---
title: "Checks if a username is valid."
method: POST
path: "/v1/usernames/validate"
tags: ["Accounts"]
---

# Checks if a username is valid.

`POST /v1/usernames/validate`

## Request body

- RobloxAuthenticationApiModelsUsernameValidationRequest
  - `username` string
  - `birthday` string, date-time
  - `context` 0 | 1 | 2

## Response `200`

OK

- RobloxAuthenticationApiModelsUsernameValidationResponse
  - `code` 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 10 | 12 — ['ValidUsername' = 0, 'AlreadyInUseError' = 1, 'ModerationError' = 2, 'InvalidLengthError' = 3, 'StartsOrEndsWithUnderscoreError' = 4, 'TooManyUnderscoresError' = 5, 'ContainsSpacesError' = 6, 'InvalidCharactersError' = 7, 'ContainsPiiError' = 10, 'ContainsReservedUsernameError' = 12]
  - `message` string

## Other responses

- `400` — 1: A valid username is required. 2: A valid birthday or authenticated user is required.
- `403` — 0: Token Validation Failed

## Changes

- **2026-09-03** `d9b4ae8b3380` — 1 info
  - endpoint added

[Change history](https://skmtc.dev/roblox/apis/roblox-api/changes/v1/usernames/validate/post.md)

---

[API](https://skmtc.dev/roblox/apis/roblox-api.md) · [All operations](https://skmtc.dev/roblox/apis/roblox-api/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/roblox/roblox-api/revisions/d9b4ae8b3380/schema)