glom
A declarative object transformer and formatter, for conglomerating nested data.
Decision gist · record as of 2026-08-14
Yes. glom is actively maintained, has no known vulnerabilities, installs with low friction, and solves a common real-world problem—navigating and transforming nested data—more readably than raw Python. The permissive license and wide Python version support make it safe to adopt. Use it when you're working with nested JSON, APIs, or complex object hierarchies.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Low friction: pure-Python wheel with three lightweight runtime dependencies (boltons, attrs, face).
- Active maintenance with recent releases; last commit 2026-07-17.
- Tested across Python 3.7–3.14 and PyPy3.
License · maintenance · safety
permissive license (permissive) — Permissive license (BSD) with no notable restrictions on use or redistribution.
last release 2025-12-29 (228 days) · last repo commit 2026-07-17 · 2,163 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 23,557,049 downloads/mo, #939 on PyPI
Alternatives
Verify before relying
pip install glom
from glom import glom
data = {'a': {'b': {'c': 'd'}}}
result = glom(data, 'a.b.c')
print(result) # 'd'- Performance characteristics on very large nested structures or deeply nested paths
- Whether the CLI tool (glom command) is commonly used in production workflows beyond experimentation
What it is and what it does
glom is a pure-Python library for accessing and transforming nested data structures using declarative, path-based specifications. Instead of writing chains of dictionary lookups or try-except blocks to handle missing keys, you write readable path strings or transformation specs that glom interprets. It handles the common case of real-world data—objects nested inside objects inside lists—and provides meaningful error messages when access fails, making debugging easier than raw Python dictionary operations.
The package includes both a Python API and a command-line interface. At the Python level, you define what data you want using glom's spec syntax, then call glom() with your target data. The CLI lets you experiment interactively with JSON, YAML, TOML, or Python data formats before translating your work into code. It depends on boltons, attrs, and face—all lightweight utilities—and runs on modern Python versions including PyPy.
Use it for
- Extract deeply nested values from JSON APIs without writing nested try-except blocks or checking for None at each level
- Transform and restructure complex data objects into a different shape for serialization or downstream processing
- Debug data structure problems interactively using the CLI before writing transformation code
- Build data pipelines that read from multiple sources and normalize them into a consistent schema
- Validate and safely access optional nested fields with clear error messages instead of cryptic KeyError or TypeError tracebacks
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes.
glom is actively maintained, has no known vulnerabilities, installs with low friction, and solves a common real-world problem—navigating and transforming nested data—more readably than raw Python. The permissive license and wide Python version support make it safe to adopt. Use it when you're working with nested JSON, APIs, or complex object hierarchies.
Install
glom on PyPI
Before you install
Low friction: pure-Python wheel with three lightweight runtime dependencies (boltons, attrs, face). Active maintenance with recent releases; last commit 2026-07-17. Tested across Python 3.7–3.14 and PyPy3.
License in practice
Permissive license (BSD) with no notable restrictions on use or redistribution.
Quickstart
pip install glom
from glom import glom
data = {'a': {'b': {'c': 'd'}}}
result = glom(data, 'a.b.c')
print(result) # 'd'Verify before relying
- Performance characteristics on very large nested structures or deeply nested paths
- Whether the CLI tool (glom command) is commonly used in production workflows beyond experimentation
Package facts
| License | permissive license permissive |
| Python support | Not specified |
| Install friction | Low. Pure-Python wheel |
| Runtime dependencies | 3 packagesboltonsattrsface |
| Maintenance | Actively maintained 228 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 23,557,049 / month, #939 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Development Status :: 5 - Production/StableIntended Audience :: DevelopersLicense :: OSI Approved :: BSD LicenseProgramming Language :: Python :: 3.10Programming Language :: Python :: 3.11Programming Language :: Python :: 3.12Programming Language :: Python :: 3.13Programming Language :: Python :: 3.14Programming Language :: Python :: 3.7Programming Language :: Python :: 3.8Programming Language :: Python :: 3.9Programming Language :: Python :: Implementation :: CPythonProgramming Language :: Python :: Implementation :: PyPyTopic :: Software Development :: LibrariesTopic :: Utilities |
Evidence: glom-25.12.0-py3-none-any.whl
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See also mo-dots · dpath · pathable · json-flatten · jsonschema-path · dm-tree · flatten-dict · python-toon · lenses · serpent