String Formatter
Convert text to camelCase, snake_case, PascalCase, kebab-case, or CONSTANT_CASE instantly. Free and private — runs entirely in your browser.
String Formatter & Case Converter
Instantly convert text between camelCase, snake_case, PascalCase, and more.
lowercase
All characters to lower case
UPPERCASE
All characters to UPPER CASE
Title Case
Capitalize Every Word
Sentence case.
Capitalize first word of sentences
camelCase
programmingVariableStyle
PascalCase
ProgrammingClassStyle
snake_case
python_variable_style
kebab-case
url-routing-style
CONSTANT_CASE
ENVIRONMENT_VARIABLE_STYLE
iNVERT cASE
Swaps UPPER and lower case
What is a String Formatter?
A string formatter is a developer utility that converts text between programming naming conventions — camelCase, snake_case, PascalCase, kebab-case, CONSTANT_CASE, and more. Instead of retyping variable names by hand, you paste your text and the tool transforms it into every standard format simultaneously using Regular Expressions.
Different programming languages enforce different naming standards for variables, functions, classes, and constants. This tool eliminates the manual work of translating between them when working across codebases, cleaning CSV imports, or preparing text for a CMS.
How to Use the String Formatter
Paste your text
Type or paste the text you want to convert — a variable name, column header, sentence, or multi-line list all work.
View all conversions instantly
All 10 output formats update in real time as you type — no button to press.
Copy the format you need
Click the copy icon next to the output format you want. Paste directly into your code editor, database migration, or CMS field.
Use bulk text options
For multi-line input, use the extra options to sort lines, remove duplicates, trim whitespace, or reverse text before converting.
Programming Case Conventions Explained
Understanding when and where to use specific naming conventions is crucial for writing clean, maintainable, and syntactically correct code. Here are the most common cases and their standard use cases:
Standard for: JavaScript, TypeScript, Java, C#, and C++ Variables.
The first letter is lowercase, and the first letter of each subsequent concatenated word is capitalized. No spaces or underscores are used.
Standard for: Python, Ruby, Rust, and Database Column Names.
All letters are lowercase, and spaces are replaced with an underscore _.
Standard for: Class Names, React Components, and Interfaces.
Similar to camelCase, but the very first letter is also capitalized.
Standard for: URLs, HTML/CSS class names, and Git branch names.
All letters are lowercase, and spaces are replaced with a hyphen -.
Standard for: Global constants and Environment Variables (.env).
All letters are capitalized, and spaces are replaced with an underscore _.
Who Is This For?
- ▸ Developers working across languages or frameworks who need to translate variable names from Python snake_case to JavaScript camelCase, or from a database column to a React prop.
- ▸ Data engineers cleaning column headers from a CSV export — converting "First Name", "Last Name", "Account Balance" into snake_case before loading into a database table.
- ▸ Content teams normalizing text before importing into a CMS who need page slugs in kebab-case or field IDs in camelCase without manually editing every entry.
Key Benefits
- ✓ Runs entirely in your browser — your text never leaves your device, making it safe for proprietary code and API keys.
- ✓ Free forever — no subscription, no paywall, no usage limits.
- ✓ No account required — open the page and start converting immediately.
- ✓ 10 formats simultaneously — all outputs update in real time as you type, so you can grab any format without re-running anything.
Common String Formatting Mistakes
- Case-converting strings with locale-dependent characters: The Turkish letter "i" uppercases to "İ" (with a dot), not "I". JavaScript's
toUpperCase()is locale-aware in some environments — always test with non-ASCII input if your users are international. - Not preserving intentional casing in acronyms: Converting "parseHTML" to snake_case naively produces
parse_h_t_m_linstead ofparse_html. Always verify that multi-character acronyms survive your case conversion correctly. - Breaking camelCase by splitting on wrong boundaries: A string like "myAPIResponse" can be split as "my-API-Response" or "my-A-P-I-Response" depending on the algorithm. Check output when input contains consecutive uppercase letters.
For validating that converted strings match expected patterns, use the JSON formatter when the strings are JSON keys. For building patterns to match specific case formats, the regex tester lets you validate your naming patterns against real examples.
Further reading: MDN — String Reference (Mozilla Developer Network)
Common Use Cases
You are integrating a Python API into a JavaScript frontend. The API returns snake_case field names — first_name, account_balance — but your React component expects camelCase props. Paste the field list and copy the camelCase output in seconds.
You exported a CSV from a spreadsheet and the column headers are in "Title Case with spaces." You need them in snake_case before running a database migration. Paste all headers at once and copy the transformed list.
You are building a new React component library and need consistent PascalCase component names and kebab-case file names for each entry. Convert a list of component descriptions into both formats simultaneously.
You received a list of marketing terms from a brief and need them normalized to kebab-case for use as URL slugs across 20 landing pages. Paste the list, copy the kebab-case output, done.
Frequently Asked Questions
What is a string formatter?
A string formatter is a developer utility that converts text between programming naming conventions — camelCase, snake_case, PascalCase, kebab-case, and CONSTANT_CASE. It parses your input and transforms it into multiple programming-standard formats simultaneously, saving time when working across languages or cleaning imported data.
Is this tool free?
Yes — completely free with no account required. The string formatter runs entirely in your browser. Your text is never sent to a server, making it safe for proprietary code, API keys, and sensitive content.
What is the difference between camelCase and PascalCase?
camelCase starts with a lowercase letter: myVariableName. PascalCase starts with an uppercase letter: MyVariableName. PascalCase is the standard for class names and React components. camelCase is standard for variables and functions in JavaScript, TypeScript, and Java.
What is snake_case used for?
snake_case uses all lowercase letters with underscores between words: my_variable_name. It is the standard for Python variable names, database column names, and file names on Linux systems. It is also common in REST API response keys from Python or Ruby backends.
What is kebab-case?
kebab-case uses all lowercase letters with hyphens between words: my-variable-name. It is used in CSS class names, HTML attributes, URL slugs, and file names in web projects. Git branch names and npm package names also commonly use kebab-case.
Why is my text getting stripped of punctuation?
Programming naming conventions like camelCase and PascalCase do not allow special characters such as !, @, #, or commas inside a variable name. The formatter sanitizes input and removes invalid punctuation to produce compiler-ready output. Underscores and hyphens are preserved in the formats that use them.
The calculators on The Simple Toolbox are for educational and planning purposes only. Results are estimates based on your inputs and standard assumptions — they are not financial, legal, or tax advice. Consult a qualified professional before making significant financial decisions.
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