diff --git a/src/string_func.h b/src/string_func.h
index c7c9478dcb..00f1d3fcfd 100644
--- a/src/string_func.h
+++ b/src/string_func.h
@@ -76,7 +76,9 @@ inline size_t ttd_strnlen(const char *str, size_t maxlen)
 bool IsValidChar(char32_t key, CharSetFilter afilter);
 
 size_t Utf8Decode(char32_t *c, const char *s);
-inline size_t Utf8Decode(char32_t *c, std::string::iterator &s) { return Utf8Decode(c, &*s); }
+/* std::string_view::iterator might be char *, in which case we do not want this templated variant to be taken. */
+template <typename T> requires (!std::is_same_v<T, char *> && (std::is_same_v<std::string_view::iterator, T> || std::is_same_v<std::string::iterator, T>))
+inline size_t Utf8Decode(char32_t *c, T &s) { return Utf8Decode(c, &*s); }
 size_t Utf8Encode(char *buf, char32_t c);
 size_t Utf8Encode(std::ostreambuf_iterator<char> &buf, char32_t c);
 size_t Utf8Encode(std::back_insert_iterator<std::string> &buf, char32_t c);
diff --git a/src/stringfilter.cpp b/src/stringfilter.cpp
index 16800c2440..9ec17a7267 100644
--- a/src/stringfilter.cpp
+++ b/src/stringfilter.cpp
@@ -25,34 +25,34 @@ static const char32_t STATE_QUOTE2 = '"';
  * Set the term to filter on.
  * @param str Filter term
  */
-void StringFilter::SetFilterTerm(const char *str)
+void StringFilter::SetFilterTerm(std::string_view str)
 {
 	this->word_index.clear();
 	this->word_index.shrink_to_fit();
 	this->word_matches = 0;
-	free(this->filter_buffer);
-
-	assert(str != nullptr);
-
-	char *dest = MallocT<char>(strlen(str) + 1);
-	this->filter_buffer = dest;
 
 	char32_t state = STATE_WHITESPACE;
-	const char *pos = str;
-	WordState *word = nullptr;
-	size_t len;
-	for (;; pos += len) {
+	auto pos = str.begin();
+	auto word_begin = str.end();
+	auto word_end = pos;
+
+	/* Helper to prevent duplicating code. */
+	auto add_word = [&] () {
+		if (word_begin != str.end()) {
+			this->word_index.emplace_back(std::string(word_begin, word_end + 1), false);
+			word_begin = str.end();
+		}
+	};
+
+	for (size_t len; pos < str.end(); pos += len) {
 		char32_t c;
 		len = Utf8Decode(&c, pos);
 
-		if (c == 0 || (state == STATE_WORD && IsWhitespace(c))) {
+		if (state == STATE_WORD && IsWhitespace(c)) {
 			/* Finish word */
-			if (word != nullptr) {
-				*(dest++) = '\0';
-				word = nullptr;
-			}
+			add_word();
 			state = STATE_WHITESPACE;
-			if (c != 0) continue; else break;
+			continue;
 		}
 
 		if (state == STATE_WHITESPACE) {
@@ -74,22 +74,14 @@ void StringFilter::SetFilterTerm(const char *str)
 		}
 
 		/* Add to word */
-		if (word == nullptr) {
-			word = &this->word_index.emplace_back(WordState{ dest, false });
+		if (word_begin == str.end()) {
+			word_begin = pos;
 		}
-
-		memcpy(dest, pos, len);
-		dest += len;
+		word_end = pos;
 	}
-}
 
-/**
- * Set the term to filter on.
- * @param str Filter term
- */
-void StringFilter::SetFilterTerm(const std::string &str)
-{
-	this->SetFilterTerm(str.c_str());
+	/* Add the last word of the string. */
+	add_word();
 }
 
 /**
@@ -119,12 +111,12 @@ void StringFilter::AddLine(const char *str)
 	for (WordState &ws : this->word_index) {
 		if (!ws.match) {
 			if (this->locale_aware) {
-				if (match_case ? StrNaturalContains(str, ws.start) : StrNaturalContainsIgnoreCase(str, ws.start)) {
+				if (match_case ? StrNaturalContains(str, ws.word) : StrNaturalContainsIgnoreCase(str, ws.word)) {
 					ws.match = true;
 					this->word_matches++;
 				}
 			} else {
-				if ((match_case ? strstr(str, ws.start) : strcasestr(str, ws.start)) != nullptr) {
+				if ((match_case ? strstr(str, ws.word.c_str()) : strcasestr(str, ws.word.c_str())) != nullptr) {
 					ws.match = true;
 					this->word_matches++;
 				}
diff --git a/src/stringfilter_type.h b/src/stringfilter_type.h
index ec7d545fd8..14283addd2 100644
--- a/src/stringfilter_type.h
+++ b/src/stringfilter_type.h
@@ -31,13 +31,12 @@ struct StringFilter {
 private:
 	/** State of a single filter word */
 	struct WordState {
-		const char *start;                         ///< Word to filter for.
+		std::string word;                          ///< Word to filter for.
 		bool match;                                ///< Already matched?
 	};
 
-	const char *filter_buffer;                     ///< Parsed filter string. Words separated by 0.
 	std::vector<WordState> word_index;             ///< Word index and filter state.
-	uint word_matches;                             ///< Summary of filter state: Number of words matched.
+	uint word_matches = 0;                         ///< Summary of filter state: Number of words matched.
 
 	const bool *case_sensitive;                    ///< Match case-sensitively (usually a static variable).
 	bool locale_aware;                             ///< Match words using the current locale.
@@ -47,11 +46,9 @@ public:
 	 * Constructor for filter.
 	 * @param case_sensitive Pointer to a (usually static) variable controlling the case-sensitivity. nullptr means always case-insensitive.
 	 */
-	StringFilter(const bool *case_sensitive = nullptr, bool locale_aware = true) : filter_buffer(nullptr), word_matches(0), case_sensitive(case_sensitive), locale_aware(locale_aware) {}
-	~StringFilter() { free(this->filter_buffer); }
+	StringFilter(const bool *case_sensitive = nullptr, bool locale_aware = true) : case_sensitive(case_sensitive), locale_aware(locale_aware) {}
 
-	void SetFilterTerm(const char *str);
-	void SetFilterTerm(const std::string &str);
+	void SetFilterTerm(std::string_view str);
 
 	/**
 	 * Check whether any filter words were entered.