diff --git a/filter.test.ts b/filter.test.ts
index b7f9cea..3ca3f10 100644
--- a/filter.test.ts
+++ b/filter.test.ts
@@ -115,6 +115,16 @@ describe('Filter', () => {
       expect(result).toEqual(false)
     })
 
+    it('should return true when the timestamp of event is equal to the filter since value', () => {
+      const filter = {since: 100}
+
+      const event = buildEvent({created_at: 100})
+
+      const result = matchFilter(filter, event)
+
+      expect(result).toEqual(true)
+    })
+
     it('should return false when the event is after the filter until value', () => {
       const filter = {until: 100}
 
@@ -124,6 +134,16 @@ describe('Filter', () => {
 
       expect(result).toEqual(false)
     })
+
+    it('should return true when the timestamp of event is equal to the filter until value', () => {
+      const filter = {until: 100}
+
+      const event = buildEvent({created_at: 100})
+
+      const result = matchFilter(filter, event)
+
+      expect(result).toEqual(true)
+    })
   })
 
   describe('matchFilters', () => {
diff --git a/filter.ts b/filter.ts
index d6fe610..bd59c08 100644
--- a/filter.ts
+++ b/filter.ts
@@ -42,7 +42,7 @@ export function matchFilter(
   }
 
   if (filter.since && event.created_at < filter.since) return false
-  if (filter.until && event.created_at >= filter.until) return false
+  if (filter.until && event.created_at > filter.until) return false
 
   return true
 }