Pump
Fast but inflexible XML and JSON encoding for ruby objects.
Quick benchmark
Serializing an array of 100 random entries 1.000 times.
user system total real
Pump::Json#encode 0.600000 0.010000 0.610000 ( 0.603469)
Pump::Xml#encode 1.140000 0.020000 1.160000 ( 1.162651)
Pump::Xml#encode (optimized) 0.830000 0.020000 0.850000 ( 0.858750)
Ox 1.200000 0.010000 1.210000 ( 1.203765)
Oj 0.560000 0.000000 0.560000 ( 0.566166)
Yajl 1.490000 0.000000 1.490000 ( 1.493032)
ActiveModel#to_xml 24.110000 0.050000 24.160000 ( 24.170127)
ActiveModel#to_json 3.860000 0.010000 3.870000 ( 3.866130)