JSON-log-formatter
JSON log formatter
Decision gist · record as of 2026-08-14
Yes. The package is lightweight, dependency-free, actively maintained, and solves a concrete problem—structured JSON logging is now standard practice for production systems. Install it if you're already using Python's logging module and need JSON output for log aggregation or cloud platforms.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Requires Python 3.9 or later.
- Low install friction—pure Python wheel with no runtime dependencies.
- Actively maintained as of June 2026 with recent release history.
License · maintenance · safety
MIT (permissive) — MIT license permits unrestricted use, modification, and distribution in commercial and private projects.
last release 2026-06-08 (67 days) · last repo commit 2026-06-08 · 118 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 3,134,411 downloads/mo, #2,734 on PyPI
Alternatives
Verify before relying
import logging
import json_log_formatter
formatter = json_log_formatter.JSONFormatter()
json_handler = logging.FileHandler(filename='/var/log/my-log.json')
json_handler.setFormatter(formatter)
logger = logging.getLogger('my_json')
logger.addHandler(json_handler)
logger.setLevel(logging.INFO)
logger.info('Sign up', extra={'referral_code': '52d6ce'})- Performance characteristics when logging at high volume or with large extra fields.
- Compatibility with alternative JSON libraries (ujson, simplejson) beyond the documented examples.
- Whether custom formatters can be subclassed without breaking changes across minor versions.
What it is and what it does
json-log-formatter wraps Python's standard logging module to emit structured JSON records instead of plain text. It integrates with the logging handler pipeline, converting log messages and extra fields into JSON objects written to files or streams. The library provides three formatter classes: JSONFormatter for minimal output, VerboseJSONFormatter to include standard LogRecord attributes (filename, level, thread info, etc.), and FlatJSONFormatter to stringify complex objects. It supports custom formatters by subclassing and allows swapping the underlying JSON library.
The package is designed for environments where logs feed into aggregation systems like Logstash or cloud logging platforms that parse and index JSON. It works with Django's logging configuration and requires no external dependencies beyond Python 3.9+, making it lightweight to add to existing projects.
Use it for
- Integrate application logs with Logstash or Elasticsearch for centralized log analysis and monitoring.
- Add structured metadata (user IDs, request IDs, custom fields) to logs for easier filtering and debugging in production.
- Replace plain-text logging with JSON to enable automated parsing and alerting in log aggregation pipelines.
- Configure Django applications to emit JSON logs for cloud logging services that expect structured input.
- Extend logging with custom fields and transformations by subclassing JSONFormatter for domain-specific requirements.
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes.
The package is lightweight, dependency-free, actively maintained, and solves a concrete problem—structured JSON logging is now standard practice for production systems. Install it if you're already using Python's logging module and need JSON output for log aggregation or cloud platforms.
Install
json-log-formatter on PyPI
Before you install
Low install friction—pure Python wheel with no runtime dependencies. Actively maintained as of June 2026 with recent release history.
Requires Python 3.9 or later.
License in practice
MIT license permits unrestricted use, modification, and distribution in commercial and private projects.
Quickstart
import logging
import json_log_formatter
formatter = json_log_formatter.JSONFormatter()
json_handler = logging.FileHandler(filename='/var/log/my-log.json')
json_handler.setFormatter(formatter)
logger = logging.getLogger('my_json')
logger.addHandler(json_handler)
logger.setLevel(logging.INFO)
logger.info('Sign up', extra={'referral_code': '52d6ce'})Verify before relying
- Performance characteristics when logging at high volume or with large extra fields.
- Compatibility with alternative JSON libraries (ujson, simplejson) beyond the documented examples.
- Whether custom formatters can be subclassed without breaking changes across minor versions.
Package facts
| License | MIT permissive |
| Python support | Supports the current Python release >=3.9 |
| Install friction | Low. Pure-Python wheel |
| Runtime dependencies | None |
| Maintenance | Actively maintained 67 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 3,134,411 / month, #2,734 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Intended Audience :: DevelopersLicense :: OSI Approved :: MIT LicenseOperating System :: OS IndependentProgramming Language :: PythonProgramming Language :: Python :: 3Topic :: Software Development :: Libraries :: Python Modules |
Evidence: json_log_formatter-1.2.1-py3-none-any.whl
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See also logstash_formatter · mo-logs · python-json-logger · jsonformatter · logging-json · logzero · python-logstash · json-logging · logdna · daiquiri