# Experimental build mode for Hono and Express projects

By Steven Van · 2026-01-15

An opt-in flag for Hono and Express projects adds per-route log filtering and fixes module resolution in the build pipeline.

An experimental build mode for [Vercel](<https://creatorstoolbox.com/tools/vercel>) projects using Hono or Express adds per-route log filtering, similar to what Next.js projects already get.

The mode also changes how the build pipeline resolves modules:

- Relative imports no longer require file extensions

- TypeScript path aliases are supported

- ESM and CommonJS interoperability is improved

It is off by default. To turn it on, set VERCEL\_EXPERIMENTAL\_BACKENDS=1 in the [project's environment variables](<https://vercel.com/changelog/experimental-build-mode-hono-express>).

![Vercel](<https://www.google.com/s2/favicons?domain=vercel.com&sz=128>)

Vercel

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[Original source](<https://vercel.com/docs/frameworks/backend/hono>)

[Read Experimental build mode for Hono and Express projects on Creators Toolbox](<https://creatorstoolbox.com/blog/vercel-experimental-build-mode-for-hono-and-express-projects>)

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Canonical source: https://creatorstoolbox.com/blog/vercel-experimental-build-mode-for-hono-and-express-projects