---
title: "Preview Field Rules"
method: POST
path: "/api/v1/ontology/entities/{entity_id}/properties/preview-rules"
tags: ["ontology-entities"]
---

# Preview Field Rules

`POST /api/v1/ontology/entities/{entity_id}/properties/preview-rules`

Count existing rows that would violate the candidate field rules (no data is changed).

## Path parameters

- `entity_id` string, uuid, required

## Request body

- RulesPreviewRequest
  - `properties` RulesPreviewItem[], required
    - `column_name` string, required
    - `rules` FieldRules, required — Declared value rules for one entity field. Empty instance = no rules.
      - `allowed_values` string[], nullable
      - `required` boolean
      - `format` FieldFormat — Type-specific value constraints. All optional; only set what applies.
        - `min` number, nullable
        - `max` number, nullable
        - `regex` string, nullable
        - `max_length` integer, nullable
        - `date_min` string, nullable
        - `date_max` string, nullable
        - `allowed_mime` string[], nullable
        - `max_size_bytes` integer, nullable

## Response `200`

Successful Response

- RulesPreviewResponse
  - `results` RulesPreviewResult[], required
    - `column_name` string, required
    - `violating_count` integer, required
    - `total_count` integer, required

## Other responses

- `422` — Validation Error

---

[API](https://skmtc.dev/netter/apis/dmi-backend.md) · [All operations](https://skmtc.dev/netter/apis/dmi-backend/llms.txt) · [OpenAPI document](https://skmtc.dev/netter/apis/dmi-backend/revisions/77d4fd215b57?raw)