Is it typical when new concrete develops these kinds of surface issues after curing?

What you are seeing is likely concrete shrinkage, which is pretty normal when a fresh slab dries out, especially if the weather has been dry or if the concrete was exposed to rapid changes in temperature. The hairline cracks you mentioned are usually surface crazing, not necessarily a deep structural failure, but that doesn't make the contractor's attitude acceptable. When a contractor dismisses an obvious surface flaw as 'natural settling' without offering to come out and take a look, you should definitely take that as a red flag about their service and accountability. Experienced crews usually want to get off the job, so their immediate reluctance isn't standard professional practice. The job isn't finished until the finished product performs as expected, and that requires assessment.

To handle this, you need documentation. Take clear, well-lit photos of the cracks and their location relative to the edges. Since it’s only been a few days, the cracks are likely still settling. However, if these are widening or developing into deeper fissures, you need to pull the slab back up. Before doing that, you could look at the aggregate and see if the cracks seem to follow the large stones, which suggests it's just surface drying.

If you want professional assurance, you could hire an independent structural engineer just for a quick visual inspection and report. They can tell you definitively if the cracks are minor shrinkage or if the mix was problematic from the start. Don't let the contractor's evasiveness dictate the quality of what you just paid for.

I've seen this happen with garage floors before. If those hairline cracks are running in a bunch of diferent directions, it might not be just drying out. Sometimes the problem is with how they prepared the subgrade or the forms were set. You gotta check the edges to see if they're flexing or pulling away from the dirt beneath. Also, did the pour happen all at once? If there was a long pause between the initial mix and the backfill, you're gonna see much wider separation lines rather than these thin spider cracks.

I agree with the part about checking the subgrade and forms. When I was doing a small driveway job last year, I made sure to lay a string across the edges first to see if the forms were pulling up or if there were any major dips in the dirt. It is so easy for a crew to just rush that prep work, and they often blame 'natural settling' when the issue is poor execution from the start. The foreman sounds like he just wants the check to clear rather than standing by his work.

This is all making me nervous because I poured a small pad behind my shed last summer and got the same thin cracks within a week. I kept hosing it down with water the first few days because a neighbor said that helps it dry slower and stronger, and my cracks never got any bigger. Mine were so shallow I couldn't even catch a fingernail in them, and two years later the pad is still fine. So maybe check if you can feel the bottom of those cracks with your finger. Is there supposed to be saw cut lines in a patio to give the cracking a place to go, because mine had none and I wonder if that's part of it?

Gotta push back on the advice to pull the slab up if the cracks widen. That's a massive overreaction for a patio. Plenty of slabs develop a crack or two that grows a bit over the first year and still do thier job fine for decades. Tearing out a whole pour over widening hairlines without checking wheather it's moving at the control joint or just one shrink line is throwing money away. If the slab is sitting level and the edges aren't dropping, sealing the crack and watching it through a season or two makes way more sense than demolition.