# Code Smell 283 - Unresolved Meta Tags > TL;DR: Incomplete or null meta tags break functionality and user experience. # Problems - Tags appear in output - Email texts include placeholders between human-readable text - Missed placeholders confuse users - Websites are rendered with strange characters - [Null](https://maximilianocontieri.com/null-the-billion-dollar-mistake) values trigger errors - Potential [security injection vulnerabilities](https://maximilianocontieri.com/code-smell-189-not-sanitized-input) # Solutions 1. Validate meta tags 2. Assert completeness early 3. [Fail Fast](https://maximilianocontieri.com/fail-fast) 4. Avoid [null](https://maximilianocontieri.com/refactoring-015-remove-null) values 5. Throw meaningful exceptions 6. Automate meta validation # Context When you leave meta tags unfinished, such as `{user_name}` or `{product_name}`, they often sneak into your final output. Imagine sending an email that says, "Hi {user_name}, your order for {product_name} is ready." It screams unprofessionalism and confuses users. [Null](https://maximilianocontieri.com/code-smell-12-null) values worsen things by causing crashes or silent failures, leading to bad user experiences or broken processes. You can avoid this by asserting completeness before rendering or sending. When your code finds an incomplete meta tag or a null value, stop the process immediately and throw an exception. # Sample Code ## Wrong ```php ```php The best error message is the one that never shows up. _Thomas Fuchs_ %[https://maximilianocontieri.com/software-engineering-great-quotes] * * * This article is part of the CodeSmell Series. %[https://maximilianocontieri.com/how-to-find-the-stinky-parts-of-your-code]