JsonPatchX

JSON Patch for modern PATCH APIs. Tested against the RFC 6902 Compliance Test Suite.

Built on Pydantic models, with typed JSON Pointer / JSONPath targeting, custom patch operations, and first-class support for FastAPI PATCH routes and OpenAPI generation.

Table of Contents

• Install
• Links
• Examples
• Contributing
• License
• Contact
• Acknowledgements

Install

pip install jsonpatchx

For FastAPI integrations:

pip install jsonpatchx[fastapi]

Links

• Documentation: https://angela-tarantula.github.io/jsonpatchx/user-guide/getting-started
• Chengelog: https://github.com/angela-tarantula/jsonpatchx/blob/main/CHANGELOG.md
• PyPI: https://pypi.org/project/jsonpatchx
• Source code: https://github.com/angela-tarantula/jsonpatchx
• Issue tracker: https://github.com/angela-tarantula/jsonpatchx/issues
• Project Discussions: https://github.com/angela-tarantula/jsonpatchx/discussions
• IETF Future Standards Discussions: https://github.com/json-patch/json-patch2

Examples

1. Standard RFC 6902

from jsonpatchx import JsonPatch

doc = {"name": "Ada", "roles": ["engineer"]}

patch = JsonPatch.from_string(
    """
    [
      {"op": "replace", "path": "/name", "value": "Ada Lovelace"},
      {"op": "add", "path": "/roles/-", "value": "maintainer"}
    ]
    """
)

updated = patch.apply(doc)

2. The FastAPI Contract

from fastapi import FastAPI
from pydantic import BaseModel, EmailStr
from jsonpatchx import JsonPatchFor

class User(BaseModel):
    id: int
    email: EmailStr
    active: bool

app = FastAPI()

@app.patch("/users/{user_id}", response_model=User)
def patch_user(user_id: int, patch: JsonPatchFor[User]) -> User:
    user = load_user(user_id)
    updated = patch.apply(user)
    save_user(user_id, updated)
    return updated

Note: For custom operations, JSONPath targeting, route-level controls, and more, see the User Guide.

Contributing

See CONTRIBUTING.md for local setup, checks, docs preview, and pull request expectations.

Use Discussions for project-specific design conversation, issues for concrete bugs or proposed work, and the broader json-patch2 forum for standards discussion.

License

Distributed under the MIT License. See LICENSE for more information.

Contact

Angela Liss - chamsester@gmail.com

Project Link: https://github.com/angela-tarantula/jsonpatchx

Acknowledgements

Thanks to these foundational projects:

• Pydantic
• FastAPI
• python-json-pointer
• python-jsonpath

And to these excellent alternatives:

• py_yyjson
• json-merge-patch
• python-json-patch