sveltejs/kit · error

Invalid route ${id} — parameters must be separated

Error message

Invalid route ${id} — parameters must be separated

What it means

Route ID validation error: after unescaping [x+..]/[u+..] sequences, the walker detected adjacent parameter brackets like [a][b] in a single segment. Dynamic parameters in one route segment must be separated by static text (e.g. [lang]-[slug]), because the framework cannot infer the separator. Fires during manifest generation when such a route file/directory exists.

Source

Thrown at packages/kit/src/core/sync/create_manifest_data/index.js:167

				if (type === 'x') {
					if (code.length !== 2) {
						throw new Error(`Hexadecimal escape sequence in ${id} must be two characters`);
					}

					return String.fromCharCode(parseInt(code, 16));
				} else {
					if (code.length < 4 || code.length > 6) {
						throw new Error(
							`Unicode escape sequence in ${id} must be between four and six characters`
						);
					}

					return String.fromCodePoint(parseInt(code, 16));
				}
			});

			if (/\]\[/.test(unescaped)) {
				throw new Error(`Invalid route ${id} — parameters must be separated`);
			}

			if (count_occurrences('[', id) !== count_occurrences(']', id)) {
				throw new Error(`Invalid route ${id} — brackets are unbalanced`);
			}

			if (/#/.test(segment)) {
				// Vite will barf on files with # in them
				throw new Error(`Route ${id} should be renamed to ${id.replace(/#/g, '[x+23]')}`);
			}

			if (/\[\.\.\.[\w-]+\]\/\[\[/.test(id)) {
				throw new Error(
					`Invalid route ${id} — an [[optional]] route segment cannot follow a [...rest] route segment`
				);
			}

			if (/\[\[\.\.\./.test(id)) {

View on GitHub (pinned to 03f1687fe6)

Solutions

1. Insert static text between the parameters, e.g. rename [lang][slug] to [lang]-[slug]
2. Split the parameters across nested directories so each segment has one parameter

When it happens

Trigger: Thrown at packages/kit/src/core/sync/create_manifest_data/index.js:167 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of sveltejs/kit@03f1687fe6 (2026-09-02). Data as JSON: /api/errors/32ad5df4986ba946. Report an issue: GitHub.