🔑 JSON Key Renamer

What Can the JSON Key Renamer Do?

The JSON Key Renamer is a free online tool for batch renaming keys in JSON objects. It supports conversion between camelCase, snake_case, kebab-case, PascalCase, and CONSTANT_CASE naming styles, as well as custom key mappings for precise control. The tool recursively traverses nested objects and arrays, renaming all matching keys at every level. All processing runs locally in your browser with no server uploads.

Core Features

• Style Conversion: One-click conversion between camelCase, snake_case, kebab-case, PascalCase, and CONSTANT_CASE
• Custom Mappings: Manually specify old key → new key mappings for precise control
• Deep Traversal: Recursively processes nested objects and arrays at all levels
• Real-time Preview: Results update automatically as you modify input or options
• Multi-format Export: Copy results or download as JSON file
• Statistics: Shows renamed key count and total key count

How to Use

1. Paste JSON content in the input box, or click "Load Example".

2. Choose conversion mode: Style Conversion (automatic) or Custom Mapping (manual).

3. Select target style or add custom key mappings.

4. Click "Convert" to see the result.

5. Click "Copy Result" or "Download JSON" to export.

Use Cases

Case 1: Frontend-Backend Data Alignment

Backend returns snake_case JSON, frontend needs camelCase — one-click conversion saves manual editing.

Case 2: Database Field Mapping

Database fields use snake_case, APIs need camelCase output — batch convert JSON keys.

Case 3: Code Refactoring

Unify naming conventions during refactoring by batch converting JSON config styles.

Case 4: Third-party API Adaptation

When third-party API key names don't match your project conventions, use custom mappings for precise conversion.

Extended Knowledge

JSON key naming conventions vary across languages and frameworks: JavaScript/Java prefer camelCase, Python/Ruby prefer snake_case, CSS/URLs prefer kebab-case, C# prefers PascalCase, and constants use CONSTANT_CASE. In frontend-backend separation, backends typically use snake_case (database field style) while frontends use camelCase (JavaScript convention), requiring a data layer transformation. Common conversion rules: snake_case splits on underscores and capitalizes subsequent words for camelCase; camelCase inserts underscores before uppercase letters and lowercases for snake_case.