We open-sourced libssz, a fast, no_std SSZ library in Rust. It's available on http:/crates.io. EL clients are picking up SSZ. In ethrex we keep dependencies minimal and care a lot about performance, so we built our own: fast for binary SSZ transport, fast and zkVM-friendly for EIP-8025 proving. Faster than Lighthouse on encode and decode. Passes 62,489 consensus spec tests across all forks. Multiple differential fuzz targets against Lighthouse and ssz_rs are running nightly. Pluggable SHA-256 backend so zkVM vendors can use their own accelerators. We're already using it in @ethrex_client and @ethlambda_lean. ere-guests switched and measured a 2x hash_tree_root speedup inside ziskemu. Compiles on RISC-V and thumbv7m out of the box.