1) You can develop commercial software with lazarus.
2) You can also develop plugins/add-ons to the IDE and they can be commercial.
Info below given to the best of my abilities. Typos, etc can happen => so check for yourself in the license info /readme/ ... files delivered with Lazarus/FPC.
Referred general licenses are also available in the distros and online and can/should be checked.
Both above statement applies to projects/... that use
- RTL
- LCL / LclBase / LazUtils
- IdeIntf / BuildIntf
Those above package are licensed "LGPLv2 with an additional permission to link with other licenses too" (if the other license gives you the rights you need).
If you use other packages (from components folder, or other folders, or opm, or...) then you need to check each of those package.
Many, but not all packages coming with Lazarus have the "LGPLv2 with linking exception" and allow for commercial use too.
Any source/unit/package in the folder ide or any subfolder of the ide (and also iirc the top-level folders debugger and packager) are GPL. They are b]not[/b] allowed to be used in commercial software.
However, as I (and please again check for yourself / I am neither a layer nor native English speaker) have been given to understand by others and by my own reading of the GPL:
Any user can on their PC build the IDE and link a commercial plugin into it.
- However, no one can distribute a prebuild IDE with commercial packages linked in.
- The commercial plugin (e.g. pre-compiled ppu/o files), must be distributed separately from the IDE. (Or in such way that the GPL accepts it as separate)