diff --git a/src/string.c b/src/string.c
index 7d29603..afeec59 100644
--- a/src/string.c
+++ b/src/string.c
@@ -16,6 +16,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+#include <stddef.h>
 #include <string.h>
 #include "string.h"
 
@@ -50,3 +51,25 @@ char* strnstr(const char* haystack, const char* needle, size_t s)
 
     return NULL;
 }
+
+char* strrepl(char* source, char* find, char* repl)
+{
+    size_t repl_len = strlen(repl);
+    char* result = NULL;
+    char* n;
+    char* needle = source;
+
+    do
+    {
+        n = strstr(find);
+        if (!n) break;
+        result = realloc(result, n - source + repl_len + 1);
+        result[n - source + repl_len] = '\0';
+        // Copy initial string up to here
+        strncpy(result, find, n - source - 1);
+        
+    } while (n);
+
+    // Return source string if no replacements
+    return result ? result : source;
+}
diff --git a/src/string.h b/src/string.h
index 4b7de8a..87993f3 100644
--- a/src/string.h
+++ b/src/string.h
@@ -23,5 +23,6 @@
 int streql(char* cmp1, char* cmp2);
 int strneql(char* cmp1, char* cmp2, size_t cmp1_n);
 char* strnstr(const char* haystack, const char* needle, size_t s);
+char* strrepl(char* source, char* find, char* replace);
 
 #endif // TREE_STRING_H
diff --git a/test/unit/main.c b/test/unit/main.c
index 4349159..ace6823 100644
--- a/test/unit/main.c
+++ b/test/unit/main.c
@@ -22,11 +22,12 @@
 
 // Imports
 #include "mime_multipart.c"
-
+#include "string_test.c"
 int main()
 {
     struct test tests[] = {
-        { "Mime multipart parser", mime_multipart_test }
+        { "Mime multipart parser", mime_multipart_test },
+        { "Strings", string_replace_test }
     };
     return iterate_tests(tests, sizeof(tests)/sizeof(tests[0]));
 }
diff --git a/test/unit/string_test.c b/test/unit/string_test.c
new file mode 100644
index 0000000..2f570ec
--- /dev/null
+++ b/test/unit/string_test.c
@@ -0,0 +1,6 @@
+
+int string_replace_test(void)
+{
+    strrepl
+    return 0;
+}