Log Level

Controlling the verbosity of logs during the bundling process helps you focus on what matters most. The recommended way to manage log output in tsdown is by using the --log-level option.

Usage

To suppress all logs—including errors—set the log level to silent:

tsdown --log-level silent

To display only error messages, set the log level to error:

tsdown --log-level error

This is useful for CI/CD pipelines or scenarios where you want minimal or no console output.

Available Log Levels

• silent: No logs are shown, including errors.
• error: Only error messages are shown.
• warn: Warnings and errors are logged.
• info: Informational messages, warnings, and errors are logged (default).

Choose the log level that best fits your workflow to control the amount of information displayed during the build process.

Fail on Warnings

The failOnWarn option controls whether warnings cause the build to exit with a non-zero code.

tsdown.config.ts

import { defineConfig } from 'tsdown'

export default defineConfig({
  // Always fail on warnings
  failOnWarn: true,
  // Fail on warnings only in CI
  failOnWarn: 'ci-only',
})

See CI Environment for more about CI-aware options.

Suppressing Warnings

Some warnings are purely informational and not actionable in your project. The suppressWarnings option lets you silence warnings whose message matches a given pattern.

tsdown.config.ts

import { defineConfig } from 'tsdown'

export default defineConfig({
  suppressWarnings: [
    // Substring match
    'is experimental',
    // RegExp match
    /Circular dependency/,
  ],
  // Or a predicate function
  // suppressWarnings: (msg) => msg.includes('is experimental'),
})

suppressWarnings accepts a string (substring match), a RegExp, an array of either, or a (msg: string) => boolean predicate.

Matched warnings are dropped before failOnWarn is applied, so a suppressed warning will not fail the build even when failOnWarn is enabled. This is useful for opting out of non-actionable notices (such as the TypeScript 7.0 experimental API warning) while keeping failOnWarn: true for everything else.