serialize_precision¶
The serialize_precision PHP ini directive controls the number of significant digits used when serializing float values via serialize() and json_encode().
Since PHP 7.1, the default is -1, which uses the minimum number of digits needed to uniquely represent each float (G format), ensuring round-trip fidelity. A positive integer value uses that many significant digits instead, which may introduce rounding.
<?php
// With serialize_precision = -1 (default since PHP 7.1)
$value = 3.141592653589793;
echo json_encode($value);
// outputs: 3.141592653589793
// With serialize_precision = 14
// outputs: 3.1415926535898
?>
See also serialize_precision directive and precision.
Related : Directives, Floating Point Numbers, precision, Serialization, SplSubject
