What causes "Invalid JSON: failed to parse" in n8n-io/n8n?

Invalid JSON: failed to parse

Error message

Invalid JSON: failed to parse

What it means

Error "Invalid JSON: failed to parse" thrown in n8n-io/n8n.

Source

Thrown at packages/@n8n/instance-ai/src/parsers/structured-file-parser.ts:321

	// Check for dangerous keys in CSV/TSV headers (consistent with JSON validation)
	for (const header of rawHeaders) {
		if (DANGEROUS_KEYS.has(header.trim())) {
			throw new Error(`Dangerous column header "${header.trim()}" found in ${format} data`);
		}
	}

	return { rawHeaders, allRows: dataRows };
}

function parseJson(content: string): {
	rawHeaders: string[];
	allRows: Array<Record<string, unknown>>;
} {
	let parsed: unknown;
	try {
		parsed = JSON.parse(content);
	} catch {
		throw new Error('Invalid JSON: failed to parse');
	}

	if (!Array.isArray(parsed)) {
		throw new Error('Expected a JSON array of objects, got a single value or object');
	}

	if (parsed.length === 0) {
		return { rawHeaders: [], allRows: [] };
	}

	// Collect all keys across all objects (preserving order of first appearance)
	const keySet = new Set<string>();
	for (const item of parsed) {
		if (typeof item !== 'object' || item === null || Array.isArray(item)) {
			throw new Error('JSON array items must be flat objects (not arrays, nulls, or primitives)');
		}
		const dangerousKey = hasDangerousKey(item as Record<string, unknown>);
		if (dangerousKey) {

View on GitHub (pinned to 5ac6606e81)

When it happens

Trigger: Thrown at packages/@n8n/instance-ai/src/parsers/structured-file-parser.ts:321 when the library encounters an invalid state.

Common situations: See trigger scenarios.

Understand the failure class

Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

AI-assisted analysis of n8n-io/n8n@5ac6606e81 (2026-08-12). Data as JSON: /api/errors/1b13802e68ba71ff. Report an issue: GitHub.