{
  "question": "Can I use an LGPL-2.1 library in proprietary software?",
  "slug": "can-i-use-an-lgpl-2-1-library-in-proprietary-software",
  "url": "https://www.rightshold.com/answers/can-i-use-an-lgpl-2-1-library-in-proprietary-software",
  "short_answer": "Shipping a proprietary app that links the library: Yes. Shipping a modified copy of the library: Yes.",
  "framing": "LGPL-2.1 lets proprietary programs use the library, provided users can replace or relink the LGPL part and changes to the library itself stay LGPL.",
  "checks": [
    {
      "label": "Shipping a proprietary app that links the library",
      "license": "LGPL-2.1-only",
      "license_name": "GNU Lesser General Public License v2.1 only",
      "intended_use": {
        "commercial_use": true,
        "redistribution": true
      },
      "verdict": "permitted",
      "answer": "Yes",
      "findings": [
        "Every use you described is granted by LGPL 2.1, and nothing you described is prohibited."
      ],
      "duties": [
        "attribution",
        "license_notice",
        "state_changes",
        "share_alike",
        "source_disclosure"
      ],
      "curation": "curated",
      "official_text": "https://www.gnu.org/licenses/old-licenses/lgpl-2.1.html"
    },
    {
      "label": "Shipping a modified copy of the library",
      "license": "LGPL-2.1-only",
      "license_name": "GNU Lesser General Public License v2.1 only",
      "intended_use": {
        "modification": true,
        "redistribution": true
      },
      "verdict": "permitted",
      "answer": "Yes",
      "findings": [
        "Every use you described is granted by LGPL 2.1, and nothing you described is prohibited."
      ],
      "duties": [
        "attribution",
        "license_notice",
        "state_changes",
        "share_alike",
        "source_disclosure"
      ],
      "curation": "curated",
      "official_text": "https://www.gnu.org/licenses/old-licenses/lgpl-2.1.html"
    }
  ],
  "context": [
    "Dynamic linking is the usual way to meet the relinking condition; static linking needs object files or an equivalent so users can relink."
  ],
  "sources": [
    {
      "title": "GNU LGPL v2.1",
      "url": "https://www.gnu.org/licenses/old-licenses/lgpl-2.1.html"
    }
  ],
  "check_it_yourself": {
    "mcp": {
      "tool": "check_license",
      "arguments": {
        "license": "LGPL-2.1-only",
        "intended_use": {
          "commercial_use": true,
          "redistribution": true
        }
      }
    },
    "rest": "POST https://www.rightshold.com/v1/licenses/check"
  },
  "computed_from": "Rightshold license profiles at render time; not legal advice",
  "updated": "2026-10-23"
}