Introducing the new API for OSI Approved Licenses®

General
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Originally published at: Introducing the new API for OSI Approved Licenses® – Open Source Initiative

The Open Source Initiative (OSI) is excited to announce the availability of a new API service providing access to the canonical list of OSI Approved Licenses®. This service is fully public and free to use.

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This is great - thanks for making this happen!

As discussed starting here, it would be fantastic if this API supported literal SPDX license identifiers in the API URLs e.g. https://opensource.org/api/license/GPL-2.0. Furthermore it would be ideal if the SPDX identifier portion of these URLs was case insensitive, to align with the SPDX specification i.e. these API URLs should all resolve to the same endpoint:

  • https://opensource.org/api/license/GPL-2.0
  • https://opensource.org/api/license/gpl-2.0
  • https://opensource.org/api/license/gPl-2.0

There’s a slightly tricky corner case around some of the deprecated SPDX identifiers for FSF-published licenses that end in + (e.g. GPL-2.0+) - it would be ideal if these identifiers were supported too, so that API clients aren’t forced to upgrade these deprecated identifiers to their non-deprecated equivalents (e.g. GPL-2.0-or-later) in order to use the API.

The SPDX project has stated that they will never add any new license identifiers that end in + (they consider this to have been a historical mistake), so the set of such identifiers is fixed and small (there are 6 of them).

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Initial documentation provided by Automattic developer (Glynn Quelch) who led the project:

OpenSource Licenses API Documentation

Overview

The OpenSource Licenses API provides access to information about open source licenses approved by the Open Source Initiative (OSI). This RESTful API allows developers to retrieve license information, filter licenses by various criteria, and access detailed license metadata.

Base URL: https://opensource.org/api

Authentication

No authentication is required for this API. All endpoints are publicly accessible.

Endpoints

1. Get All Licenses

Retrieves a list of all public/published licenses.

Endpoint: GET /licenses

Description: Gets all the public/published licenses

Response: Array of license objects

Example Request:

GET https://opensource.org/api/licenses

Example Response:

[
  {
    "id": "mit",
    "name": "The MIT License",
    "spdx_id": "MIT",
    "version": "N/A",
    "submission_date": "",
    "submission_url": "",
    "submitter_name": "",
    "approved": false,
    "approval_date": "",
    "license_steward_version": "",
    "license_steward_url": "",
    "board_minutes": "",
    "stewards": [],
    "keywords": ["popular-strong-community"],
    "_links": {
      "self": {
        "href": "https://opensource.org/api/license/mit"
      },
      "html": {
        "href": "https://opensource.org/license/mit"
      },
      "collection": {
        "href": "https://opensource.org/api/licenses"
      }
    }
  }
]

2. Filter Licenses by Name

Filters licenses by name (partial match).

Endpoint: GET /licenses?name={name}

Parameters:

  • name (string): Filter licenses whose name contains the specified text

Description: Filters any license whose name contains the specified text

Example Request:

GET https://opensource.org/api/licenses?name=mit

Example Response:
Returns licenses with names containing “mit”, such as:

  • MIT No Attribution License
  • MITRE Collaborative Virtual Workspace License
  • The MIT License

3. Filter Licenses by Keywords

Filters licenses by specific keywords.

Endpoint: GET /licenses?keyword={keyword}

Parameters:

  • keyword (string): Filter licenses by keyword

Available Keywords:

  • popular-strong-community
  • international
  • special-purpose
  • non-reusable
  • superseded
  • voluntarily-retired
  • redundant-with-more-popular
  • other-miscellaneous
  • uncategorized

Example Request:

GET https://opensource.org/api/licenses?keyword=popular-strong-community

Example Response:
Returns popular licenses with strong community support, including:

  • Apache License 2.0
  • MIT License
  • GNU GPL v2/v3
  • BSD licenses
  • Mozilla Public License 2.0

4. Filter Licenses by Steward

Filters licenses by their steward organization.

Endpoint: GET /licenses?steward={steward}

Parameters:

  • steward (string): Filter licenses by steward organization

Common Stewards:

  • eclipse-foundation
  • free-software-foundation
  • mozilla-foundation
  • apache-software-foundation
  • python-software-foundation

Example Request:

GET https://opensource.org/api/licenses?steward=eclipse-foundation

Example Response:
Returns licenses stewarded by the Eclipse Foundation:

  • Eclipse Public License version 2.0
  • Eclipse Public License v1.0

5. Filter Licenses by SPDX ID

Filters licenses by their SPDX identifier with wildcard support.

Endpoint: GET /licenses?spdx={spdx_pattern}

Parameters:

  • spdx (string): Filter licenses by SPDX identifier (supports wildcards with *)

Description: Filters licenses by their SPDX identifier. Supports wildcard matching using the * character for flexible pattern matching.

Wildcard Patterns:

  • prefix* - Find licenses that start with the prefix
  • *suffix - Find licenses that end with the suffix
  • *contains* - Find licenses that contain the text anywhere
  • exact - Find licenses with exact match (no wildcards)

Example Request:

GET https://opensource.org/api/licenses?spdx=gpl*

Example Response:
Returns licenses with SPDX IDs starting with “gpl”, such as:

  • GNU General Public License version 3 (GPL-3.0-only)
  • GNU General Public License version 2 (GPL-2.0)

Additional Examples:

  • ?spdx=mit* - Find all that start with “mit”
  • ?spdx=*bsd - Find all that end in “bsd”
  • ?spdx=*apache* - Find any that contain “apache”
  • ?spdx=mit - Only an exact match for “mit”

Response Schema

License Object

Each license object contains the following fields:

Field Type Description
id string Unique identifier for the license
name string Full name of the license
spdx_id string SPDX identifier for the license
version string License version
submission_date string Date when license was submitted (YYYYMMDD format)
submission_url string URL of the original submission
submitter_name string Name of the person who submitted the license
approved boolean Whether the license is approved by OSI
approval_date string Date when license was approved (YYYYMMDD format)
license_steward_version string Version maintained by steward
license_steward_url string URL to steward’s license page
board_minutes string URL to board meeting minutes
stewards array Organizations that steward this license
keywords array Classification keywords for the license
_links object HATEOAS links for related resources

Links Object

The _links object contains:

Field Description
self.href API endpoint for this specific license
html.href Human-readable web page for this license
collection.href API endpoint for the licenses collection

HTTP Status Codes

Code Description
200 OK - Request successful
400 Bad Request - Invalid parameters
404 Not Found - Resource not found
500 Internal Server Error - Server error

Rate Limiting

No specific rate limiting information is documented. Standard usage practices apply.

Examples

Get all MIT-related licenses

curl "https://opensource.org/api/licenses?name=mit"

Get all popular licenses

curl "https://opensource.org/api/licenses?keyword=popular-strong-community"

Get all GNU licenses

curl "https://opensource.org/api/licenses?steward=free-software-foundation"

Get all GPL licenses using SPDX wildcard

curl "https://opensource.org/api/licenses?spdx=gpl*"

Get all BSD licenses using SPDX wildcard

curl "https://opensource.org/api/licenses?spdx=bsd*"

Notes

  • All responses are in JSON format
  • The API uses standard HTTP methods and status codes
  • Responses include HATEOAS links for navigation
  • Date fields use YYYYMMDD format
  • Empty fields may be represented as empty strings rather than null values
  • The approved field appears to be consistently false in the sample data, likely indicating a data formatting convention rather than actual approval status

Support

For questions or issues with the API, please reach out to us. Thanks!