Case converter

Transform blocks of text between common capitalization and separator styles.

Overview

The debate over naming conventions in software development is older than most people realize — and more heated too. `camelCase` has its roots in the Smalltalk environment of the 1970s and gained mass popularity with Java in the 1990s, which adopted camelCase for variables and methods as part of its official style guide. `snake_case` is the favorite of C, Python, and Ruby: readable, unambiguous, no uppercase characters. `PascalCase` is the standard for C# and classes in general in most typed languages. `kebab-case` is impossible as an identifier in most languages (the hyphen is a subtraction operator), so it migrated to the domain of URLs, CSS slugs, and HTML attributes like `data-user-id`.

Choosing a convention is not purely aesthetic. It is a readability decision that affects the entire team maintaining the code. Usability studies on code suggest that `snake_case` may be more readable for humans because it resembles reading separate words — the visual space between words is replaced by an underscore. `camelCase` requires the brain to recognize capitalization changes as separators. `SCREAMING_SNAKE_CASE` is reserved by convention for global constants, a tradition rooted in C where `#define MAX_SIZE 100` was the standard way to declare a constant. These choices, codified in linters like ESLint and PHPStan and style guides like the Google Style Guide and PHP's PSR-12, prevent endless discussions during code review.

For developers working across multiple contexts, converting between naming formats is a daily task. A REST API returns fields in `snake_case` (Python, Rails) and the frontend expects `camelCase` (JavaScript). A database uses `SCREAMING_SNAKE_CASE` for columns and the ORM needs to map to PascalCase for classes and camelCase for properties. An i18n translation file uses `kebab-case` for keys and the TypeScript code accesses them as camelCase. Doing that mapping manually for dozens or hundreds of fields is exactly the kind of repetitive work that a tool automates well.

This tool converts full blocks of text between the most common capitalization styles: lowercase, UPPERCASE, Title Case, `camelCase`, `PascalCase`, `snake_case`, `kebab-case`, and `SCREAMING_SNAKE_CASE`. Word boundary detection works by recognizing spaces, underscores, hyphens, and transitions from uppercase to lowercase. For Unicode edge cases — proper nouns in languages with non-Latin scripts or identifiers with mixed acronyms — the result may need manual review, especially for conversions involving capitalization.

Technical deep dive

Common questions summarized

  • What is this tool for?: It runs fully in your browser: useful to validate, format, or convert data in everyday development.
  • Are my inputs sent to a server?: Processing happens locally with JavaScript. We do not store what you paste into the text areas.
  • Can I use this for real production data?: Use at your own risk. For secrets (passwords, tokens), prefer controlled environments and your company policies. And always review the generated contents. Never trust blindly things you see on the internet.

Sample payload to try

  • See also the larger "Code Snippets" sample; paste this excerpt to try locally: Input — hello world_example → HELLO WORLD_EXAMPLE (maiúsculas)

Tool guide

  • What you are working with Plain text and naming styles (variables, keys, titles).

  • What the tool does Applies styles: lower, UPPER, Title, sentence, snake_case, kebab-case, etc.

  • Why use it Rename data columns, normalise API keys, build slugs or identifiers from phrases.

Code Snippets

Code example
hello world_example → HELLO WORLD_EXAMPLE (maiúsculas)

Input

hello world_example → HELLO WORLD_EXAMPLE (maiúsculas)

FAQ

What is this tool for?

It runs fully in your browser: useful to validate, format, or convert data in everyday development.

Are my inputs sent to a server?

Processing happens locally with JavaScript. We do not store what you paste into the text areas.

Can I use this for real production data?

Use at your own risk. For secrets (passwords, tokens), prefer controlled environments and your company policies. And always review the generated contents. Never trust blindly things you see on the internet.