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Show HN: Oxyde – Pydantic-native async ORM with a Rust core
Hi HN! I built Oxyde because I was tired of duplicating my models.
If you use FastAPI, you know the drill. You define Pydantic models for your API, then define separate ORM models for your database, then write converters between them. SQLModel tries to fix this but it's still SQLAlchemy underneath. Tortoise gives you a nice Django-style API but its own model system. Django ORM is great but welded to the framework.
I wanted something simple: your Pydantic model IS your database model. One class, full validation on input and output, native type hints, zero duplication. The query API is Django-style (.objects.filter(), .exclude(), Q/F expressions) because I think it's one of the best designs out there.
Explicit over implicit. I tried to remove all the magic. Queries don't touch the database until you call a terminal method like .all(), .get(), or .first(). If you don't explicitly call .join() or .prefetch(), related data won't be loaded. No lazy loading, no surprise N+1 queries behind your back. You see exactly what hits the database by reading the code.
Type safety was a big motivation. Python's weak spot is runtime surprises, so Oxyde tackles this on three levels: (1) when you run makemigrations, it also generates .pyi stub files with fully typed queries, so your IDE knows that filter(age__gte=...) takes an int, that create() accepts exactly the fields your model has, and that .all() returns list[User] not list[Any]; (2) Pydantic validates data going into the database; (3) Pydantic validates data coming back out via model_validate(). You get autocompletion, red squiggles on typos, and runtime guarantees, all from the same model definition.
Why Rust? Not for speed as a goal. I don't do "language X is better" debates. Each one is good at what it was made for. Python is hard to beat for expressing business logic. But infrastructure stuff like SQL generation, connection pooling, and row serialization is where a systems language makes sense. So I split it: Python handles your models and business logic, Rust handles the database plumbing. Queries are built as an IR in Python, serialized via MessagePack, sent to Rust which generates dialect-specific SQL, executes it, and streams results back. Speed is a side effect of this split, not the goal. But since you're not paying a performance tax for the convenience, here are the benchmarks if curious: https://oxyde.fatalyst.dev/latest/advanced/benchmarks/ https://oxyde.fatalyst.dev/latest/advanced/benchmarks/
What's there today: Django-style migrations (makemigrations / migrate), transactions with savepoints, joins and prefetch, PostgreSQL + SQLite + MySQL, FastAPI integration, and an auto-generated admin panel that works with FastAPI, Litestar, Sanic, Quart, and Falcon (https://github.com/mr-fatalyst/oxyde-admin https://github.com/mr-fatalyst/oxyde-admin).
It's v0.5, beta, active development, API might still change. This is my attempt to build the ORM I personally wanted to use. Would love feedback, criticism, ideas.
Docs: https://oxyde.fatalyst.dev/ https://oxyde.fatalyst.dev/
Step-by-step FastAPI tutorial (blog API from scratch): https://github.com/mr-fatalyst/fastapi-oxyde-example https://github.com/mr-fatalyst/fastapi-oxyde-example
- throwawayffffas 7mo agoLol I never knew django orm is faster than SQLAlchemy. But having used both that makes sense. > Why Rust? ... Rust handles the database plumbing. Queries are built as an IR in Python, serialized via MessagePack, sent to Rust which generates dialect-specific SQL, executes it, and streams results back. Speed is a side effect of this split, not the goal. Nice. So what does it take to deploy this, dependency wise?
- mr_Fatalyst 7mo agoJust pip install oxyde, that's it. The Rust core (oxyde-core) ships as pre-built wheels for Linux, macOS, and Windows, so no Rust toolchain needed. Python-side dependencies are just pydantic, msgpack, and typer for the CLI. Database drivers are bundled in the Rust core (uses sqlx under the hood), so you don't need to install asyncpg/aiosqlite/etc separately either.
- unrealhoang 7mo agoa bit tangent question: the communication between Python & Rust, could the pyo3 ser/de of Python objects be better than MsgPack?
- mr_Fatalyst 7mo agoGood question. Working with Python objects in PyO3 requires holding the GIL. With MessagePack, Python serializes to bytes, hands them off, and Rust works completely GIL-free from that point. Same on the way back. So the GIL is held only for the brief serde step, not during SQL generation or execution.
- zbentley 7mo agoI’m curious: why was this marked dead?
- kstrauser 7mo ago> Lol I never knew django orm is faster than SQLAlchemy. I don’t believe that for a second. Both are wonderful projects, but raw performance was never one of Django ORM’s selling points. I think its real advantage is making it easy to model new projects and make efficient CRUD calls on those tables. Alchemy’s strong point is “here’s an existing database; let users who grok DB theory query it as efficiently and ergonomically as possible.”