{"id":9204,"date":"2025-05-07T05:14:00","date_gmt":"2025-05-07T03:14:00","guid":{"rendered":"https:\/\/tajdini.net\/blog\/?p=9204"},"modified":"2025-12-11T04:56:18","modified_gmt":"2025-12-11T02:56:18","slug":"comparative-analysis-of-open-source-licenses-and-their-impact-on-proprietary-software-development","status":"publish","type":"post","link":"https:\/\/tajdini.net\/blog\/application-and-software-security\/comparative-analysis-of-open-source-licenses-and-their-impact-on-proprietary-software-development\/","title":{"rendered":"Comparative Analysis of Open-Source Licenses and Their Impact on Proprietary Software Development"},"content":{"rendered":"\n

Introduction<\/strong><\/h2>\n\n\n\n

Open-source software (OSS) licenses define how code can be used, modified, redistributed, or integrated into other software systems. While many licenses allow developers to freely incorporate open-source components into proprietary applications, others impose strong copyleft obligations<\/strong> that may legally require organizations to disclose their own source code if they integrate the licensed components.<\/p>\n\n\n\n

This article compares the major OSS license families GPL, AGPL, LGPL, SSPL, MPL, Apache, MIT, BSD<\/strong> with a focus on how they impact commercial, closed-source development<\/strong>.<\/p>\n\n\n\n

1. Understanding Copyleft vs. Permissive Licensing<\/strong><\/h1>\n\n\n\n

Permissive Licenses<\/strong><\/h3>\n\n\n\n

Permissive licenses (MIT, BSD, Apache) allow almost unrestricted use:<\/p>\n\n\n\n

    \n
  • Code can be copied, modified, and included in proprietary software.<\/li>\n\n\n\n
  • You are not required to open-source your own code.<\/li>\n\n\n\n
  • Only minimal obligations apply (e.g., copyright notice).<\/li>\n<\/ul>\n\n\n\n

    Zero risk<\/strong> for proprietary software.<\/p>\n\n\n\n

    Copyleft Licenses<\/strong><\/h3>\n\n\n\n

    “Copyleft” licenses impose obligations:<\/p>\n\n\n\n

      \n
    • If you modify the covered code and distribute it, you must make your modifications open-source.<\/li>\n\n\n\n
    • Stronger copyleft licenses force your entire application<\/em> to become open-source if you link them.<\/li>\n<\/ul>\n\n\n\n

      Copyleft has two categories:<\/p>\n\n\n\n

      1. Weak Copyleft<\/strong><\/h4>\n\n\n\n
        \n
      • Applies only to the modified files or components under that license.<\/li>\n\n\n\n
      • Your proprietary code can remain closed.<\/li>\n<\/ul>\n\n\n\n

        Examples: LGPL (dynamic link), MPL, EPL, CDDL<\/strong><\/p>\n\n\n\n

        2. Strong Copyleft<\/strong><\/h4>\n\n\n\n
          \n
        • Extends to any program that links, combines, or interacts with the licensed code.<\/li>\n\n\n\n
        • Your entire application may need to be open-sourced.<\/li>\n<\/ul>\n\n\n\n

          Examples: GPL, AGPL, SSPL (very strong)<\/strong><\/p>\n\n\n\n

          2. Analysis of Strong Copyleft Licenses<\/strong><\/h1>\n\n\n\n

          2.1 GPL (GNU General Public License \u2013 v2 & v3)<\/strong><\/h2>\n\n\n\n

          Key Principle<\/strong><\/h3>\n\n\n\n

          If you link GPL code (even dynamically) into your application, the entire application becomes a derivative work<\/strong>, and you must release the entire source code<\/strong> under GPL.<\/p>\n\n\n\n

          Implications for proprietary software<\/strong><\/h3>\n\n\n\n
            \n
          • GPL code cannot be used<\/strong> in commercial closed-source applications.<\/li>\n\n\n\n
          • Any distribution of GPL-linked software requires open-source disclosure.<\/li>\n\n\n\n
          • GPLv3 adds anti-tivoization and patent clauses, making it even more restrictive.<\/li>\n<\/ul>\n\n\n\n

