spectree
Generate OpenAPI document and validate request & response with Python annotations.
Decision gist · record as of 2026-08-14
Yes. SpecTree is actively maintained, has no known vulnerabilities, and installs with minimal friction. It solves a real problem—keeping API documentation synchronized with code—and does so without requiring separate YAML files. The single pydantic dependency is lightweight and widely used. It's most valuable if you're building REST APIs with one of the four supported frameworks and want automatic OpenAPI generation with request/response validation.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Requires Python 3.10 or later.
- Requires one of the supported web frameworks (Flask, Quart, Falcon, or Starlette) to be installed separately.
- Low install friction with a single runtime dependency (pydantic).
License · maintenance · safety
Apache-2.0 (permissive) — Licensed under Apache-2.0 (permissive), allowing commercial and private use with minimal restrictions.
last release 2025-12-16 (241 days) · last repo commit 2026-08-10 · 362 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 374,170 downloads/mo, #7,148 on PyPI
Alternatives
Verify before relying
pip install spectree
from spectree import SpecTree, Response
from pydantic import BaseModel
api = SpecTree('flask')
class QueryModel(BaseModel):
name: str
@api.validate(query=QueryModel, resp=Response(HTTP_200=None))
def hello(query: QueryModel):
return {'message': f'Hello {query.name}'}
api.register(app)
# API docs at /apidoc/redoc, /apidoc/swagger, or /apidoc/scalar- Whether offline mode (spectree[offline]) works reliably with all supported frameworks and UI options.
- Performance characteristics when validating large request/response payloads or high request volumes.
- Compatibility with frameworks beyond the four explicitly listed (Flask, Quart, Falcon, Starlette).
What it is and what it does
SpecTree is a Python library that bridges type annotations and OpenAPI specification generation. It uses pydantic models to define request and response schemas, then automatically generates OpenAPI documents and serves them via interactive UI (Redoc, Swagger, or Scalar). The library works as a decorator-based validator that intercepts HTTP requests to your web application, validates query parameters, JSON bodies, headers, and cookies against your pydantic models, and validates responses before they're sent to clients.
The library is framework-agnostic at its core but provides integrations for Flask, Quart, Falcon, and Starlette. You define your data structures once as pydantic BaseModels, decorate your route handlers with @api.validate(), and SpecTree handles both validation and documentation generation. Failed validations return 422 status with structured error details. It supports security schemes (API keys, OAuth2), deprecated endpoints, tags, and custom response codes.
Use it for
- Build REST APIs with automatic OpenAPI documentation by decorating endpoints with pydantic model validators.
- Validate incoming query strings, JSON payloads, headers, and cookies against strict schemas without manual parsing.
- Generate interactive API documentation (Swagger UI, Redoc, or Scalar) that stays in sync with your code.
- Enforce response validation to catch serialization errors before they reach clients.
- Define API security schemes (API keys, OAuth2) and enforce them per-endpoint or globally.
- Skip boilerplate YAML configuration by deriving OpenAPI specs directly from Python type annotations.
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes.
SpecTree is actively maintained, has no known vulnerabilities, and installs with minimal friction. It solves a real problem—keeping API documentation synchronized with code—and does so without requiring separate YAML files. The single pydantic dependency is lightweight and widely used. It's most valuable if you're building REST APIs with one of the four supported frameworks and want automatic OpenAPI generation with request/response validation.
Install
spectree on PyPI
Before you install
Low install friction with a single runtime dependency (pydantic). Actively maintained with recent commits and modern Python support (3.10+). No known vulnerabilities.
Requires Python 3.10 or later. Requires one of the supported web frameworks (Flask, Quart, Falcon, or Starlette) to be installed separately.
License in practice
Licensed under Apache-2.0 (permissive), allowing commercial and private use with minimal restrictions.
Quickstart
pip install spectree
from spectree import SpecTree, Response
from pydantic import BaseModel
api = SpecTree('flask')
class QueryModel(BaseModel):
name: str
@api.validate(query=QueryModel, resp=Response(HTTP_200=None))
def hello(query: QueryModel):
return {'message': f'Hello {query.name}'}
api.register(app)
# API docs at /apidoc/redoc, /apidoc/swagger, or /apidoc/scalarVerify before relying
- Whether offline mode (spectree[offline]) works reliably with all supported frameworks and UI options.
- Performance characteristics when validating large request/response payloads or high request volumes.
- Compatibility with frameworks beyond the four explicitly listed (Flask, Quart, Falcon, Starlette).
Package facts
| License | Apache-2.0 permissive |
| Python support | Supports the current Python release >=3.10 |
| Install friction | Low. Pure-Python wheel |
| Runtime dependencies | 1 packagepydantic |
| Maintenance | Actively maintained 241 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 374,170 / month, #7,148 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Intended Audience :: DevelopersOperating System :: OS IndependentProgramming Language :: Python :: 3 :: OnlyProgramming Language :: Python :: 3.10Programming Language :: Python :: 3.11Programming Language :: Python :: 3.12Programming Language :: Python :: 3.13Programming Language :: Python :: 3.14Programming Language :: Python :: Free ThreadingProgramming Language :: Python :: Implementation :: CPythonTopic :: Software Development :: Libraries :: Python Modules |
Evidence: spectree-2.0.1-py3-none-any.whl
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