I've reached for igbinary on nearly every PHP project I've shipped in the last decade. It's smaller and faster than PHP's native serialize(), it's stable, and it has been the obvious default for so long that reaching for it stopped being a decision. So phpser started as curiosity, not a complaint. igbinary is good. Could a serializer built specifically for cache workloads do better? I wanted two things from it. It should be fast on the shapes a cache actually holds, where a value is decoded far more often than it's encoded. And it should be safe to decode bytes from a store an attacker might reach, because unserialize() on untrusted input is one of PHP's oldest exploit primitives. igbinary gives you the speed; the safety you bolt on yourself. phpser builds in both. On the shapes that matter for caches it encodes 10 to 70% faster than igbinary and decodes 12 to 75% faster, with packed numeric data also 65% smaller on the wire. Its signed mode refuses to decode any payload that wasn't produced with yo...