I have developers, but no designer
Owning the interface
Without a designer, every screen is a developer’s best guess, and nobody is looking at the product as a whole. While I’m on the team, that’s my job. I review every screen and keep a running list of what needs fixing.
Working in your codebase
I stay on hand until what was designed is what gets built. Sometimes that’s feedback to your developers as they go. Sometimes it’s me making the changes myself, in your codebase.
Shipping pull requests
Some changes are quicker to make than to explain. For those I skip the mockup and open a pull request. For everything else, I review what the team builds before it goes out and catch the small things that slip.
Staying a sprint or a year
Some teams need a designer for one feature. Others need one for a year while they grow. I do both: a fixed piece of work, or joining the team for as long as you need. Either way, you know the price before we start.