#shard

• Type: { count: number; index: number }
• Default: undefined
• CLI: --shard <index>/<count>

Shards test files for parallel execution. count represents the total number of shards, and index represents the index of the current shard (1-based).

This option can only be set at the root level of your configuration, not within individual projects.

This is particularly useful for parallelizing tests in CI/CD environments, allowing you to split the test suite into multiple parts and run them independently across different jobs, thereby reducing overall test time.

# Split tests into 3 shards, run the 1st shard
npx rstest --shard 1/3

import { defineConfig } from '@rstest/core';

export default defineConfig({
  shard: {
    count: 3,
    index: 1,
  },
});