandlerError};
 pub struct IncomingActivityJobData {
     activity: Value,
     is_authenticated: bool,
-    failure_count: i32,
+    failure_count: u32,
 }
 
 impl IncomingActivityJobData {
@@ -44,11 +44,11 @@ impl IncomingActivityJobData {
     pub async fn into_job(
         self,
         db_client: &impl DatabaseClient,
-        delay: i64,
+        delay: u32,
     ) -> Result<(), DatabaseError> {
         let job_data = serde_json::to_value(self)
             .expect("activity should be serializable");
-        let scheduled_for = Utc::now() + Duration::seconds(delay);
+        let scheduled_for = Utc::now() + Duration::seconds(delay.into());
         enqueue_job(
             db_client,
             &JobType::IncomingActivity,
@@ -58,18 +58,22 @@ impl IncomingActivityJobData {
     }
 }
 
+const INCOMING_QUEUE_BATCH_SIZE: u32 = 10;
+const INCOMING_QUEUE_RETRIES_MAX: u32 = 2;
+
+const fn incoming_queue_backoff(_failure_count: u32) -> u32 {
+    // Constant, 10 minutes
+    60 * 10
+}
+
 pub async fn process_queued_incoming_activities(
     config: &Config,
     db_client: &mut impl DatabaseClient,
 ) -> Result<(), DatabaseError> {
-    let batch_size = 10;
-    let max_retries = 2;
-    let retry_after = 60 * 10; // 10 minutes
-
     let batch = get_job_batch(
         db_client,
         &JobType::IncomingActivity,
-        batch_size,
+        INCOMING_QUEUE_BATCH_SIZE,
     ).await?;
     for job in batch {
         let mut job_data: IncomingActivityJobData =
@@ -88,12 +92,13 @@ pub async fn process_queued_incoming_activities(
                 job_data.failure_count,
                 job_data.activity,
             );
-            if job_data.failure_count <= max_retries &&
+            if job_data.failure_count <= INCOMING_QUEUE_RETRIES_MAX &&
                 // Don't retry after fetcher recursion error
                 !matches!(error, HandlerError::FetchError(FetchError::RecursionError))
             {
                 // Re-queue
                 log::info!("activity re-queued");
+                let retry_after = incoming_queue_backoff(job_data.failure_count);
                 job_data.into_job(db_client, retry_after).await?;
             };
         };
@@ -126,16 +131,17 @@ impl OutgoingActivityJobData {
     }
 }
 
+const OUTGOING_QUEUE_BATCH_SIZE: u32 = 1;
+
 pub async fn process_queued_outgoing_activities(
     config: &Config,
     db_pool: &DbPool,
 ) -> Result<(), DatabaseError> {
     let db_client = &**get_database_client(db_pool).await?;
-    let batch_size = 1;
     let batch = get_job_batch(
         db_client,
         &JobType::OutgoingActivity,
-        batch_size,
+        OUTGOING_QUEUE_BATCH_SIZE,
     ).await?;
     for job in batch {
         let job_data: OutgoingActivityJobData =
diff --git a/src/models/background_jobs/queries.rs b/src/models/background_jobs/queries.rs
index 63ebe7f..e26ad02 100644
--- a/src/models/background_jobs/queries.rs
+++ b/src/models/background_jobs/queries.rs
@@ -30,7 +30,7 @@ pub async fn enqueue_job(
 pub async fn get_job_batch(
     db_client: &impl DatabaseClient,
     job_type: &JobType,
-    batch_size: i64,
+    batch_size: u32,
 ) -> Result<Vec<DbBackgroundJob>, DatabaseError> {
     let rows = db_client.query(
         "
@@ -54,7 +54,7 @@ pub async fn get_job_batch(
             &JobStatus::Running,
             &job_type,
             &JobStatus::Queued,
-            &batch_size,
+            &i64::from(batch_size),
         ],
     ).await?;
     let jobs = rows.iter()