json-e

What it is and what it does

json-e is a parameterization system for embedding context and dynamic expressions into JSON objects. It lets you define JSON structures with placeholders and variables that are resolved at runtime, making it useful for templating, configuration generation, and data transformation workflows where you need to inject computed values or external context into JSON without writing custom parsing code.

The package is a pure Python library with no external runtime dependencies, making it lightweight and easy to integrate. It has been actively maintained since its first release on 2017-07-06 and receives regular updates; the latest version 4.8.2 is from 2026-02-26. It ranks in the top 5000 PyPI packages by download volume and carries no known security vulnerabilities.

Use it for:

• Generate configuration files dynamically by embedding environment variables or computed values into JSON templates.
• Transform task definitions or workflow specifications by parameterizing JSON structures with runtime context.
• Build data pipelines where JSON payloads need to be enriched with computed fields or external state before processing.
• Create reusable JSON schemas that accept parameters for different deployment or execution contexts.
• Embed expressions into JSON documents for conditional logic or computed field values during deserialization.

Worth the install?

AI-flagged interpretation of the facts on this page — verify before relying

Parameterizes and transforms JSON data structures by embedding context and variables into JSON objects, enabling dynamic data manipulation without external dependencies.

Yes. Low install friction, no dependencies, active maintenance, and no known security vulnerabilities make it a safe choice. The copyleft license (MPL2) is a consideration for proprietary projects but not a blocker for open-source use. Install it if you need JSON templating or parameterization; the lightweight nature and established maintenance history support reliable production use.

Install

json-e on PyPI

pip install json-e

uv add json-e

poetry add json-e

Installing json-e

Before you install

Low friction: pure Python wheel with no runtime dependencies. Active maintenance as of 169 days ago.

License in practice

MPL2 is a copyleft license requiring derivative works to disclose source and license under the same terms; suitable for open-source projects but may constrain proprietary use.

Quickstart

pip install json-e
import json_e

Verify before relying

• Whether the package supports modern Python versions (requires_python is unspecified in the fact sheet)
• Specific transformation capabilities and syntax (the fact sheet references external docs but does not detail the feature set)
• Whether the usage example syntax is accurate without access to the package's actual API documentation

Package facts

Evidence: json_e-4.8.2-py3-none-any.whl

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