---
id: orderedmultidict
version: "1.0.2"
license: Unlicense
license_treatment: permissive
maintenance: aging
---

# orderedmultidict — Ordered Multivalue Dictionary

License: permissive · Maintenance: aging · Downloads: 6.0M/mo

## What it is and what it does

orderedmultidict (omdict) is a dictionary implementation that allows multiple values to be stored under a single key, while maintaining the order in which keys and values were inserted or modified. It provides method parity with Python's built-in dict, so it can often be used as a drop-in replacement. The package depends only on six and is written in pure Python, making it lightweight and portable.

The primary use case is handling data structures where a key naturally maps to multiple values—such as URL query parameters or form submissions—while preserving the sequence of insertions. It supports standard dict operations like update(), get(), and items(), alongside multidict-specific methods like add(), addlist(), and getlist() for managing multiple values per key.

Use it for:

- Parse and manipulate URL query strings where parameters may repeat (used by furl)
- Store form submission data where a field name may have multiple values
- Build ordered key-value stores that need to preserve insertion sequence across updates
- Replace dict in code that needs multivalue semantics without rewriting the API

## Worth the install?

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

orderedmultidict provides a dictionary that stores multiple values per key while preserving insertion order, with an API compatible with Python's built-in dict.

Yes, if you need multivalue dictionary semantics. The package is stable, has no known vulnerabilities, installs with low friction, and is in the public domain. The 269-day maintenance gap is a minor concern for a mature library, but the active repository and broad Python version support (2.7, 3.6–3.9, PyPy) make it reliable for existing projects. Not necessary if you can use a list-of-tuples or a dict-of-lists instead.

## Install

pip install orderedmultidict
uv add orderedmultidict
poetry add orderedmultidict

## Installing orderedmultidict

Before you install: Installation is straightforward with low friction; the package depends only on six and ships as a pure Python wheel. Maintenance is aging—no releases in 269 days—but the repository remains active and the codebase is stable.

License in practice: Released under the Unlicense and placed in the public domain, so there are no licensing restrictions on use, modification, or redistribution.

Quickstart:

pip install orderedmultidict

from orderedmultidict import omdict
omd = omdict()
omd.add(1, 'first')
omd.add(1, 'second')
print(omd.getlist(1))  # [1, 'first', 'second']

Verify before relying:

- Current compatibility with Python versions beyond 3.9 (classifiers list 3.9 as the highest)
- Whether the package is actively maintained or in maintenance-only mode given the 269-day gap since last release

## Package facts

- License: Unlicense (permissive)
- Python support: unspecified
- Install friction: low
- Maintenance: aging
- Downloads: 6.0M/month (top 5,000 on PyPI)
- Known vulnerabilities: none known

## Tags

multivalue dictionary, ordered multidict, multiple values per key, dict with multiple values, ordered key-value storage, multidict python, preserve insertion order dict, data-structure, dict-replacement

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