What is JSON deep merge?

JSON deep merge (recursive merge) not only combines the top-level properties of two objects but also recursively merges nested objects. For properties with the same name, if both are object types, their properties are recursively merged; if they are other types (such as arrays, strings, etc.), the latter value will overwrite the former.

When should I use deep merge?

You should use deep merge when you need to merge two configuration objects with nested structures and want the properties of nested objects to be merged rather than completely replaced. For example, when merging default configurations with user custom configurations, deep merge can preserve nested properties in the default configuration that are not overridden.

Does deep merge modify the original data?

No. Deep merge does not modify the two input JSON objects but creates a new object as the merge result. The original data remains unchanged, and you can safely perform multiple merge operations.

How does deep merge handle circular references?

The current version of the deep merge tool does not support handling JSON objects containing circular references. If the input data contains circular references, it may cause errors. Please ensure that the input JSON objects are standard structures without circular references.

How is the performance of deep merge?

Deep merge needs to recursively traverse all nested levels of objects, so for deeply nested large objects, performance will be slightly lower than simple merge. For most practical application scenarios (such as configuration file merging), performance is good. If you encounter performance issues, consider simplifying the data structure.

JSON Deep Merge Tool Online - EXUtil Extended Utilities

Free online JSON deep merge tool. Recursively merge two JSON objects with nested objects being deeply merged rather than simply replaced, ideal for merging complex nested configurations.

How to use

Paste or import the content you want to process.
Choose an available action and run the tool.
Review the result, then copy or download the output.

Frequently asked questions

What is JSON deep merge?: JSON deep merge (recursive merge) not only combines the top-level properties of two objects but also recursively merges nested objects. For properties with the same name, if both are object types, their properties are recursively merged; if they are other types (such as arrays, strings, etc.), the latter value will overwrite the former.
When should I use deep merge?: You should use deep merge when you need to merge two configuration objects with nested structures and want the properties of nested objects to be merged rather than completely replaced. For example, when merging default configurations with user custom configurations, deep merge can preserve nested properties in the default configuration that are not overridden.
Does deep merge modify the original data?: No. Deep merge does not modify the two input JSON objects but creates a new object as the merge result. The original data remains unchanged, and you can safely perform multiple merge operations.
How does deep merge handle circular references?: The current version of the deep merge tool does not support handling JSON objects containing circular references. If the input data contains circular references, it may cause errors. Please ensure that the input JSON objects are standard structures without circular references.
How is the performance of deep merge?: Deep merge needs to recursively traverse all nested levels of objects, so for deeply nested large objects, performance will be slightly lower than simple merge. For most practical application scenarios (such as configuration file merging), performance is good. If you encounter performance issues, consider simplifying the data structure.