diff --git a/src/core/strings/str8/str8.c b/src/core/strings/str8/str8.c
index b204e36..8340228 100644
--- a/src/core/strings/str8/str8.c
+++ b/src/core/strings/str8/str8.c
@@ -1,5 +1,6 @@
 #include "str8.h"
 #include "aliases.h"
+#include <string.h>
 
 c8 wapp_str8_get(const Str8 *str, u64 index) {
   if (index >= str->size) {
@@ -16,3 +17,33 @@ void wapp_str8_set(Str8 *str, u64 index, c8 c) {
 
   str->buf[index] = c;
 }
+
+i64 wapp_str8_find(Str8RO *str, Str8RO substr) {
+  if (substr.size > str->size) {
+    return -1;
+  }
+
+  for (u64 i = 0; i < str->size; ++i) {
+    const c8 *sub = str->buf + i;
+    if (memcmp(sub, substr.buf, substr.size) == 0) {
+      return i;
+    }
+  }
+
+  return -1;
+}
+
+i64 wapp_str8_rfind(Str8RO *str, Str8RO substr) {
+  if (substr.size > str->size) {
+    return -1;
+  }
+
+  for (i64 i = str->size - substr.size; i >= 0; --i) {
+    const c8 *sub = str->buf + i;
+    if (memcmp(sub, substr.buf, substr.size) == 0) {
+      return i;
+    }
+  }
+
+  return -1;
+}
diff --git a/src/core/strings/str8/str8.h b/src/core/strings/str8/str8.h
index 8557db0..7e6f98f 100644
--- a/src/core/strings/str8/str8.h
+++ b/src/core/strings/str8/str8.h
@@ -35,6 +35,9 @@ typedef const Str8 Str8RO;
 c8   wapp_str8_get(Str8RO *str, u64 index);
 void wapp_str8_set(Str8 *str, u64 index, c8 c);
 
+i64 wapp_str8_find(Str8RO *str, Str8RO substr);
+i64 wapp_str8_rfind(Str8RO *str, Str8RO substr);
+
 #ifdef __cplusplus
 END_C_LINKAGE
 #endif // !__cplusplus