diff --git a/packages/parser/lib/css_lexer.rei b/packages/parser/lib/css_lexer.rei
new file mode 100644
index 000000000..7c0f54b20
--- /dev/null
+++ b/packages/parser/lib/css_lexer.rei
@@ -0,0 +1,28 @@
+module Types = Css_types;
+module Parser = Css_parser;
+module Location = Ppxlib.Location;
+
+/** Signals a lexing error at the provided source location. */
+exception LexingError((Lexing.position, Lexing.position, string));
+
+/** Makes the lexer be aware of whitespaces or not */
+let skip_whitespace: ref(bool);
+
+type token_with_location = {
+  txt: result(Tokens.token, (Tokens.token, Tokens.error)),
+  loc: Types.loc,
+};
+
+let get_next_token: Sedlexing.lexbuf => Parser.token;
+let get_next_tokens_with_location:
+  Sedlexing.lexbuf => (Parser.token, Lexing.position, Lexing.position);
+let from_string: string => result(list(token_with_location), [> | `Frozen]);
+let tokenize:
+  string =>
+  result(list((Parser.token, Lexing.position, Lexing.position)), string);
+let render_token: Parser.token => string;
+let position_to_string: Lexing.position => string;
+let debug_token: ((Parser.token, Lexing.position, Lexing.position)) => string;
+let to_string: list((Parser.token, 'a, 'b)) => string;
+let to_debug:
+  list((Parser.token, Lexing.position, Lexing.position)) => string;