Python Validation

Open-source Python projects categorized as Validation

Top 23 Python Validation Projects

  1. pydantic

    Data validation using Python type hints

    Project mention: A Practical Guide on Structuring LLM Outputs with Pydantic | dev.to | 2025-06-12

    The solution? Leverage Pydantic, a Python library that enables runtime data validation using type annotations.

  2. InfluxDB

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  3. instructor

    structured outputs for llms

    Project mention: Generative AI: A Personal Deep Dive – My Notes and Insights Part-2 | dev.to | 2024-12-21

    For those looking for an even easier way to manage structured outputs, the Instructor library is a fantastic tool. Instructor is built on top of Pydantic and aims to simplify the process of getting structured data like JSON from LLMs.

  4. marshmallow

    A lightweight library for converting complex objects to and from simple Python datatypes.

  5. jsonschema

    An implementation of the JSON Schema specification for Python

  6. pandera

    A light-weight, flexible, and expressive statistical data testing library

  7. msgspec

    A fast serialization and validation library, with builtin support for JSON, MessagePack, YAML, and TOML

    Project mention: Don't let dicts spoil your code | news.ycombinator.com | 2024-10-09

    gjson [1] and a few other go packages offer a way to parse arbitrary JSON without requiring structs to hold them.

    re: Python. I like PyRight/PyLance for Python typing, it seems to "just work" afaict. I also like msgspec for dataclass like behavior [2].

    ---

    1: https://github.com/tidwall/gjson

    2: https://jcristharif.com/msgspec/

  8. Schematics

    Python Data Structures for Humans™.

  9. SaaSHub

    SaaSHub - Software Alternatives and Reviews. SaaSHub helps you find the best software and product alternatives

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  10. pydantic-core

    Core validation logic for pydantic written in rust

  11. strictyaml

    Type-safe YAML parser and validator.

    Project mention: StrictYAML | news.ycombinator.com | 2025-03-07
  12. WTForms

    A flexible forms validation and rendering library for Python.

  13. webargs

    A friendly library for parsing HTTP request arguments, with built-in support for popular web frameworks, including Flask, Django, Bottle, Tornado, Pyramid, webapp2, Falcon, and aiohttp.

  14. python-email-validator

    A robust email syntax and deliverability validation library for Python.

  15. Deal

    🤝 Design by contract for Python. Write bug-free code. Add a few decorators, get static analysis and tests for free.

  16. enforce

    Python 3.5+ runtime type checking for integration testing and data validation

  17. colander

    A serialization/deserialization/validation library for strings, mappings and lists.

  18. fastopenapi

    FastOpenAPI is a library for generating and integrating OpenAPI schemas using Pydantic v2 and various frameworks (AioHttp, Falcon, Flask, Quart, Sanic, Starlette, Tornado).

    Project mention: FastOpenAPI: A Reason to Believe in Open Source Community | dev.to | 2025-04-18

    Repository: GitHub

  19. flask-pydantic

    flask extension for integration with the awesome pydantic package

  20. openapi-spec-validator

    OpenAPI Spec Validator is a CLI, pre-commit hook and python package that validates OpenAPI Specs against the OpenAPI 2.0 (aka Swagger), OpenAPI 3.0 and OpenAPI 3.1 specification.

  21. pydantic-to-typescript

    CLI Tool for converting pydantic models into typescript definitions

  22. apischema

    JSON (de)serialization, GraphQL and JSON schema generation using Python typing.

  23. aiohttp-apispec

    Build and document REST APIs with aiohttp and apispec

  24. phantom-types

    Phantom types for Python.

  25. koda-validate

    Typesafe, Composable Validation

  26. SaaSHub

    SaaSHub - Software Alternatives and Reviews. SaaSHub helps you find the best software and product alternatives

    SaaSHub logo
NOTE: The open source projects on this list are ordered by number of github stars. The number of mentions indicates repo mentiontions in the last 12 Months or since we started tracking (Dec 2020).

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Python Validation related posts

  • A Practical Guide on Structuring LLM Outputs with Pydantic

    2 projects | dev.to | 12 Jun 2025
  • Advanced Pydantic: Generic Models, Custom Types, and Performance Tricks

    1 project | dev.to | 5 May 2025
  • Exploring the Instructor Library: Structuring Unstructured Data (and Some Fun along the Way)

    1 project | dev.to | 16 Nov 2024
  • Tactics for multi-step LLM app experimentation

    1 project | dev.to | 25 Jul 2024
  • Checkbox Extraction from PDFs - A Tutorial

    3 projects | dev.to | 16 Jul 2024
  • Table Extraction and Processing from PDFs - A Tutorial

    3 projects | dev.to | 11 Jul 2024
  • JSON extra uses orjson instead of ujson

    4 projects | news.ycombinator.com | 5 Jun 2024
  • A note from our sponsor - InfluxDB
    www.influxdata.com | 17 Jun 2025
    InfluxDB 3 OSS is now GA. Transform, enrich, and act on time series data directly in the database. Automate critical tasks and eliminate the need to move data externally. Download now. Learn more →

Index

What are some of the best open-source Validation projects in Python? This list will help you:

# Project Stars
1 pydantic 24,143
2 instructor 10,732
3 marshmallow 7,150
4 jsonschema 4,772
5 pandera 3,854
6 msgspec 2,935
7 Schematics 2,580
8 pydantic-core 1,607
9 strictyaml 1,546
10 WTForms 1,545
11 webargs 1,395
12 python-email-validator 1,269
13 Deal 804
14 enforce 545
15 colander 457
16 fastopenapi 416
17 flask-pydantic 392
18 openapi-spec-validator 359
19 pydantic-to-typescript 355
20 apischema 234
21 aiohttp-apispec 220
22 phantom-types 219
23 koda-validate 119

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