anomalyco/sst · error · VisibleError

No deployment regions specified. Please specify at least one

Error message

No deployment regions specified. Please specify at least one region in the 'regions' property.

What it means

SSR site components support regional deployment via the `regions` prop (or the fallback of the current stack's region). If the resulting regions list is empty — e.g. `regions: []` — SST refuses to deploy because at least one deployment region is required to create the server functions.

Source

Thrown at platform/src/components/aws/ssr-site.ts:1224

        if (!sitePath) return ".";

        if (!fs.existsSync(sitePath)) {
          throw new VisibleError(
            `Site directory not found at "${path.resolve(
              sitePath,
            )}". Please check the path setting in your configuration.`,
          );
        }
        return sitePath;
      });
    }

    function normalizeRegions() {
      return output(
        args.regions ?? [getRegionOutput(undefined, { parent: self }).region],
      ).apply((regions) => {
        if (regions.length === 0)
          throw new VisibleError(
            "No deployment regions specified. Please specify at least one region in the 'regions' property.",
          );

        return regions.map((region) => {
          if (
            [
              "ap-south-2",
              "ap-southeast-4",
              "ap-southeast-5",
              "ca-west-1",
              "eu-south-2",
              "eu-central-2",
              "il-central-1",
              "me-central-1",
            ].includes(region)
          )
            throw new VisibleError(
              `Region ${region} is not supported by this component. Please select a different AWS region.`,

View on GitHub (pinned to a0bd20f762)

Solutions

Provide at least one region, e.g. `regions: ["us-east-1"]`
Remove the `regions` prop entirely to default to the stack's own region
Fix the logic/env var feeding the regions array so it is non-empty

Example fix

// before
new sst.aws.NextjsSite("Web", { path: "src", regions: [] });
// after
new sst.aws.NextjsSite("Web", { path: "src", regions: ["us-east-1"] });

Defensive patterns

Strategy: validation

Validate before calling

const regions = process.env.SITE_REGIONS?.split(",") ?? [];
if (regions.length === 0) {
  throw new Error("Provide at least one region via SITE_REGIONS or omit `regions` to use the stack region");
}

Type guard

function hasRegions(r: string[] | undefined): r is [string, ...string[]] {
  return Array.isArray(r) && r.length > 0;
}

Try / catch

try {
  new sst.aws.NextjsSite("Web", { path: "src", regions });
} catch (e) {
  if (String(e).includes("No deployment regions")) console.error("regions resolved to empty list");
  throw e;
}

Prevention

Don't pass `regions: []`; omit the prop to default to the stack's region
Validate any env-driven regions list before constructing the component
Type regions as [string, ...string[]] to catch empties at compile time

When it happens

Trigger: Explicitly passing `regions: []` to an SSR site component, or providing a regions array that resolves to an empty list.

Common situations: Dynamically computing regions from env/config that ends up empty; copy-pasting an example with a placeholder list and clearing it; conditional logic that strips all regions in some environments.

Understand the failure class

Background: "X is required", "must be set", "cannot be empty": the missing-required-config error family, from Vertex AI project/location to WeChat keys — this error's family across 18 libraries.

Related errors

AI-assisted analysis of anomalyco/sst@a0bd20f762 (2026-08-30). Data as JSON: /api/errors/7bc03be0ddc7de02. Report an issue: GitHub.