NexusX

Install

pip install nexusx
pip install nexusx[fastmcp]  # with MCP support

Requires Python ≥ 3.10.

Quick Start

Step 1 — Entities + GraphQL

from sqlmodel import SQLModel, Field, Relationship, select
from nexusx import query, mutation, GraphQLHandler

class User(SQLModel, table=True):
    id: int | None = Field(default=None, primary_key=True)
    name: str
    posts: list["Post"] = Relationship(back_populates="author")

    @query
    async def get_users(cls, limit: int = 10) -> list["User"]:
        async with get_session() as session:
            return (await session.exec(select(cls).limit(limit))).all()

class Post(SQLModel, table=True):
    id: int | None = Field(default=None, primary_key=True)
    title: str
    author_id: int = Field(foreign_key="user.id")
    author: User | None = Relationship(back_populates="posts")

handler = GraphQLHandler(base=SQLModel, session_factory=async_session)

Relationships resolve automatically — DataLoader batches queries, one SQL per level:

{ userGetUsers(limit: 5) { name posts { title } } }

Step 2 — Typed REST with DTOs

from nexusx import DefineSubset, ErManager

class UserDTO(DefineSubset):
    __subset__ = (User, ("id", "name"))

class PostDTO(DefineSubset):
    __subset__ = (Post, ("id", "title", "author_id"))
    author: UserDTO | None = None  # auto-loaded — field name matches relationship

Resolver = ErManager(base=SQLModel, session_factory=async_session).create_resolver()
dtos = await Resolver().resolve(posts)

DefineSubset is GraphQL field selection in Python — declare which fields you want, get a typed DTO. Relationship fields auto-load when the name matches. Add resolve_* for custom loading, post_* for derived fields.

Step 3 — MCP + REST from business logic

```python from nexusx import UseCaseService, UseCaseAppConfig, create_use_case_mcp_server, create_use_case_router

class SprintService(UseCaseService): @query async def list_sprints(cls) -> list[SprintSummary]: """Get all sprints with task counts.""" ...

config = UseCaseAppConfig(name="project", services=[SprintService])

Demos

git clone https://github.com/allmonday/nexusx.git && cd nexusx && bash start_all.sh

How It Compares