What this error means

MIDDLEWARE_INVOCATION_FAILED: Cannot find module @swc/helpers/esm/_interop_require_default.js is a Next.js / Vercel failure pattern reported for developers trying to fix vercel middleware_invocation_failed cannot find module @swc/helpers. Based on the imported evidence, treat this as a tool-specific troubleshooting page rather than a generic API error.

Why this happens

Next.js 16.2.6 + proxy.ts middleware + @sentry/nextjs import triggers MIDDLEWARE_INVOCATION_FAILED. @swc/helpers/esm/_interop_require_default.js not found at runtime. Multiple duplicate reports. Closed as duplicate but root cause unresolved.

Common causes

  • Deploying Next.js 16.2.x with proxy.ts middleware and Sentry import breaks Vercel deployment. Common stack (Next.js + Sentry) makes this widespread. Build succeeds locally but fails on Vercel.
  • Next.js 16.2.6 + proxy.ts middleware + @sentry/nextjs import triggers MIDDLEWARE_INVOCATION_FAILED. @swc/helpers/esm/_interop_require_default.js not found at runtime. Multiple duplicate reports. Closed as duplicate but root cause unresolved.

Quick fixes

  1. Confirm the exact error signature matches MIDDLEWARE_INVOCATION_FAILED: Cannot find module @swc/helpers/esm/_interop_require_default.js.
  2. Check the Next.js / Vercel account, local tool state, and provider configuration involved in the failing workflow.
  3. Check the build output, project root, and deployment platform configuration before redeploying.

Platform/tool-specific checks

  • Verify the command, editor, extension, or API client that produced the error.
  • Compare local settings with CI, deployment, or editor-level settings when the error appears in only one environment.
  • Avoid deleting credentials, local model data, or project settings until the failing scope is clear.

Step-by-step troubleshooting

  1. Capture the exact error message and the command, editor action, or request that triggered it.
  2. Check whether the failure is account/auth, quota/rate, model/provider, local runtime, or deployment configuration.
  3. Review the source evidence below and compare it with your environment.
  4. Apply one change at a time and rerun the smallest failing action.
  5. Keep the working fix documented for the team or deployment environment.

How to prevent it

  • Keep provider/tool configuration documented.
  • Record non-secret diagnostics such as tool version, provider name, model name, and command path.
  • Add a lightweight check before CI or production workflows depend on the tool.