Reserved Usernames
Learn which usernames are reserved by platforms, why they're restricted, and how to check them programmatically. No need to maintain manual lists.
What are Reserved Usernames?
Reserved usernames are identifiers that platforms restrict from public registration. These include system terms, brand names, celebrity names, geographic locations, and premium short handles. Platforms reserve these usernames to prevent impersonation, protect intellectual property, maintain security, and support monetization.
Understanding which usernames are reserved helps you build better registration flows, prevent user confusion, and comply with platform policies.
Examples by Category
System & Infrastructure
Technical usernames like admin, root, and api that platforms block to prevent conflicts with core functionality and administrative access.
Brand Names & Trademarks
Trademarked company names and brand identifiers that platforms protect to prevent impersonation and trademark infringement.
Celebrities & Public Figures
Names of famous individuals, influencers, politicians, and public personalities that require identity verification.
Geographic Locations
City names, country names, states, and notable locations that platforms often reserve for official regional accounts.
Government & Official Entities
Government agencies, law enforcement, regulatory bodies, and official institutional identifiers.
Security & Authentication
Security-related terms like login, password, and verify that could be exploited for phishing and credential theft.
Why Hardcoded Lists Break at Scale
Maintaining a hardcoded list of reserved usernames creates several problems:
- Lists become outdated as new brands emerge and platforms evolve
- Different platforms have different reservation policies
- Category coverage is incomplete (you miss edge cases)
- Manual updates are time-consuming and error-prone
- No metadata about why a username is reserved
Instead, use the username.dev API to check usernames programmatically. The API stays current with platform policies and provides category metadata for each check.
Test This with Your Own Username
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Programmatic Enforcement
Integrate username checks into your registration flow with a simple API call: