diff --git a/src/fuzz.cpp b/src/fuzz.cpp
index eacc770..a3b6657 100644
--- a/src/fuzz.cpp
+++ b/src/fuzz.cpp
@@ -16,7 +16,7 @@ std::pair<std::string, WeaselJsonStatus> runStreaming(std::string copy,
       return {state.result, s};
     }
   } else {
-    for (int i = 0; i < copy.size(); i += stride) {
+    for (size_t i = 0; i < copy.size(); i += stride) {
       auto s = WeaselJsonParser_parse(parser.get(), copy.data() + i,
                                       std::min<int>(stride, copy.size() - i));
       if (s != WeaselJson_AGAIN) {
diff --git a/src/json_value.h b/src/json_value.h
index c71dfa6..8cb4782 100644
--- a/src/json_value.h
+++ b/src/json_value.h
@@ -202,7 +202,7 @@ inline std::optional<JsonValue> toValue(std::string copy, int stride) {
       return std::nullopt;
     }
   } else {
-    for (int i = 0; i < copy.size(); i += stride) {
+    for (size_t i = 0; i < copy.size(); i += stride) {
       if (WeaselJsonParser_parse(parser.get(), copy.data() + i,
                                  std::min<int>(stride, copy.size() - i)) !=
           WeaselJson_AGAIN) {