Vercel no longer supports configuration files named now.json. Builds that still use this old name will fail. Simply rename the file to vercel.json and everything will work again.

When you try to build, you’ll see a warning like this:

Warning: “now.json” is deprecated and no longer supported.

Vercel has completely dropped support for the now.json filename. You must rename it to vercel.json.

Here’s the full error message:

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Previous build caches not available.

Cloning completed: 1.240s

Warning: "now.json" is deprecated and no longer supported. Please rename it to "vercel.json". See https://vercel.com/docs/projects/project-configuration for more information.

Running "vercel build"

Vercel CLI 60.1.3

Error: The `now.json` file is deprecated and no longer supported. Please rename it to `vercel.json`.

Learn More: https://vercel.com/docs/projects/project-configuration.

Interestingly, the linked documentation doesn’t specifically mention that now.json is no longer valid — it only states that the configuration file should be named vercel.json, vercel.toml, or vercel.ts.

The fix is simple: just rename your now.json file to vercel.json. You don’t need to change any of the content inside the file.

After you push the renamed file and redeploy, the error will disappear.

File-based configuration
File-based configuration lives in your repository and gets version-controlled with your code. You can use vercel.json or vercel.toml for static configuration, or vercel.ts for programmatic configuration that runs at build time. The static formats support the same properties, while vercel.ts lets you generate configuration dynamically using environment variables, API calls, or other build-time logic. You can only use one configuration file per project.

Reprinted from: Yijile.com（ https://yijile.com/en/warning-now-json-is-deprecated-by-vercel/ ）

Licensed under CC BY-NC-SA 4.0 .
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