I am sorry I am going to be a little vague and if you need more info I can offer it.
My supplier has offered me an API feed to use with my site. I can use all their info including stock levels.
How hard is it to import this information into my site and has anyone done it before who could give some good advice.
Apologies if the above seems a bit basic.
Not at all, you have the following methods.
1) Internal import/export
3) Custom script
4) External automation tool
Option 1) is manual and needs to have the import file mapped, 2) is semi-automated but technical, 3) is custom designed but automated so any changes need a programmer, 4) is automated and business changeable without a programmer. It comes down to how often you need to update the products, pricing, inventory, do you need to clean the data, do you need to map the data. The interesting thing about 4) is that it splits in to 3 sub-processes.
4a takes non-formatted data such as Excel and reformats it to Magento for upload, 4b is the same but maps and cleans the data via business rules (no programming), 4c is the same but stores the data in an external product manager for faster data entry but there's a serious headache with integration and sync so you only do that with 10s of content managers and data entry staff as the sync is lower effort. If there is any programming involved to load new datasets it's not 4) it's 3) no matter what the sales & marketing people spit out.
We're not developers, behavioral science (business marketing), however can pass you over to some people who have drop in solutions including SaaS for this type of thing if you don't have any luck.