remotion-dev/remotion · error · Error

The `content` must not be empty

Error message

The `content` must not be empty

What it means

After confirming the artifact `content` is a string, Remotion rejects strings that are empty or contain only whitespace (`content.trim() === ''`). This prevents writing zero-byte artifact files during a render. The check is in `validateContent`, reached for non-thumbnail artifacts.

Solutions

1. Provide non-whitespace content for the artifact.
2. If the artifact is optional, conditionally skip registering it when content is empty.
3. Compute and check `content.trim()` before assigning.

Example fix

// before
const content = maybeText ?? '';
registerArtifact({type:'artifact', filename:'note.txt', contentType:'text', content});
// after
const content = maybeText ?? '';
if (content.trim() !== '') {
  registerArtifact({type:'artifact', filename:'note.txt', contentType:'text', content});
}

if (typeof content === 'string' && content.trim() === '') {
  throw new Error('content string must not be empty/whitespace');
}

When it happens

Trigger: A non-thumbnail artifact is registered with `content` equal to `''`, `' '`, a whitespace-only template literal, or a string that is only newlines/tabs.

Common situations: A template literal that interpolates an undefined variable yielding empty text; reading an empty file into a string; defaulting content to an empty string as a placeholder.

Related errors

• The "content" must be a string or Uint8Array, but you…
• No effects were specified for deletion
• No effects were specified for duplication
• A custom role ARN must either be "undefined" or a string…
• A "duration" of a spring is NaN, which it must not be

AI-assisted analysis of remotion-dev/remotion@78fe4bb3fd (2026-08-12). Data as JSON: /api/errors/6060aedece413992. Report an issue: GitHub.

Appendix: source

Thrown at packages/core/src/validation/validate-artifact.ts:29

		throw new Error('The `filename` must not be empty');
	}

	if (!filename.match(/^([0-9a-zA-Z-!_.*'()/:&$@=;+,?]+)/g)) {
		throw new Error(
			'The `filename` must match "/^([0-9a-zA-Z-!_.*\'()/:&$@=;+,?]+)/g". Use forward slashes only, even on Windows.',
		);
	}
};

const validateContent = (content: unknown) => {
	if (typeof content !== 'string' && !(content instanceof Uint8Array)) {
		throw new TypeError(
			`The "content" must be a string or Uint8Array, but you passed a value of type ${typeof content}`,
		);
	}

	if (typeof content === 'string' && content.trim() === '') {
		throw new Error('The `content` must not be empty');
	}
};

export const validateRenderAsset = (artifact: TRenderAsset) => {
	// We don't have validation for it yet
	if (artifact.type !== 'artifact') {
		return;
	}

	validateArtifactFilename(artifact.filename);

	if (artifact.contentType === 'thumbnail') {
		return;
	}

	validateContent(artifact.content);
};

View on GitHub (pinned to 78fe4bb3fd)