---
id: zope-schema
version: "8.1"
license: ZPL-2.1
license_treatment: unclear
maintenance: aging
---

# zope.schema — zope.interface extension for defining data schemas

License: unclear · Maintenance: aging · Downloads: 994.6K/mo

## What it is and what it does

zope.schema extends zope.interface to provide a declarative way to define structured data schemas for Python objects. Instead of just describing methods, schemas define the public fields (attributes) of an object, each with a title, description, constraints, and validation logic. A field roughly maps to an object attribute but adds metadata and validation capabilities—you can mark fields as read-only, optional, or required, apply constraints, and define custom validation methods.

The package is used to build self-documenting, validated object models in frameworks that rely on the Zope ecosystem. It provides field types for common data (text, numbers, dates, objects, collections) and allows you to attach invariant validators to schemas to enforce cross-field constraints. The validation framework raises specific exceptions that applications can catch and handle.

Use it for:

- Define validated data models for web frameworks or APIs that need structured input validation and self-documenting schemas.
- Build form generation systems that automatically create HTML forms from schema definitions with validation.
- Enforce object invariants and cross-field constraints in domain models where simple type hints are insufficient.
- Create reusable field libraries for applications that need consistent validation rules across multiple object types.
- Generate documentation or introspection metadata from schema definitions for API clients or configuration systems.

## Worth the install?

AI-flagged interpretation of the facts above — verify before relying.

Defines structured data schemas for Python objects using interface-based field definitions with validation, constraints, and metadata.

Yes, if you are already using the Zope ecosystem or need declarative, interface-based schema validation. The package is stable (Production/Stable status), has no known vulnerabilities, and supports Python 3.9, 3.10, 3.11, 3.12, 3.13. However, the aging maintenance status and unclear license treatment warrant review before adoption in new projects outside the Zope community.

## Install

pip install zope-schema
uv add zope-schema
poetry add zope-schema

## Installing zope.schema

Before you install: Low install friction with only two runtime dependencies (zope.interface and zope.event). Maintenance status is aging—last release was 292 days ago—but the package remains actively supported with recent Python version coverage and no known vulnerabilities.

License in practice: Licensed under ZPL-2.1 (Zope Public License 2.1), which is OSI-approved but less common than MIT or Apache 2.0. The license treatment is marked unclear, so review the full license terms before use in proprietary or copyleft-sensitive projects.

Quickstart:

from zope.schema import TextLine, Int, Object
from zope.interface import Interface

class IPerson(Interface):
    name = TextLine(title="Name", required=True)
    age = Int(title="Age")

Requires Python 3.9 or later; zope.interface and zope.event must be installed as runtime dependencies.

Verify before relying:

- Whether the package is actively maintained or in long-term support mode given the 292-day gap since last release.
- Performance characteristics when validating large or deeply nested object hierarchies.
- Compatibility with modern async frameworks or whether it is synchronous-only.

## Package facts

- License: ZPL-2.1 (unclear)
- Python support: supports_current
- Install friction: low
- Maintenance: aging
- Downloads: 994.6K/month (top 5,000 on PyPI)
- Known vulnerabilities: none known

## Tags

python schema validation, interface field definitions, data schema framework, zope interface schemas, structured object validation, field constraints and metadata, python object schema, schema-validation, zope-ecosystem, interface-driven

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