Introduction - MapleStory Universe

The MSU Open API provides read access to MapleStory Universe data — including accounts, characters, items, game metadata, and marketplace listings. Builders can use it to create tools, dashboards, and Synergy Apps that connect with the MSU ecosystem.

Base URL: https://openapi.msu.io

1. Authentication

All requests require an API key passed as a request header.

Header	Type	Required	Value
x-nxopen-api-key	string	Yes	Your MSU Open API key

Example: x-nxopen-api-key: gw_xxxxxxxxxxxxxxxxxx

For instructions on how to obtain an API key, refer to the Getting Started with MSU Builder guide.

Keep the API key secure. Do not expose it in public repositories or client-side code.

2. Rate Limits

Rate limits are applied per API key. Higher limits are available upon request.

Level	Rate Limit (RPS)	Quota (RPD)
Default	2 RPS	3,000 RPD
Level 1	10 RPS	50,000 RPD
Level 2	30 RPS	200,000 RPD

To request a limit increase, contact the MSU Builder Team at contact_builder@nexpace.io.

RPS = Requests Per Second, RPD = Requests Per Day. Quota resets daily at 00:00 UTC.

3. Response Format

All responses use a common structure:

Success:

{

  "success": true,

  "data": { ... },

  "trace_id": "string"

}

Error (4xx / 5xx):

{

  "success": false,

  "error": { "code": 0, "message": "string" },

  "trace_id": "string"

}

MSU Resources Search Guide MSU OpenAPI Builder Guide

⌘I

​1. Authentication

​2. Rate Limits

​3. Response Format

1. Authentication

2. Rate Limits

3. Response Format