# Convert snake_case to camelCase

> Convert snake_case identifiers to camelCase online. Free converter for renaming API fields and variables, with a live bulk tool.

Consuming a Python or Ruby API from JavaScript usually means mapping snake_case fields to camelCase properties. This converter splits identifiers on underscores, lowercases the first word, and capitalizes the rest — the standard camelCase convention in JavaScript, Java, and Swift.

## Example: snake_case → camelCase

Input:
```
user_name
created_at
http_server_error
is_active
```

Output:
```
userName
createdAt
httpServerError
isActive
```

## How to convert snake_case to camelCase

1. Split the identifier on each underscore (user_name → user, name).
2. Lowercase the first word and capitalize the first letter of every following word.
3. Join the words back together with no separator.

## FAQ

### What is the difference between camelCase and PascalCase?

camelCase starts with a lowercase letter (userName); PascalCase capitalizes the first word too (UserName). JavaScript uses camelCase for variables and PascalCase for classes and React components.

### Should JSON API fields be camelCase or snake_case?

There is no single standard — Google's JSON style guide says camelCase, while many Python and Rails APIs emit snake_case. Pick one convention per API and convert at the boundary.

## Related converters

- [camelCase → snake_case](https://www.devkult.com/convert/camel-to-snake.md)
- [kebab-case → camelCase](https://www.devkult.com/convert/kebab-to-camel.md)
- [snake_case → kebab-case](https://www.devkult.com/convert/snake-to-kebab.md)

Open the interactive converter: https://www.devkult.com/convert/snake-to-camel