---
id: types-simplejson
version: "4.1.0.20260724"
license: Apache-2.0
license_treatment: permissive
maintenance: active
---

# types-simplejson — Typing stubs for simplejson

License: permissive · Maintenance: active · Downloads: 3.7M/mo

## What it is and what it does

types-simplejson is a type stub package that provides type annotations for the simplejson library. It allows static type checkers like mypy and pyright to understand the types of simplejson functions and classes, catching type errors in code that uses simplejson before runtime. The package is generated from the typeshed project and tracks simplejson version 4.1.*.

Type stubs are metadata-only packages that don't execute code themselves—they exist solely to inform type checkers about the shape and types of another library's API. This package has no runtime dependencies and is tested against mypy 2.3.0 and pyright 1.1.411.

Use it for:

- Enable mypy or pyright to type-check code that calls simplejson.dumps() or simplejson.loads().
- Catch type mismatches in JSON serialization workflows before deployment.
- Provide IDE autocomplete and inline type hints when working with simplejson in a type-aware editor.
- Validate that JSON data structures conform to expected schemas in a typed codebase.

## Worth the install?

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

Provides type annotations for the simplejson package, enabling type checkers like mypy and pyright to validate code that uses simplejson for JSON serialization and deserialization.

Yes, if you use simplejson and want static type checking. It has no runtime cost, no dependencies, and is actively maintained as part of typeshed. Install it alongside simplejson in projects that enforce type safety. Skip it only if you don't use a type checker or don't use simplejson.

## Install

pip install types-simplejson
uv add types-simplejson
poetry add types-simplejson

## Installing types-simplejson

Before you install: Low friction installation with no runtime dependencies. Actively maintained as part of the typeshed project, with recent releases and a current status.

License in practice: Licensed under Apache-2.0 (permissive), allowing use in both open-source and proprietary projects without significant restrictions.

Quickstart:

pip install types-simplejson

import simplejson
data = simplejson.dumps({"key": "value"})

Requires Python 3.10 or later.

Verify before relying:

- Whether this package is automatically discovered by type checkers or requires explicit configuration in pyproject.toml or similar.
- Coverage completeness for all simplejson APIs in version 4.1.*.

## Package facts

- License: Apache-2.0 (permissive)
- Python support: supports_current
- Install friction: low
- Maintenance: active
- Downloads: 3.7M/month (top 5,000 on PyPI)
- Known vulnerabilities: none known

## Tags

type stubs simplejson, simplejson type hints, mypy simplejson annotations, pyright type checking json, typing stubs for simplejson, static type checking json library, type-stubs, static-analysis

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