There are two good reasons to have software written rather than bought, and a great many bad ones.
The first good reason is that nothing on the market fits. The second is that the thing you do differently from everyone else is precisely the thing you cannot afford to do the way everyone else does it. If neither applies, buy. If one of them does, the work should be done properly, and once.
What the work involves
- Scope in writing. What is being built, and what is explicitly not, agreed before anyone opens an editor.
- Senior hands. The people who scoped the work are the people who write it.
- Tests that mean something. Coverage of the behaviour the business depends on, rather than a percentage pursued for its own sake.
- Documentation as we go. Written while the reasoning is still fresh, not reconstructed at the end from memory.
- Deployment you control. Running in your accounts, under your keys, from the first deployment onward.
- Handover. A working system, the understanding to run it, and someone on your side who has already done so while we watched.
Every engagement ends with you owning the system outright: the code, the keys, and the understanding to run it.
What you own at the end
Everything. The source, the infrastructure definitions, the credentials, the documentation, and the intellectual property. There is no runtime licence, no hosted component you must keep renting from us, and no part of the system that only we can service.
That is a constraint on how we build rather than a courtesy extended at the end. A system only its author can maintain has been mis-built, whoever the author is.