anomalyco/sst · error · VisibleError

Base path configuration not found in ".next/routes-manifest.

Error message

Base path configuration not found in ".next/routes-manifest.json" for site "${name}". Check your Next.js configuration.

What it means

SST's Nextjs component reads the built app's .next/routes-manifest.json to discover the basePath configured in next.config.js so it can wire up routing/CloudFront correctly. If the file can't be parsed or lacks a usable basePath, it assumes the build output is corrupt or produced by a misconfigured Next.js build and throws this VisibleError.

Source

Thrown at platform/src/components/aws/nextjs.ts:836

            throw new VisibleError(
              `Build ID not found in ".next/BUILD_ID" for site "${name}". Ensure your Next.js app was built successfully.`,
            );
          }
        }

        function loadBasePath() {
          try {
            const content = fs.readFileSync(
              path.join(outputPath, ".next", "routes-manifest.json"),
              "utf-8",
            );
            const json = JSON.parse(content) as {
              basePath: string;
            };
            return json.basePath === "" ? undefined : json.basePath;
          } catch (e) {
            console.error(e);
            throw new VisibleError(
              `Base path configuration not found in ".next/routes-manifest.json" for site "${name}". Check your Next.js configuration.`,
            );
          }
        }

        function loadPrerenderManifest() {
          try {
            const content = fs
              .readFileSync(
                path.join(outputPath, ".next/prerender-manifest.json"),
              )
              .toString();
            return JSON.parse(content) as {
              version: number;
              routes: Record<string, unknown>;
            };
          } catch (e) {
            console.debug("Failed to load prerender-manifest.json", e);

View on GitHub (pinned to a0bd20f762)

Solutions

1. Run `next build` (or `sst build`) so a fresh .next/routes-manifest.json exists before deploying
2. Delete the .next directory and rebuild to rule out a corrupt manifest
3. Verify the `path` pointing to the Next.js app in the SST component config is the app root that contains .next
4. Check next.config.js basePath is a string (empty string is allowed) and the Next.js version is supported by SST

Example fix

// before
new sst.aws.Nextjs("Web", { path: "packages/web" }); // deployed without building
// after
// package.json: "deploy": "next build && sst deploy"
new sst.aws.Nextjs("Web", { path: "packages/web" });

import { existsSync, readFileSync } from "fs";
const manifest = ".next/routes-manifest.json";
if (!existsSync(manifest)) throw new Error("Run `next build` before deploying: routes-manifest.json missing");
const parsed = JSON.parse(readFileSync(manifest, "utf8"));
if (typeof parsed.basePath !== "string") throw new Error("routes-manifest.json is missing a valid basePath");

function hasValidRoutesManifest(m: unknown): m is { basePath: string } {
  return typeof m === "object" && m !== null && typeof (m as any).basePath === "string";
}

try {
  const manifest = JSON.parse(readFileSync(".next/routes-manifest.json", "utf8"));
} catch {
  throw new Error(".next build output invalid — run `next build` first");
}

When it happens

Trigger: Running `sst deploy`/`sst dev` for a Nextjs site where .next/routes-manifest.json is missing, malformed JSON, or JSON.parse throws — e.g. the site was never built (`next build` not run), build artifacts were cleaned, or an incompatible Next.js version produced an unexpected manifest format.

Common situations: Deploying before building the app in CI, a stale or partially-cleaned .next directory, monorepo path misconfiguration pointing at the wrong build output, or upgrading Next.js to a version whose routes-manifest.json no longer matches the expected shape.

Related errors

• Could not load OpenNext output file at "${openNextOutputPath
• Build ID not found in ".next/BUILD_ID" for site "${name}". E
• TanStack Start server bundle not found at: "${serverPath}"
• Build metadata file not found at "${filePath}". Update your
• Lambda@Edge runtime is deprecated. Update your OpenNext conf

AI-assisted analysis of anomalyco/sst@a0bd20f762 (2026-08-30). Data as JSON: /api/errors/34a95ecbbfdbdd1e. Report an issue: GitHub.