Show HN: Plain – A full-stack Python framework designed for humans and agents

Plain is a Python web framework for building apps, emphasizing an explicit / typed / predictable design. It aims for a structure that is easy for humans to understand and stable enough for agents to handle automatically.

The key features are as follows.

• Models are declared with @postgres.register_model, type hints, and field objects.
• Views are written in a class-based style.
• URLs are organized with the Router class.
• Packages for ORM, auth, sessions, jobs, email, admin, and frontend are included within the framework.

Agent-friendliness is strongly emphasized. Projects include Rules, an automation rule file, along with Docs accessible from the command line and Skills that shorten workflows. For example, topics like models, querysets, and search can be looked up directly via plain docs.

The CLI is also a major pillar of the framework.

• plain dev runs a dev server including HTTPS
• plain fix cleans up Python, CSS, and JS all at once
• plain check verifies lint, preflight, migration, and test
• plain test runs pytest

The tech stack is centered on Python 3.13+, Postgres, Jinja2, htmx, and Tailwind CSS. Package management uses uv, linting and formatting use ruff and oxc, type checking uses ty, and bundling uses esbuild.

In summary, Plain is a framework that aims to preserve the productivity feel of the traditional Django lineage while increasing type safety and explicitness, providing a structure that makes it easy for humans and AI agents to work together.