Introduction

Kernia is a Python authentication package for teams building SaaS products with FastAPI, Starlette, Django, SQLAlchemy, Mongo, Redis storage, Stripe billing, and enterprise identity requirements.

Kernia is compatible with the Better Auth wire protocol where clients depend on route shape, cookie behavior, and JSON payloads. The public Python surface is Kernia: packages use kernia-*, imports use kernia_*, and the CLI command is kernia.

What Kernia gives you

How it fits together

from kernia import KerniaOptions
from kernia.auth import init
from kernia.plugins.organization import organization
from kernia.plugins.api_key import api_key

auth = init(KerniaOptions(
    database=adapter,
    secret=env.KERNIA_SECRET,
    base_url=env.KERNIA_BASE_URL,
    plugins=[
        organization(),
        api_key(),
    ],
))

Framework packages mount the auth instance. Browser clients call the mounted routes. Adapters persist users, sessions, accounts, verification tokens, and plugin tables.

Design goals

• Python-first server packages and imports.
• Compatibility at the HTTP and cookie boundary where clients rely on it.
• Real adapters and migrations instead of demo-only storage.
• Plugin docs that identify routes, schema, options, and test coverage.
• SaaS demo flows that call the backend and show not-configured states honestly.

Documentation model

Each feature page explains installation, server configuration, client usage, routes, schema changes, options, examples, troubleshooting, and test or demo coverage. Pages do not claim support for a provider or plugin unless the repo exposes that package or the page clearly marks it as a compatibility or configuration pattern.

Start here

1. Read Installation to create a Python project.
2. Read Basic Usage to mount Kernia on FastAPI.
3. Open FastAPI SaaS Demo for the reference app.
4. Open Stripe for billing, entitlements, and usage tracking.
5. Open Testing before declaring a plugin or adapter production-ready.