Memcached is simple yet powerful. Its simple design promotes quick deployment, ease of development, and solves many problems facing large data caches. Its API is available for most popular languages.
echo "stats" | nc localhost 11211
memcached -vv
echo "stats slabs" | nc localhost 11211
echo "stats items" | nc localhost 11211
echo "stats sizes" | nc localhost 11211
echo "flush_all" | nc localhost 11211
stats cachedump <slabs_id> <limit>
echo "stats cachedump 1 0" | nc localhost 11211
echo "get key1 key2" | nc localhost 11211