            Strength<\/strong><\/h3>\n\n\n\n

            Strong copyleft.<\/strong><\/p>\n\n\n\n

            2.2 AGPL (Affero General Public License)<\/strong><\/h2>\n\n\n\n

            Why it is stronger than GPL<\/strong><\/h3>\n\n\n\n

            AGPL closes the “SaaS loophole”.
            Even if you NEVER distribute the software, but only run it as a hosted service<\/strong>, you must still provide full source code to users who interact with it.<\/p>\n\n\n\n

            Impact<\/strong><\/h3>\n\n\n\n

            If AGPL code runs in:<\/p>\n\n\n\n

              \n
            • A backend API<\/li>\n\n\n\n
            • A microservice<\/li>\n\n\n\n
            • An internal platform exposed to users<\/li>\n<\/ul>\n\n\n\n

              \u2192 You must open-source your modifications and often the entire stack.<\/p>\n\n\n\n

              Strength<\/strong><\/h3>\n\n\n\n

              Very strong copyleft<\/strong>, extends through the network.<\/p>\n\n\n\n

              2.3 SSPL (Server Side Public License)<\/strong><\/h2>\n\n\n\n

              MongoDB\u2019s replacement for AGPL<\/strong><\/h3>\n\n\n\n

              SSPL requires:<\/p>\n\n\n\n

                \n
              • If you use the software as a service,<\/li>\n\n\n\n
              • You must open-source not only your modifications<\/strong><\/li>\n\n\n\n
              • BUT also “the entire service stack”, including:\n
                  \n
                • Deployment scripts<\/li>\n\n\n\n
                • Orchestration tooling<\/li>\n\n\n\n
                • Monitoring code<\/li>\n\n\n\n
                • Any management software<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n

                  This makes SSPL incompatible with almost all proprietary cloud services.<\/p>\n\n\n\n

                  Strength<\/strong><\/h3>\n\n\n\n

                  Extreme copyleft<\/strong>, broader than AGPL, not OSI approved.<\/p>\n\n\n\n

                  3. Weak Copyleft Licenses<\/strong><\/h1>\n\n\n\n

                  3.1 LGPL (Lesser GPL)<\/strong><\/h2>\n\n\n\n

                  Dynamic linking allowed<\/strong><\/h3>\n\n\n\n

                  If you dynamically link to an LGPL library:<\/p>\n\n\n\n

                    \n
                  • Your code can remain closed-source.<\/li>\n\n\n\n
                  • Only modifications to the LGPL component must be disclosed.<\/li>\n<\/ul>\n\n\n\n

                    Static linking danger<\/strong><\/h3>\n\n\n\n

                    If statically linked, LGPL behaves similarly to GPL:<\/p>\n\n\n\n

                    \u2192 Your code may be considered a derivative work \u2192 forces disclosure<\/strong>.<\/p>\n\n\n\n

                    Strength<\/strong><\/h3>\n\n\n\n

                    Weak-to-medium copyleft, depending on linking.<\/p>\n\n\n\n

                    3.2 MPL (Mozilla Public License)<\/strong><\/h2>\n\n\n\n

                    File-level copyleft<\/strong><\/h3>\n\n\n\n

                    If you modify MPL-licensed files:<\/p>\n\n\n\n

                      \n
                    • Only those files (not your entire project) must remain open-source.<\/li>\n<\/ul>\n\n\n\n

                      Safe for proprietary projects<\/strong><\/h3>\n\n\n\n

                      As long as MPL files stay separate.<\/p>\n\n\n\n

                      3.3 CDDL & EPL<\/strong><\/h2>\n\n\n\n

                      Similar to MPL:<\/p>\n\n\n\n

                        \n
                      • Copyleft applies per file\/module.<\/li>\n\n\n\n
                      • Proprietary code remains proprietary.<\/li>\n<\/ul>\n\n\n\n

                        Strength<\/strong><\/h3>\n\n\n\n

                        Weak copyleft.<\/p>\n\n\n\n

                        4. Permissive Licenses (Safe for Commercial Use)<\/strong><\/h1>\n\n\n\n

                        4.1 MIT License<\/strong><\/h2>\n\n\n\n
                          \n
                        • Minimal obligations.<\/li>\n\n\n\n
                        • Allows reuse in proprietary software.<\/li>\n<\/ul>\n\n\n\n

                          4.2 Apache 2.0<\/strong><\/h2>\n\n\n\n
                            \n
                          • Patent protection included.<\/li>\n\n\n\n
                          • Safe for enterprise usage.<\/li>\n<\/ul>\n\n\n\n

