JSON Transformer – Reshape JSON Structures Online
Transform JSON structure using user-defined rules and key mappings. Our free JSON Transformer is perfect for reshaping API responses to match your application's data model.
About JSON Transformer
API responses rarely match your application data model exactly. Renaming keys, extracting nested values, and reshaping structures manually is repetitive work. This JSON Transformer lets you define rules to copy, rename, and transform JSON paths into your desired output structure.
How it works
Paste your JSON into the Input area. Add transformation rules specifying Source Path, Target Path, and Operation. Choose from Copy, Rename, Uppercase, Lowercase, or Delete operations. Click Transform to apply all rules and see the reshaped result.
Use dot notation for nested paths like user.profile.name. Add multiple rules to build complex transformations. The Load Sample button demonstrates renaming firstName to name.first and lowercasing email values in one transformation.
When you'd use this
Frontend developers adapting third-party API responses to match component props save significant time. Data engineers normalizing JSON from multiple sources into a unified schema benefit from repeatable transformation rules.
This tool handles structural transformations, not complex data manipulation. For calculations, filtering, or conditional logic, use a programming language. The transformer works best for consistent reshaping tasks.
Questions
How do I reference nested values?
Use dot notation like user.address.city for nested objects and array[index] for array items.
Can I delete fields?
Yes. Use the Delete operation to exclude fields from the output entirely.
What does Rename do?
Rename copies a value to a new path with a different key name, effectively renaming the field.
Do string operations chain?
No. Each rule operates on the original input. Apply Uppercase or Lowercase directly to the source value.
Can I save transformation rules?
Rules are not persisted. Copy your rule configuration for reuse or bookmark this page with your rules in browser storage.