Snake Case & Camel Case Converter

When writing APIs, developers often need to convert backend fields like batch_export_time into frontend camelCase formats like batchExportTime. Manually changing a bunch of fields is tedious and prone to errors. Simply open our converter, paste your text, select the conversion direction, and get instant results. Let's take a detailed look at how to use it and what pitfalls to avoid.

When to Use This Tool

Field Name Conversion for Frontend-Backend Integration
Backend APIs typically return JSON fields separated by underscores (snake_case), such as user_id or created_at. Frontend JavaScript/TypeScript developers prefer using camelCase, like userId or createdAt. Manually renaming dozens of fields every time is slow and error-prone.
With our tool, you just need to copy the entire JSON snippet or list of fields into the input box, select "Snake Case to Camel Case", and the camelCase version will instantly appear in the right-hand result area, ready to be replaced.

Converting Database Column Names to Entity Properties
Database column names often use underscores, such as order_status, while Java entity classes follow the camelCase convention like orderStatus. When creating new entities with a DDL script, simply paste it here to generate all property names with one click, saving you from refactoring them one by one in your IDE.

Standardizing Configuration Files or Environment Variables
Some configuration files use database_url, others use all-caps with underscores like DATABASE_URL, and some use databaseUrl. You can paste the underscore version here, select "Snake Case to Camel Case", and quickly unify your team's naming style with just a little manual case adjustment.

What Are Snake Case and Camel Case?

Snake case (underscore naming) connects all-lowercase words with underscores (_), such as user_name or last_login_time. It originated from C language traditions and is highly prevalent in Python, Ruby, and database schemas.

Camel case starts with a lowercase first word, and the first letter of each subsequent word is capitalized, all joined together, such as userName or lastLoginTime. The standard libraries and frameworks of languages like Java, JavaScript, and Swift almost exclusively use camelCase. PascalCase (upper camel case) also capitalizes the very first letter and is commonly used for class names.

Our tool handles the conversion between lower camelCase and snake_case, covering the vast majority of API and variable usage scenarios.

How to Use This Converter

At the top of the page, you will see two main areas: the input area on the left and the result area on the right, with a conversion direction toggle button in the middle.

Step 1: Paste the strings you want to convert into the large "Input Text" box on the left. This can be one word per line, multiple lines, or even text containing numbers and special characters.

Step 2: Confirm the conversion direction. There are two options above the text box: "Snake Case to Camel Case" and "Camel Case to Snake Case". Click the corresponding option based on your original format; the selected option will be highlighted.

Step 3: Click the blue "Convert" button. The converter will process each line according to the selected direction and instantly output the converted text in the right-hand result area.

Step 4: Check the results on the right. If a line does not match the target format (for example, no underscores are found when converting snake case to camel case), the result will remain unchanged, and a prompt below will indicate the skipped lines. You can also click the "Copy" icon in the top right corner of the result area to copy all results with one click.

Batch Processing Tip: Directly paste an entire JSON snippet or a multi-line list of variable names. The converter processes each line independently, preserving blank lines and whitespace so your formatting remains intact.

Complete Example: Step-by-Step Conversion

Let's demonstrate with a real user API JSON snippet.

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