How to bulk delete 20,000 documents of a specific type in Sanity?

For bulk deleting 20,000 documents of a particular type in Sanity, here's the most efficient approach:

The Challenge

You're hitting two main limitations:

1. 10,000 document limit per delete query - When using delete by query, you can only operate on up to 10,000 documents at a time
2. Rate limits - 25 mutations/second per IP and max 100 concurrent mutations per dataset

Recommended Solution: Use the CLI Migration Tool

The Sanity CLI migration tool is specifically designed for this scenario and handles batching/rate limiting automatically:

npx sanity@latest migration create deleteUsers

Then create a migration script:

import {defineMigration, at, unset} from 'sanity/migrate'

export default defineMigration({
  title: 'Delete all users',
  documentTypes: ['users'],
  
  // This will delete all documents of type 'users'
  filter: '_type == "users"',
  
  migrate: {
    document() {
      // Return null to delete the document
      return null
    }
  }
})

Run with:

npx sanity migration run deleteUsers

Benefits:

• Automatically batches mutations to avoid rate limits
• Built-in dry-run mode by default
• Shows progress and handles errors gracefully
• Can handle all 20,000 documents without manual pagination

Alternative: Paginated Delete Script

If you need more control, paginate by _id to work within the 10,000 document limit:

import {getCliClient} from 'sanity/cli'

const client = getCliClient()

async function deleteInBatches() {
  let lastId = ''
  let hasMore = true
  
  while (hasMore) {
    // Query max 10,000 docs at a time
    const query = lastId 
      ? `*[_type == "users" && _id > $lastId][0...10000]._id`
      : `*[_type == "users"][0...10000]._id`
    
    const ids = await client.fetch(query, {lastId})
    
    if (ids.length === 0) {
      hasMore = false
      break
    }
    
    // Delete in transaction
    const transaction = ids.reduce(
      (tx, id) => tx.delete(id),
      client.transaction()
    )
    
    await transaction.commit()
    
    lastId = ids[ids.length - 1]
    console.log(`Deleted ${ids.length} documents. Last ID: ${lastId}`)
    
    // Optional: add delay to respect rate limits
    await new Promise(resolve => setTimeout(resolve, 1000))
  }
}

deleteInBatches()

Key Points

• The 10,000 document limit applies to delete-by-query operations specifically
• The migration tool is the recommended modern approach and handles all the complexity
• For manual scripts, paginate by _id (not array slicing) for better performance
• With 20,000 documents and rate limits, expect the full deletion to take a few minutes

The migration tool is definitely your best bet here - it's built exactly for this type of bulk operation and will handle the 20,000 documents efficiently without you having to worry about rate limits or batching logic.