remotion-dev/remotion · error · Error

The custom Layer ARN ${layerArn} is in region ${match[2]}, b

Error message

The custom Layer ARN ${layerArn} is in region ${match[2]}, but the function is being deployed to ${region}.

What it means

validateCustomLayerArns compares the region segment of each layer ARN (regex group 2) with the region passed to deployFunction. Lambda layers are regional resources: a layer published in us-east-1 is invisible to a function in eu-west-1, so Remotion rejects the mismatch up front instead of letting the AWS API fail later.

Source

Thrown at packages/lambda/src/shared/validate-custom-layer-arns.ts:70

				'Each customLayerArns entry must be a non-empty string.',
			);
		}

		const match = layerArn.match(layerVersionArnRegex);
		if (!match) {
			throw new TypeError(
				`Invalid Lambda Layer version ARN: ${layerArn}. Expected arn:<partition>:lambda:<region>:<12-digit-account-id>:layer:<layer-name>:<numeric-version>.`,
			);
		}

		if (match[1] !== partition) {
			throw new Error(
				`The custom Layer ARN ${layerArn} uses partition ${match[1]}, but region ${region} uses partition ${partition}.`,
			);
		}

		if (match[2] !== region) {
			throw new Error(
				`The custom Layer ARN ${layerArn} is in region ${match[2]}, but the function is being deployed to ${region}.`,
			);
		}

		if (seen.has(layerArn)) {
			throw new Error(`Duplicate custom Layer ARN: ${layerArn}.`);
		}

		seen.add(layerArn);
	}
};

View on GitHub (pinned to 10db9de073)

Solutions

Publish the layer in the target region (`aws lambda publish-layer-version --region <target>`) and use that ARN.
Build the layer list per region, e.g. a map `{[region]: layerArn}` instead of a single constant.

Example fix

// before
const layerArn = 'arn:aws:lambda:us-east-1:123456789012:layer:libs:1';
await deployFunction({region: 'eu-west-1', customLayerArns: [layerArn]});

// after: per-region map
const layerArnsByRegion = {
  'us-east-1': 'arn:aws:lambda:us-east-1:123456789012:layer:libs:1',
  'eu-west-1': 'arn:aws:lambda:eu-west-1:123456789012:layer:libs:1',
};
await deployFunction({region: 'eu-west-1', customLayerArns: [layerArnsByRegion['eu-west-1']]});

Defensive patterns

Strategy: validation

Validate before calling

const bad = customLayerArns.filter((a) => !a.includes(`:lambda:${region}:`));
if (bad.length > 0) {
  throw new Error(`Layer ARNs not in ${region}: ${bad.join(', ')}`);
}

Type guard

const isLayerArnInRegion = (arn: string, region: string): boolean =>
  new RegExp(`:lambda:${region}:\d{12}:layer:`).test(arn);

Prevention

Publish layers programmatically per region and store ARNs in a region-keyed map.
Never reuse a hardcoded layer ARN constant across multi-region deploys.

When it happens

Trigger: Calling deployFunction({region: 'eu-west-1', customLayerArns: ['arn:aws:lambda:us-east-1:...:layer:x:1']}) — any combination where the ARN region differs from the deploy region.

Common situations: Changing the deploy region in config but forgetting to republish/update the layer ARNs; copying layer ARNs from a colleague working in another region; multi-region deploy scripts sharing one layer list.

Related errors

AI-assisted analysis of remotion-dev/remotion@10db9de073 (2026-08-22). Data as JSON: /api/errors/f1154f60a17c0950. Report an issue: GitHub.