Simplicity Scales

Abstract

The dominant data interchange formats encode integers using a variable number of bytes or represent floating-point numbers as variable-length UTF-8 strings. The decoder must inspect each byte for a continuation bit or parse each character individually, producing data-dependent branches that stall modern CPU pipelines. Protocol Buffers pays this cost on every integer, field tag, and length prefix. JSON pays it on every value. We present Bebop, a serialization format where every data type uses a fixed number of bytes. A 32-bit integer is always four bytes. Decoding becomes a single memory read with no conditionals. Across 19 decode workloads, Bebop decodes 9--213$\times$ faster than Protocol Buffers. On a 1536-dimension embedding vector, Bebop decodes in 2.8 nanoseconds versus 111 nanoseconds for Protocol Buffers and 4.69 microseconds for simdjson, a 1,675$\times$ gap. On records above 64 KB, the decoder achieves 86% of peak memory bandwidth. The CPU is no longer the bottleneck. We also present a transport-agnostic RPC protocol built on the same wire format. The protocol introduces batch pipelining, where dependent cross-service calls execute in a single round trip with server-side dependency resolution. It deploys over HTTP/1.1, HTTP/2, and binary transports without proxies, removing the HTTP/2 requirement that limits gRPC on serverless platforms and in browsers.