openapi-schema-validator
OpenAPI schema validation for Python
Decision gist · record as of 2026-08-14
Yes. The package is actively maintained, has no known vulnerabilities, supports current Python versions, and fills a specific need for OpenAPI schema validation. Install it if you work with OpenAPI specs and need runtime validation; the low install friction and permissive license make it a straightforward choice. Consider it essential for API contract testing or spec-driven development.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Requires Python 3.10 or later (supports up to 3.14).
- Low install friction with a pure-Python wheel.
- Actively maintained as of 2026-07-20 with recent release activity.
License · maintenance · safety
BSD-3-Clause (permissive) — BSD-3-Clause is permissive and imposes minimal restrictions; you may use, modify, and distribute this package freely in commercial and private projects provided you include the license notice.
last release 2026-04-27 (109 days) · last repo commit 2026-07-20 · 126 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 28,129,313 downloads/mo, #839 on PyPI
Alternatives
Verify before relying
pip install openapi-schema-validator
from openapi_schema_validator import validate
schema = {"type": "object", "properties": {"name": {"type": "string"}}}
validate({"name": "John"}, schema)- Performance characteristics and typical validation latency for large or deeply nested schemas.
- Behavior and limitations when resolving external $ref references with custom registries.
- Whether the optional ecma-regex extra is required for production use cases or only for ECMAScript pattern compliance.
What it is and what it does
openapi-schema-validator is a Python library that validates instances and schemas against the OpenAPI Schema Specification. It supports three major OpenAPI versions—3.0 (which extends JSON Schema Wright Draft 00), 3.1 (which extends JSON Schema Draft 2020-12), and 3.2 (which uses the published OAS 3.2 JSON Schema dialect)—allowing you to enforce schema compliance at runtime.
The package provides version-specific validator classes (OAS30Validator, OAS31Validator, OAS32Validator) and a unified validate() function that defaults to OAS32Validator. It handles reference resolution, format validation, and property enforcement, with options to skip schema checking in hot paths, control remote reference behavior, and enforce strict property presence for contract testing. It depends on jsonschema, pydantic, and related libraries for its core validation logic.
Use it for
- Validate API request and response payloads against OpenAPI schemas in a web service or client library.
- Enforce contract testing by validating that all documented schema properties are present in responses.
- Validate configuration or data files modeled as OpenAPI schemas in a CLI tool or data pipeline.
- Check schema compliance during API spec generation or migration between OpenAPI versions.
- Validate binary or complex data types (base64, arrays with prefixItems) according to OpenAPI 3.1+ semantics.
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes.
The package is actively maintained, has no known vulnerabilities, supports current Python versions, and fills a specific need for OpenAPI schema validation. Install it if you work with OpenAPI specs and need runtime validation; the low install friction and permissive license make it a straightforward choice. Consider it essential for API contract testing or spec-driven development.
Install
openapi-schema-validator on PyPI
Before you install
Low install friction with a pure-Python wheel. Actively maintained as of 2026-07-20 with recent release activity. Depends on jsonschema, pydantic, and related validation libraries—all standard, well-maintained packages.
Requires Python 3.10 or later (supports up to 3.14).
License in practice
BSD-3-Clause is permissive and imposes minimal restrictions; you may use, modify, and distribute this package freely in commercial and private projects provided you include the license notice.
Quickstart
pip install openapi-schema-validator
from openapi_schema_validator import validate
schema = {"type": "object", "properties": {"name": {"type": "string"}}}
validate({"name": "John"}, schema)Verify before relying
- Performance characteristics and typical validation latency for large or deeply nested schemas.
- Behavior and limitations when resolving external $ref references with custom registries.
- Whether the optional ecma-regex extra is required for production use cases or only for ECMAScript pattern compliance.
Package facts
| License | BSD-3-Clause permissive |
| Python support | Supports the current Python release <4.0.0,>=3.10.0 |
| Install friction | Low. Pure-Python wheel |
| Runtime dependencies | 6 packagesjsonschemajsonschema-specificationspydanticpydantic-settingsreferencingrfc3339-validator |
| Maintenance | Actively maintained 109 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 28,129,313 / month, #839 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Development Status :: 4 - BetaIntended Audience :: DevelopersLicense :: OSI Approved :: BSD LicenseOperating System :: OS IndependentProgramming Language :: Python :: 3Programming Language :: Python :: 3.10Programming Language :: Python :: 3.11Programming Language :: Python :: 3.12Programming Language :: Python :: 3.13Programming Language :: Python :: 3.14Topic :: Software Development :: LibrariesTopic :: Software Development :: Libraries :: Python ModulesTyping :: Typed |
Evidence: openapi_schema_validator-0.9.0-py3-none-any.whl
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See also openapi-core · openapi-spec-validator · voluptuous-openapi · swagger-spec-validator · openapi3 · prance · kubernetes-validate · pyvalid · flex · aiopenapi3