                            4.3 BSD Licenses<\/strong><\/h2>\n\n\n\n
                              \n
                            • Similar permissive terms to MIT.<\/li>\n<\/ul>\n\n\n\n

                              Strength<\/strong><\/h3>\n\n\n\n

                              Zero copyleft.<\/p>\n\n\n\n

                              \n\n\n\n

                              5. High-Level Comparison Table<\/strong><\/h1>\n\n\n\n
                              License<\/th>Copyleft Strength<\/th>Requires Open-Sourcing Entire App?<\/th>SaaS Obligation?<\/th>Safe for Proprietary Use?<\/th><\/tr><\/thead>
                              GPL-2.0 \/ GPL-3.0<\/strong><\/td>Strong<\/td>Yes<\/strong><\/td>No<\/td>\u274c No<\/td><\/tr>
                              AGPL-3.0<\/strong><\/td>Very Strong<\/td>Yes<\/td>Yes<\/strong><\/td>\u274c No<\/td><\/tr>
                              SSPL<\/strong><\/td>Extreme<\/td>Yes<\/td>Yes \u2013 full service stack<\/strong><\/td>\u274c No<\/td><\/tr>
                              LGPL<\/strong><\/td>Weak\/Medium<\/td>Only if static link<\/td>No<\/td>\u26a0\ufe0f Usually<\/td><\/tr>
                              MPL-2.0<\/strong><\/td>Weak<\/td>No<\/td>No<\/td>\u2714 Yes<\/td><\/tr>
                              EPL \/ CDDL<\/strong><\/td>Weak<\/td>No<\/td>No<\/td>\u2714 Yes<\/td><\/tr>
                              MIT \/ BSD<\/strong><\/td>None<\/td>No<\/td>No<\/td>\u2714\u2714 Yes<\/td><\/tr>
                              Apache 2.0<\/strong><\/td>None<\/td>No<\/td>No<\/td>\u2714\u2714 Yes<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

                              6. Summary of Key Differences<\/strong><\/h1>\n\n\n\n

                              GPL \/ AGGPL \/ SSPL<\/strong> (strong copyleft)<\/h3>\n\n\n\n
                                \n
                              • Forces open-sourcing of your code if linked or combined.<\/li>\n\n\n\n
                              • AGPL forces disclosure for network services.<\/li>\n\n\n\n
                              • SSPL forces disclosure of entire cloud infrastructure stack.<\/li>\n<\/ul>\n\n\n\n

                                LGPL \/ MPL \/ CDDL \/ EPL<\/strong> (weak copyleft)<\/h3>\n\n\n\n
                                  \n
                                • Only modifications to the licensed files must be shared.<\/li>\n\n\n\n
                                • Your proprietary code can remain closed.<\/li>\n<\/ul>\n\n\n\n

                                  MIT \/ BSD \/ Apache<\/strong> (permissive)<\/h3>\n\n\n\n
                                    \n
                                  • No obligation to open-source your own code.<\/li>\n\n\n\n
                                  • Minimal restrictions.<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"

                                    Introduction Open-source software (OSS) licenses define how code can be used, modified, redistributed, or integrated into other software systems. While many licenses allow developers to freely […]<\/p>\n","protected":false},"author":1,"featured_media":9205,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[220],"tags":[217,261],"class_list":["post-9204","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-application-and-software-security","tag-devsecops","tag-open-source"],"_links":{"self":[{"href":"https:\/\/tajdini.net\/blog\/wp-json\/wp\/v2\/posts\/9204","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/tajdini.net\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/tajdini.net\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/tajdini.net\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/tajdini.net\/blog\/wp-json\/wp\/v2\/comments?post=9204"}],"version-history":[{"count":1,"href":"https:\/\/tajdini.net\/blog\/wp-json\/wp\/v2\/posts\/9204\/revisions"}],"predecessor-version":[{"id":9206,"href":"https:\/\/tajdini.net\/blog\/wp-json\/wp\/v2\/posts\/9204\/revisions\/9206"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/tajdini.net\/blog\/wp-json\/wp\/v2\/media\/9205"}],"wp:attachment":[{"href":"https:\/\/tajdini.net\/blog\/wp-json\/wp\/v2\/media?parent=9204"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/tajdini.net\/blog\/wp-json\/wp\/v2\/categories?post=9204"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/tajdini.net\/blog\/wp-json\/wp\/v2\/tags?post=9204"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}