autocannon is a high-performance HTTP/1.1 benchmarking tool written in Node.js, inspired by wrk and wrk2. It operates as both a CLI tool and a programmable library. The architecture is centered around a run loop that manages multiple concurrent HTTP clients, each capable of pipelining requests. Key components include a request builder that constructs raw HTTP request buffers, a pipelined request queue for handling out-of-order responses, and a histogram-based statistics engine using hdr-histogram-js with WebAssembly for efficient percentile calculations. The tool supports HTTPS, Unix sockets, multipart forms, HAR file replay, worker threads for parallel execution, rate limiting with coordinated omission correction, and extensive customization via setup functions and event hooks. The codebase is well-structured with clear separation of concerns, comprehensive test coverage, and active maintenance.
Plow is a high-performance HTTP(S) benchmarking CLI tool written in Go. It uses fasthttp for efficient HTTP client operations and provides real-time metrics including latency statistics, percentiles, histograms, and throughput. The tool supports configurable concurrency, request rate limiting, ramp-up, duration-based or request-count-based runs, and custom headers, body, TLS, and proxy settings. It outputs results to the terminal with live updating tables and also serves a web UI with interactive charts (latency, RPS, status codes, concurrency) using go-echarts. The architecture is a single binary with three main components: a requester that spawns concurrent workers, a stream-based report aggregator that computes streaming quantiles and histograms, and a printer/chart server for output. The code is well-structured, thoroughly tested, and follows Go best practices. It is not a library but a standalone application, though some internal components (e.g., the streaming stats engine and throughput interceptor) are cleanly isolated and could be reused in other projects.