---
title: "ReasonCode"
url: "https://dev.ionova.ai/apis/ars-address-resolution-service-4/versions/fdd2c316-7f84-4f04-8bb7-64e9bf97893b/schemas/ReasonCode"
---

> Full API specification: https://dev.ionova.ai/apis/ars-address-resolution-service-4/versions/fdd2c316-7f84-4f04-8bb7-64e9bf97893b.md

# ReasonCode

Structured reason code. Prefix indicates category: FMT = format, FLD = field, REG = regulatory, ENT = entity, VRF = verification, CNV = conversion.

## OpenAPI definition

```yaml
openapi: 3.0.3
info:
  title: ARS — Address Resolution Service
  version: 4.3.1
servers:
  - url: https://api-uat.ionova.ai/ars
    description: UAT (test data only)
components:
  schemas:
    ReasonCode:
      type: object
      xml:
        name: ReasonCode
      description: >
        Structured reason code. Prefix indicates category:

        FMT = format, FLD = field, REG = regulatory, ENT = entity, VRF =
        verification, CNV = conversion.
      required:
        - code
        - severity
        - message
      properties:
        code:
          type: string
          description: Reason code in PREFIX-NN format (e.g. FMT-01, REG-05, VRF-03).
          example: REG-05
        severity:
          type: string
          enum:
            - ERROR
            - WARNING
            - INFO
          description: Severity level.
        field:
          type: string
          description: ISO 20022 field name the reason applies to (e.g. TownName,
            AddressLine).
        message:
          type: string
          description: Human-readable explanation.
        ruleSource:
          type: string
          description: Regulatory reference (e.g. EPC SCT Rulebook §3.4, CBPR+ MP §2.1).
```