> ## Documentation Index
> Fetch the complete documentation index at: https://docs.cradl.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Validators

> Automatically validate fields.

Validators let you define rules that check whether extracted fields meet your requirements — so you only review documents that actually need attention. This helps you reduce manual work and improve data quality at scale.

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### Available Validators

Here’s a quick overview of the validators you can use to automatically flag documents for review:

* **Confidence threshold**\
  Triggers a review if the model’s confidence in a field is below a specified percentage. Useful for catching uncertain predictions.
* **Logical expression**\
  Validates a field using custom logic (e.g. `total_amount > 0`). Ideal for numeric checks, date comparisons, and other business rules.
* **RegEx**\
  Ensures that a field matches a specific pattern using regular expressions. Great for validating formats like postal codes, VAT numbers, or phone numbers.
* **Cannot be empty**\
  Flags the document if a required field is missing or empty. Use this to make sure essential information is always extracted.