JamesNK/Newtonsoft.Json · error · JsonException

Path ended with open indexer.

Error message

Path ended with open indexer.

What it means

Thrown by the JPath array-indexer parser when the expression ends while still inside an open indexer, i.e. the closing ']' was never reached. The parser loop exhausts the string at JPath.cs:384-385 and throws because the indexer is unbalanced. (The same message is also used by EnsureLength checks earlier when content runs out mid-indexer.)

Source

Thrown at Src/Newtonsoft.Json/Linq/JsonPath/JPath.cs:385

                    start = _currentIndex;
                    end = null;
                }
                else if (!char.IsDigit(currentCharacter) && currentCharacter != '-')
                {
                    throw new JsonException("Unexpected character while parsing path indexer: " + currentCharacter);
                }
                else
                {
                    if (end != null)
                    {
                        throw new JsonException("Unexpected character while parsing path indexer: " + currentCharacter);
                    }

                    _currentIndex++;
                }
            }

            throw new JsonException("Path ended with open indexer.");
        }

        private void EatWhitespace()
        {
            while (_currentIndex < _expression.Length)
            {
                if (_expression[_currentIndex] != ' ')
                {
                    break;
                }

                _currentIndex++;
            }
        }

        private PathFilter ParseQuery(char indexerCloseChar, bool scan)
        {
            _currentIndex++;

View on GitHub (pinned to 4f73e74372)

Solutions

1. Add the missing closing ']' to balance the indexer, e.g. $[1].
2. When building paths dynamically, ensure every '[' has a matching ']'.
3. Validate bracket balance before passing the path to SelectToken.

Example fix

// before
token.SelectToken("$.data[1");

// after
token.SelectToken("$.data[1]");

// Verify bracket balance before querying
static bool BracketsBalanced(string path)
{
    int depth = 0;
    foreach (char c in path)
    {
        if (c == '[') depth++;
        else if (c == ']') depth--;
        if (depth < 0) return false;
    }
    return depth == 0;
}

try
{
    token.SelectToken(path);
}
catch (JsonException ex) when (ex.Message.Contains("Path ended with open indexer"))
{
    path += "]"; // attempt to close the indexer
}

When it happens

Trigger: A path like token.SelectToken("$[1") or "$[" where the opening '[' has no matching ']'. The parser enters ParseArrayIndexer and runs off the end of the string.

Common situations: Truncating a path string; building a path with string concatenation that omits the closing bracket; a formatting bug that drops trailing characters.

Related errors

• Unexpected character while parsing path:
• Unexpected character following indexer:
• Unexpected end while parsing path.
• Array index expected.
• Unexpected character while parsing path indexer:

AI-assisted analysis of JamesNK/Newtonsoft.Json@4f73e74372 (2026-08-07). Data as JSON: /api/errors/c3aa646c4423cba9. Report an issue: GitHub.