Comparing JSON Differences in Python Using json_tools and a Custom Recursive Method

During testing, manually comparing two JSON strings is time‑consuming, so an automated way to detect differences is essential.

The first approach leverages the third‑party Python library json_tools. After installing it with pip install json_tools, you can call its comparison function, which produces a list of change dictionaries such as

[{'replace': '/right', 'value': 'R', 'prev': 'r'}, {'remove': '/box', 'prev': 'b'}, {'add': '/boxs', 'value': 'box'}]

.

The output uses keys like replace (indicating a modified value), add (a newly added key), and remove (a deleted key); each entry also contains the new value ( value) and the previous value ( prev) when applicable.

The second approach is a custom recursive function written by the author, capable of handling deeply nested JSON structures. Its sample output looks like

[{'replace': '/left', 'value': 5, 'prev': 6}, {'add': '/right/ads/des', 'value': '新增键'}, {'remove': '/box/3', 'prev': {'id': 4, 'title': '标题4'}, 'details': 'array-item'}]

, where paths such as /right/ads/des represent nested keys.

Both methods have trade‑offs: using json_tools is straightforward but yields a fixed output format, while the recursive solution offers flexible, customizable reporting at the cost of additional implementation effort.

Overall, the article provides practical guidance for Python developers who need to compare JSON data efficiently in automated tests.