European Union Public Licence (EUPL)

Original Article ↗ Hacker News Discussion ↗

Official source and website confusion

  • Several commenters note the linked eupl.eu site is private, not an EU institution, despite EU flag imagery and tracking; they find this misleading.
  • People share links to the actual official sources on europa.eu / interoperable-europe, including the authentic license texts and Commission decision.
  • There is some discussion of how EU sites usually organize language versions and that this unofficial site doesn’t clearly point back to the official texts.

What EUPL is and design goals

  • It’s seen as a copyleft license modeled on GPL, closer to GPLv3 in spirit (patent language, modern EU law), but without some GPLv3 features like explicit anti‑tivoization.
  • One key goal: legal clarity and interoperability for EU institutions, with explicit reference to EU law and official translations in many EU languages.
  • Some view it as “weak copyleft” akin to MPL, optimized for mixing many components in complex, institutional or academic projects.

Comparison to GPL/AGPL and SaaS coverage

  • EUPL includes a broad definition of “distribution/communication” that many interpret as covering SaaS (network use), making it “Affero‑like.”
  • Others note it’s less explicit than AGPL, and discussion centers on whether this language reliably closes the “SaaS loophole.”
  • There is confusion over whether EUPL’s copyleft remains effective once GPL compatibility mechanisms are used.

Compatibility clause and relicensing debate

  • A major thread: EUPL’s “compatible license” mechanism lets combined works be distributed under certain other licenses (GPLv2, GPLv3, AGPL, etc.).
  • Critics argue this effectively lets others sidestep EUPL’s stronger conditions (e.g., SaaS obligations) by moving to GPL‑only, weakening copyleft.
  • Supporters cite EU guidance claiming the SaaS obligations persist for derivatives, but many find this legally unclear or contradictory with GPL’s “no further restrictions” rule.
  • Some characterize EUPL as more of a political/legal compromise than a “pure” strong copyleft license.

Jurisdiction, EU legal context, and “viral” effects

  • Explicit EU jurisdiction is welcomed by some (clear case law, predictable interpretation) and seen as off‑putting by others outside the EU.
  • Commenters note EU copyright and interoperability rules differ from US assumptions: linking and APIs often don’t trigger “viral” effects the way FSF rhetoric suggests.
  • EUPL’s documentation explicitly frames itself as non‑viral and stresses that simple linking does not change other components’ licenses.

Adoption and real‑world use

  • Commenters report relatively limited adoption: some EU/government releases, scattered packages in major distros, and a few notable projects.
  • One project uses a modified EUPL, which others criticize as bad practice that breaks compatibility and reintroduces issues the author wanted to avoid.
  • Some say they’d only choose EUPL when required by government clients; otherwise they prefer GPL/AGPL.

Clarity, messaging, and site presentation

  • Several people find the eupl.eu page unclear: it takes a while before it even states that EUPL is a software license.
  • Others appreciate that official EU documentation (elsewhere) is more direct and provides detailed compatibility matrices and “how to use” guides.

Broader ideological and policy debates

  • There is recurring argument over whether the EU is “late” and redundant versus providing valuable structure (similar to phone‑charger standardization debates).
  • Some want even stricter copyleft for cloud‑era fairness; others think open‑source enforcement is mostly social, not legal.
  • A side discussion emerges about “ethical” licenses (anti‑weapons, anti‑fossil‑fuel), with the reminder that such field‑of‑use restrictions are incompatible with FSF/OSI definitions and create supply‑chain risk.