Reddit's API documentation: https://www.reddit.com/dev/api

Description of the API's return data: https://github.com/reddit/reddit/wiki/JSON

Terminology

Reddit's API is slightly inconsistent in its naming; "id" sometimes refers to a thing's short ID, and sometimes to its fullname (the combination of its prefix and id). To avoid confusion, this guide will always refer to things in the following way:

Term	Description	Example
fullname	A thing's complete ID with prefix. The type of thing can be determined by the first two characters ("t1" for comment, "t3" for post, etc).	t1_cvp5afk
id	A thing's short ID without prefix. Seen in your address bar when viewing, for example, a post or comment. Useful for constructing URLs.	3npkj4

Listings

Methods that return lists of things can accept several optional parameters:

Parameter	Type	Description
limit	integer	How many things to return. Default 25, maximum 100. If limit is present but false, this is interpreted as "no limit" and the maximum is returned.
before	fullname	Return results that occur before fullname in the listing.
after	fullname	Return results that occur after fullname in the listing.
count	integer	Appears to be used by Reddit to number listings after the first page. Does not seem to have a use in the API.
only	"links" or "comments"	Return only links or comments.
show_all	boolean	Return items that would have been omitted, for example posts you have hidden, or were hidden because you are using the option to hide posts after you've upvoted/downvoted them. Default false.

Note that 'before' and 'after' mean before and after in the listing, not necessarily in time. It's best to think of Reddit as a database where new lines are constantly inserted at the top, because that's basically what it is.

Types of Thing

t1	Comment
t2	Account
t3	Link
t4	Message
t5	Subreddit
t6	Award
t8	PromoCampaign