Unity-Technologies/UnityCsReference · error · JSONParseException

missing '"' to end string at {}

Error message

missing '"' to end string at {}

What it means

ParseString scans for the next '"' or '\' via IndexOfAny; if neither is found before end of input, it throws JSONParseException ("missing '"' to end string at <pos>"). This is the unterminated-string signal: the opening quote was seen but no closing quote (and no escape) followed within the buffer.

Source

Thrown at Editor/Mono/AssetStore/Json.cs:524

                }
            }
            Next();
            return new JSONValue(dict);
        }

        static readonly char[] endcodes = { '\\', '"' };

        private JSONValue ParseString()
        {
            string res = "";

            Next();

            while (idx < len)
            {
                int endidx = json.IndexOfAny(endcodes, idx);
                if (endidx < 0)
                    throw new JSONParseException("missing '\"' to end string at " + PosMsg());

                res += json.Substring(idx, endidx - idx);

                if (json[endidx] == '"')
                {
                    cur = json[endidx];
                    idx = endidx;
                    break;
                }

                endidx++; // get escape code
                if (endidx >= len)
                    throw new JSONParseException("End of json while parsing while parsing string at " + PosMsg());

                // char at endidx is \
                char ncur = json[endidx];
                switch (ncur)
                {

View on GitHub (pinned to 225b0fbdb5)

Solutions

1. Verify the input is complete (read to EOF / match Content-Length) before parsing.
2. Ensure all string literals are properly terminated and quotes inside are escaped (\").
3. Catch JSONParseException and report the position for repair.

Example fix

// before
// { "msg": "hello world }

// after
// { "msg": "hello world" }

if (string.IsNullOrEmpty(json)) throw new InvalidOperationException("empty JSON");
// For unterminated strings, verify completeness by reading to EOF before parsing.

try { v = JSON.Parse(json); }
catch (JSONParseException ex) { /* position locates the unterminated string */ throw; }

When it happens

Trigger: Truncated input cut mid-string; a literal string containing an unescaped quote that confused the structure; missing closing quote in hand-written JSON.

Common situations: Network truncation; copy/paste that dropped the trailing quote; embedding user text without escaping.

Related errors

• End of json while parsing while parsing string at {}
• End of json while parsing while parsing unicode char near {}
• End of json while parsing at {}
• Cannot parse json value starting with '{}' at {}
• Key not string type at {}

AI-assisted analysis of Unity-Technologies/UnityCsReference@225b0fbdb5 (2026-08-13). Data as JSON: /api/errors/73fbae36c8df502c. Report an issue: GitHub.