Convert Between camelCase, snake_case, PascalCase and More

The Six Common Case Formats

Identifier naming conventions vary significantly across programming languages, frameworks, and domains. The converter handles all of the commonly used formats:

• camelCase — first word lowercase, subsequent words capitalised, no separators. Standard for variables and function names in JavaScript, Java, Swift, and Kotlin.
• PascalCase — every word capitalised, no separators. Used for class names, type names, and constructor functions across most languages.
• snake_case — all lowercase, words separated by underscores. The default convention in Python, Ruby, and SQL.
• SCREAMING_SNAKE_CASE — all uppercase, underscores between words. Used for constants and environment variables across virtually all languages.
• kebab-case — all lowercase, words separated by hyphens. Standard for CSS class names, HTML attributes, URL slugs, and CLI flags.
• dot.case — words separated by dots. Used in configuration files, property keys (Java properties, some YAML schemas), and logging namespaces.
• Title Case — each word capitalised with spaces, used in headings, labels, and display names rather than code.

When Each Convention Applies

camelCase in JavaScript and TypeScript

JavaScript uses camelCase for variables, function names, and object properties. TypeScript follows the same conventions with additional PascalCase for interfaces, types, and classes. When you name a REST API field in a Node.js backend, it's typically camelCase (userId, createdAt). The same field serialised to JSON and consumed by a Python client would ideally be converted to user_id and created_at — and that translation is exactly what this tool helps with.

snake_case in Python and SQL

Python's style guide (PEP 8) specifies snake_case for function names, variable names, and module names. Database column names follow the same convention in most SQL dialects. When integrating a Python backend with a JavaScript frontend, the case mismatch between the two layers is a constant source of manual conversion work.

PascalCase for Types and Classes

Class names are PascalCase in essentially every major language: Python, JavaScript, Java, C#, Go (exported identifiers), Swift, Kotlin, and Rust. When you're generating code or creating types from an OpenAPI schema or database schema, converting field names to PascalCase for the class name is a near-universal requirement.

kebab-case in CSS and URLs

CSS class names and HTML custom attributes use kebab-case (font-size, data-user-id). URL paths follow the same pattern (/user-profile, /blog/my-article-title). Kebab-case is also the standard for npm package names and CLI command flags (--dry-run, --output-format).

Handling Common Pitfalls

Acronyms Like URL, HTML, and ID

Acronyms in identifiers are handled differently across conventions. In camelCase, "URL" at the start becomes url, mid-word it becomes Url in some codebases and URL in others. In PascalCase, you'll see both ParseUrl and ParseURL in production code. The converter follows a consistent rule: acronyms are treated as word units, so parseURL input splits into ["parse", "URL"] and converts predictably. If your team has a specific acronym convention, use the output as a starting point and adjust the acronym capitalisation manually.

Numbers in Identifiers

Numbers create word boundary ambiguity. Is base64Encode two words ("base64" and "encode") or three ("base", "64", "encode")? The converter treats a number sequence adjacent to letters as part of the preceding word, so base64Encode becomes base64_encode in snake_case rather than base_64_encode. Verify the output when numbers are involved.

Mixed-Case Input

The converter accepts any of these formats as input — you don't need to clean your identifier first. Paste my-variable-name, MY_VARIABLE_NAME, myVariableName, or even My Variable Name and the tool will detect the word boundaries and generate all formats from there.

Practical Batch Conversion Workflow

When renaming variables across a codebase, the most efficient approach is to generate all case variants upfront, then use your editor's find-and-replace or a code mod to apply the changes. Use the converter to get the snake_case, camelCase, and kebab-case versions of the new name simultaneously, then run three targeted replacements — one per format.

This is particularly useful when refactoring across API boundaries: the database uses snake_case, the JavaScript frontend uses camelCase, and the URL routes use kebab-case. All three need updating together. Generating all variants at once means you don't have to mentally derive each format under pressure.