How do I deal with early Reapers as Zerg?

Solution 1:

Your queen alone can hold off a reaper or two. Speedlings can kill non nitro-pack reapers quite easily. Roaches can...make reapers run away at least, but if the terran player is actually microing your roaches are never getting in range, especially without roach speed which comes way too late to help here. Spine crawlers also deal with small numbers of reapers quite handily.

If it is mass nitro-pack reapers things get trickier. 3 rax - 5 rax mass reaper builds are quite popular in TvZ these days. You will need at least a second queen, if not a third. Creep spread is key for the speed boost it gives your units. You will also almost certainly need roaches. Your best bet is likely going to be the 5 roach rush, roach + creep spread to allow for expansion, defensive roaches into one base muta, or something of that sort. Spine crawlers are less useful as once they have 10 reapers they can one shot them. 6 reapers suffices to take a spine crawler down with no losses.

Solution 2:

Watch and learn ;)