jansson is a pretty fast json encoder/decoder written in C: https://github.com/akheron/jansson
<?php $start = microtime(true); for ($i=0; $i<10000; $i++) { $enc = json_encode($_SERVER); } printf("json_encode: %s\n", microtime(true)-$start); $legacy = $enc; $start = microtime(true); for ($i=0; $i<10000; $i++) { $enc = jsson_encode($_SERVER); } $new = $enc; printf("jsson_encode: %s\n", microtime(true)-$start); $start = microtime(true); for ($i=0; $i<10000; $i++) { json_decode($legacy); } printf("json_decode: %s\n", microtime(true)-$start); $start = microtime(true); for ($i=0; $i<10000; $i++) { jsson_decode($new); } printf("jsson_decode: %s\n", microtime(true)-$start); ?>json_encode: 1.1663799285889 jsson_encode: 0.96577715873718 json_decode: 2.0289180278778 jsson_decode: 1.673702955246 phpize ./configure --with-jansson=/usr make install string jsson_encode(mixed $variable); mixed jsson_decode(string $json); Note: there is an extra 's' in the function names to avoid clashing