Obligations that come with free code.
WHAT LICENCES REQUIRE
Varies substantially, and must be checked.
WHAT PERMISSIVE LICENCES REQUIRE
Usually attribution, and little else.
WHAT COPYLEFT LICENCES REQUIRE
That derived work is released under the same terms.
WHY THAT MATTERS
Incorporating such code into a product you distribute may oblige you to release your own source.
WHAT AFFECTS SAAS SPECIFICALLY
Most copyleft obligations trigger on distribution, and serving software over a network is frequently not distribution.
WHAT CHANGES THAT
Certain licences written specifically to cover network use.
WHAT TO DO
Identify every dependency and its licence.
WHAT TO AUTOMATE
That scan, on every build.
WHAT TO MAINTAIN
A list of dependencies and licences, current.
WHY
Customers and investors ask for it, and assembling it later is laborious.
WHAT TO AVOID
Copying code from anywhere without checking Dependencies with no licence stated Licences you have not read
WHY NO LICENCE STATED IS A PROBLEM
Absence of a licence means no permission, not free use.
WHAT TO CONTRIBUTE BACK
Fixes, where practical.
WHY
It is fair, and it reduces the burden of maintaining private changes.
WHAT TO TAKE ADVICE ON
Anything where the obligation is unclear.
