Files Edit JSON

Edit JSON with a Python library, never by hand

Overview

Build and edit JSON by round-tripping through a Python data structure, then re-load to confirm it parses. Editing JSON as raw text invites the classic breakages: a trailing comma, an unquoted key, a single quote, a missing brace. A library serialization is valid by construction; re-loading it verifies it.

Library

• json (stdlib) - the default: json.load / json.dump (use indent=2 for human-edited config, ensure_ascii=False to keep literal UTF-8 instead of \uXXXX, sort_keys=True for stable diffs). Correct and always available.
• orjson - when speed/throughput matters (fast, returns bytes, strict). pip install orjson.

JSON has no comments. If a file has // or /* */ (JSONC, e.g. tsconfig, VS Code settings) or trailing commas (JSON5), plain json will fail - use pyjson5/json5 to load it, but write back as strict JSON unless the consumer requires the relaxed form.

See bitranox:coding-python-use-modern-libraries for the wider list. Reach for the structured editors for the other formats too: bitranox:files-edit-toml, bitranox:files-edit-xml, bitranox:files-edit-yml.

Pattern: load -> edit the structure -> dump -> re-load to validate

import json
from pathlib import Path

path = Path("plugins/bitranox/.claude-plugin/plugin.json")
data = json.loads(path.read_text(encoding="utf-8"))   # parse into Python objects

data["version"] = "1.5.0"                              # edit the structure

path.write_text(json.dumps(data, indent=2) + "\n", encoding="utf-8")  # serialize back

# validate: re-load and assert (raises JSONDecodeError if malformed)
assert json.loads(path.read_text(encoding="utf-8"))["version"] == "1.5.0"

For a quick syntax check of any JSON file without editing: python3 -c "import json,sys; json.load(open(sys.argv[1])); print('ok')" file.json

Common mistakes