I regularly buy fried rice from my local takeaway and I would like to recreate something similar. It is slightly redish in color (that's most likely chilli, but might not be, as it's not too hot) and tastes sweet and sour. I'm wondering what kind of ingredients they might be using to achieve this type of flavor, as the rice I make at home usually tasted pretty one dimensionally salty from the soy sauce. Could they be using something like tamarind juice, that's often used in Pad Thai recipes? What else can give fried rice a similar flavor profile?
Often there's no secret sauce that restaurants use, but plain old bog-standard sugar. I know it's boring, but there you go. They also may be using bottled sweet and sour sauce, which is also boring, but readily available in many supermarkets.
All is not lost, however, as if you want some more authentic ingredients then there are plenty of options. In my kitchen (which isn't big enough to satisfy my capacity requirements for exotic ingredients otherwise this list would be bigger) I have several ingredients which impart sweetness to Asian dishes:
Now for the sour:
Also worth mentioning is Mirin - a reduced-alcohol Sake, usually with a bit of salt added. It's used widely in Japanese cuisine. I personally don't use it much, but it's worth having in the flavor arsenal.
Thicker soy sauces typically have molasses or other sugar added, which would result in a much sweeter result. (some are thickened with starches, though).
If you're making an Indonesean style fried rice (Nasi Goreng), you'd use Ketjap Manis instead of typical soy sauce, which is almost a cross between molasses and soy sauce (with ginger and other spices, as GdD mentioned)
For those times before I had a source of Ketjap Manis, I'd fold in a few shredded carrots to add extra sweetness ... and I still typically do, as I just like mine pretty vegetable-heavy.
I would suspect they're using Shari, or "sushi rice". This is prepared with sugar (your sweet) and rice vinegar (your sour), and can easily be made at home. This beginner recipe on Just Hungry suggests the following ratio:
This is added to the rice immediately after cooking; you pour it over the top, then sort of chop-and-fold with the rice paddle to distribute evenly. To avoid damage to rice-cooker bowls, Maki also suggests doing the mixing in a metal bowl (to help the rice cool faster).
When the rice is cooked, seasoned, and cooled, it can be fried with whatever ingredients you like.