What corn syrup actually does
Corn syrup is an "invert" sugar syrup — its structure physically gets in the way of sucrose molecules linking back up into crystals, which is why it shows up in candy, caramel, and frosting recipes that need to stay smooth rather than turn grainy. It's also flavor-neutral and adds moisture without much sweetness of its own. A homemade sugar-and-water syrup, heated just enough to dissolve the sugar, approximates the anti-crystallization effect reasonably well for most home recipes, though it won't match corn syrup's exact viscosity or shelf stability.
Honey and golden syrup change the flavor
Both honey and golden syrup work as 1:1 swaps and share corn syrup's anti-crystallization job reasonably well, but neither is flavor-neutral the way corn syrup is — honey brings a distinct floral sweetness and browns faster in the oven, while golden syrup adds a mild, buttery caramel note. Golden syrup is the closer match of the two if you want to stay as close to corn syrup's flavor as possible; reach for honey when you don't mind (or actually want) its flavor coming through.
FAQ
Will the homemade syrup work in pecan pie or candy that needs to set firm?It's the most reliable of these three swaps for that use, but corn syrup's exact viscosity is hard to replicate exactly at home — expect a result that's very close, not identical, in set and chew.
Can I use maple syrup instead? It works flavor-wise as a 1:1 swap in everyday baking, but it's thinner than corn syrup and doesn't fight crystallization nearly as well, so it's not a reliable choice for candy-making specifically.