prance
Resolving Swagger/OpenAPI 2.0 and 3.0.0 Parser
Decision gist · record as of 2026-08-14
Yes, if you need to parse or validate OpenAPI/Swagger specs in Python. The package is actively maintained, has low install friction, and fills a real gap in reference resolution. Clarify the MITNFA license before use in proprietary contexts. Avoid the flex backend due to deprecated dependencies with known security issues.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Requires Python 3.10 or later.
- A validation backend (openapi-spec-validator, swagger-spec-validator, or flex) must be installed separately for validation to work.
- Low friction install with a pure-wheel distribution.
License · maintenance · safety
MITNFA (unclear) — License treatment is unclear (MITNFA). Verify the actual license terms before using in proprietary or restricted-license projects.
last release 2026-07-19 (26 days) · last repo commit 2026-07-19 · 262 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 6,194,071 downloads/mo, #1,959 on PyPI
Alternatives
Verify before relying
pip install prance
from prance import ResolvingParser
parser = ResolvingParser('path/to/swagger.yaml')
spec = parser.specification # fully resolved spec as dict- Whether MITNFA license is MIT-compatible or a custom variant requiring legal review
- Whether the package works correctly with all modern Python versions (3.10–3.14) despite Beta status
- Performance characteristics when resolving large or deeply nested specifications
What it is and what it does
Prance is a parser and validator for Swagger/OpenAPI specifications that handles both local file paths and remote URLs. It extends standard JSON reference resolution to work with OpenAPI's non-URI relative file paths, which standard JSON reference libraries do not support. The package provides two main parsing modes: ResolvingParser, which follows and resolves all JSON references into a flat specification dictionary, and BaseParser, which parses without resolving references.
The package includes a command-line interface for validating specs, compiling them into fully resolved output files, and converting older Swagger 2.0 specs to OpenAPI 3.0 format via an external web service. It depends on chardet, ruamel.yaml, requests, and packaging for core functionality, and delegates actual validation to pluggable backends (openapi-spec-validator, swagger-spec-validator, or flex) that you install separately.
Use it for
- Validate and resolve Swagger/OpenAPI specs in CI/CD pipelines before deploying API services
- Parse OpenAPI specifications from files or URLs into Python dictionaries for code generation or documentation tools
- Compile multi-file API specs with external references into single resolved output files for distribution
- Convert legacy Swagger 2.0 definitions to OpenAPI 3.0 format programmatically
- Extract and flatten API specifications containing JSON references for analysis or transformation
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes, if you need to parse or validate OpenAPI/Swagger specs in Python.
The package is actively maintained, has low install friction, and fills a real gap in reference resolution. Clarify the MITNFA license before use in proprietary contexts. Avoid the flex backend due to deprecated dependencies with known security issues.
Install
prance on PyPI
Before you install
Low friction install with a pure-wheel distribution. Active maintenance as of 2026-07-19 with recent releases. Requires Python 3.10 or later. Optional validation backends (openapi-spec-validator, swagger-spec-validator, flex) must be installed separately; flex is deprecated and carries security risks in its dependencies.
Requires Python 3.10 or later. A validation backend (openapi-spec-validator, swagger-spec-validator, or flex) must be installed separately for validation to work.
License in practice
License treatment is unclear (MITNFA). Verify the actual license terms before using in proprietary or restricted-license projects.
Quickstart
pip install prance
from prance import ResolvingParser
parser = ResolvingParser('path/to/swagger.yaml')
spec = parser.specification # fully resolved spec as dictVerify before relying
- Whether MITNFA license is MIT-compatible or a custom variant requiring legal review
- Whether the package works correctly with all modern Python versions (3.10–3.14) despite Beta status
- Performance characteristics when resolving large or deeply nested specifications
Package facts
| License | MITNFA unclear |
| Python support | Supports the current Python release >=3.10 |
| Install friction | Low. Pure-Python wheel |
| Runtime dependencies | 4 packageschardetruamel.yamlrequestspackaging |
| Maintenance | Actively maintained 26 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 6,194,071 / month, #1,959 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Development Status :: 4 - BetaEnvironment :: PluginsIntended Audience :: DevelopersNatural Language :: EnglishOperating System :: OS IndependentProgramming Language :: Python :: 3Programming Language :: Python :: 3.10Programming Language :: Python :: 3.11Programming Language :: Python :: 3.12Programming Language :: Python :: 3.13Programming Language :: Python :: 3.14Topic :: Internet :: WWW/HTTPTopic :: Software Development :: Libraries :: Python Modules |
Evidence: prance-26.7.19.0-py3-none-any.whl
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See also openapi-spec-validator · swagger-spec-validator · flex · openapi3 · openapi-schema-validator · aiopenapi3 · drf-yasg · openapi-codec · referencing · sceptre-file-resolver