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1. What is MSU Builder?

MSU Builder (msu.io/builder) is the official platform where Builders can register, manage accounts, and access the tools and resources needed to build within the MapleStory Universe ecosystem. Using the MSU Open API and other resources available through the Builder Center, Builders can create services, tools, and content that connect with MSU’s games, assets, and community. The onboarding process follows these steps:
  • Step 1. Create a Builder account
  • Step 2. Enter your app name to get a test API Key instantly.
  • Step 3. Build and test with your API Key. When you’re ready, apply for live review to increase your API call limit and go live.
　

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2. Creating a Builder Account

Visit https://msu.io/builder and click the ‘Connect’ button to begin the sign-up process.
Connecting through other MSU services will register a Mapler account, not a Builder account. To sign up as a Builder, make sure to connect through the Builder Center.

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2.1. Wallet Connection

계정가입1 Builders can sign up using a MetaMask wallet or a social account (Google, X, or Apple). For detailed instructions on wallet creation and sign-up methods, refer to [Wallet Connect Guide].
Wallets already registered as a Mapler or Builder account cannot be used to sign up. Please use a new wallet that has not been registered with MSU.

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2.2. Fill in Information and Email Verification

1 become a builder Enter the following: nickname, email address. Review and agree to the terms, then proceed with sign-up.
Email addresses already verified under another MSU Builder account cannot be used. If a duplicate email error appears, the email is already associated with another Builder account. Please use a different email address to sign up.
2 메일 인증 A 5-digit verification code will be sent to the registered email address. Enter the code in the ‘Verification Code’ field and click ‘Confirm.’
  • The code is valid for 5 minutes. If it expires, click ‘Resend’ to receive a new code.
  • If the email is not received, check the Spam or Deleted folders and make sure the email address was entered correctly.

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2.3. Signature Request

3 서명 A signature request will appear in the wallet. Review the request details — Wallet Address, Network (Henesys), and the requesting site (MapleStory Universe) — then click ‘Confirm’ to sign.
Only sign this message if the request is from MapleStory Universe (http://msu.io). This request does not trigger a blockchain transaction or incur any gas fees.

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2.4. Asset Access Permission

4 Asset Access Permission An ‘Asset Access Permission’ popup will appear. This grants MSU services permission to access the following assets in the wallet: • Characters, NFT Items, FT Items, Nicknames, NESO Allowing access enables the following services:
  • MSU Marketplace: Item, character, and nickname trading
  • Reactor: Item Fusion
  • Swap & Warp: NESO-NXPC swap and warp-out
The following services are not available with Builder access:
  • MapleStory N: Normal play including item enhancement and minting
Click ‘Proceed’ to grant access.

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2.5. Final Signature Request

5 Signature Request A signature request for asset access permissions will appear. Review the message and click ‘Confirm’ to complete the sign-up.

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2.6. Account Created — Level 0

Builder Get Started 2 6 Once a Builder account is created, Maplers can use key MSU services (MSU Marketplace, Swap & Warp) and register synergy apps to get test API Keys. Up to 5 synergy apps can be registered per account. 　

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3. KYC/KYB Verification

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3.1. Complete KYC Verification

Builder Get Started 3 1 You can complete the verification process through My Page > Verification in the Builder Center.

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3.2. Verification Complete

Once KYC/KYB verification is approved, My Page will update to show ‘Complete ✓’. The following features will be activated:
For details on features available at each KYC/KYB level, refer to [Builder Verification].
　

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4. Receiving the API Key

Builder Get Started 4 Once you create a synergy app by entering its name, a test API Key is issued instantly. You can check the issued key under the ‘API Key’ menu on the app detail page. The test API Key is granted full access to general API scopes and has an expiration date. You can extend it starting 30 days before expiration.
Keep the API key secure. Do not share it publicly or commit it to public code repositories.
　

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5. Checking Builder and Verification Level

The current Builder level and KYC/KYB verification status can be checked at any time on the My Page in the Builder Center. • Visit http://msu.io/builder and log in • Navigate to My Page to view the current verification level and feature access status
For questions or issues, contact the MSU Builder Team at contact_builder@nexpace.io or visit the Builder Forum at forum.msu.io.
　

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6. Live Synergy App Review

Builder Get Started 6 Your synergy app can go live once it passes review. Submit your app for live review using the ‘Submit for Review’ button at the top right of the app detail page. Once approved, your API Key’s call limit is increased and the app switches to Live status. Apps in Live status can issue OAuth Credentials.