Let's say Alice has Project A, which is licenced under the AGPL, and Bob has Project B, which is also licenced under AGPL.

Bob sees a function in Project A that looks very useful, and wants to copy it to Project B, citing the original source in a comment.

Can Bob do this, or is it against the terms of the AGPL?

  • Yes but be aware that you no longer will be able to relicense the combined work with a different license - which makes agpl projects often pointless.
    – eckes
    Jun 13, 2022 at 18:23
  • 8
    @eckes You say it's pointless, but that's exactly the point of the (A)GPL being a viral license: to prevent downstreams from placing your code under a more restrictive license. For many, that's what they want.
    – Cole Tobin
    Jun 13, 2022 at 19:37
  • Sure, but companies using agpl do that mostly to sell ommercial licenses to make money
    – eckes
    Jun 13, 2022 at 19:38
  • 7
    @eckes and individuals using AGPL do that mostly so companies can't sell commercial licenses to make money Jun 14, 2022 at 9:53

2 Answers 2


Put simply: yes, this is allowed. The entire point of open source software is to allow it to be re-used.

Note that the requirements are slightly more than "citing the original source in a comment", or at least the comment must have a very specific form in that it must:

  • "conspicuously and appropriately publish on each copy an appropriate copyright notice" (AGPL section 4); "an appropriate copyright notice" here means reproducing the copyright notice from the original.
  • "keep intact all notices stating that this License and any non-permissive terms added in accord with section 7 apply to the code" (section 4 again)
  • "keep intact all notices of the absence of any warranty" (section 4 again)
  • "give all recipients a copy of this License along with the Program" (section 4 again), although Bob will have been doing that anyway.
  • "The work must carry prominent notices stating that you modified it, and giving a relevant date." (section 5)

As Philip wrote: Yes, that's possible (subject to certain conditions, which I won't repeat here).

Do note, though, that this will make it harder for Bob to re-license his code with a different license in the future: As long as it's only his own code, he can distribute it under as many licenses as he wishes. For example, many projects offer both a free GPL version and, for a fee, a version without a copy-left requirement for inclusion in closed-source projects.

As soon as Bob includes AGPL'ed code written by Alice, this is no longer possible without getting permission from Alice.

  • We assume here Alice won't be fine with getting a cut from her contribution...
    – MrMesees
    Jun 14, 2022 at 19:08

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