Plumbrs is a high-performance HTTP/HTTP2 request generator designed for benchmarking servers and comparing Rust HTTP client libraries. Built on Tokio, it helps you measure throughput, latency, and identify bottlenecks.
- Auto (
auto) — Automatically select the best client (default). - Hyper (
hyper) — Hyper-based HTTP client (one per connection). - Hyper multichunk (
hyper-multichunk) — Hyper client with multi-chunked body (one per connection). - Hyper legacy (
hyper-legacy) — Legacy Hyper HTTP client (one per connection). - Hyper RT1 (
hyper-rt1) — Legacy Hyper HTTP client shared across a runtime. - Hyper H2 (
hyper-h2) — HTTP/2 client using Hyper with the h2 library (one per connection). - Reqwest (
reqwest) — Popular Reqwest HTTP client (one per runtime). - IoUring (
io-uring) — HTTP client using io_uring for high-performance I/O (Linux only). - Help (
help) — Print available client types and exit.
-
<URI>— HTTP URI(s) for the request (e.g.,http://192.168.0.1:80). Required for most clients. -
-t, --threads <NUMBER>(default:1) — Number of worker threads. -
-m, --multi-threaded <NUMBER>— Threads per Tokio runtime. If omitted, uses single-threaded executor. When specified,--threadsmust be an exact multiple of this value. -
-c, --concurrency <NUMBER>(default:1) — Concurrent connections or HTTP/2 streams. -
-d, --duration <SECONDS>— Test duration in seconds. -
-r, --requests <NUMBER>— Maximum requests per worker. If omitted, runs until duration elapses. -
-C, --client <TYPE>(default:auto) — Client type:auto,hyper,hyper-multichunk,hyper-h2,hyper-legacy,hyper-rt1,reqwest,io-uring, orhelp. -
--cps— Open a new connection for every request, measuring Connections Per Second. -
--latency— Enable latency estimation using Gil Tene's coordinated omission correction algorithm. -
--sse— Enable Server-Sent Events (SSE) handshake. Only available withautoorhyperclient. -
--host <HOST>— Override the host to connect to. Not available withhyper-legacyorhyper-rt1. -
--port <PORT>— Override the port to connect to. -
-v, --verbose— Enable verbose output. -
--metrics— Display Tokio runtime metrics at the end.
-
-M, --method <METHOD>— HTTP method (e.g.,GET,POST,PUT,DELETE). If omitted, defaults toGETwhen no body is provided, orPOSTwhen a body is specified. Note:TRACEmethod cannot have a body. -
-H, --header <KEY:VALUE>— Add HTTP header (repeatable). -
-T, --trailer <KEY:VALUE>— Add HTTP trailer (repeatable). Not available withreqwestclient. -
-B, --body <BODY>— Request body content. Can be specified multiple times for multi-chunk encoding, but multi-chunk is only supported withhyper-multichunkclient. -
-b, --body-from-file <PATH>— File path for request body (streamed). -
--http2— Use HTTP/2 only. Not available withio-uringclient.
--http1-max-buf-size <NUMBER>— Maximum buffer size (default: ~400kb).--http1-read-buf-exact-size <NUMBER>— Exact read buffer size (unsets max-buf-size).--http1-writev <true|false>— Use vectored writes (default: auto).--http1-title-case-headers— Write header names as title case.--http1-preserve-header-case— Preserve original header case. Not available withhyper-legacyorhyper-rt1.--http1-max-headers <NUMBER>— Maximum number of headers (default: 100).--http1-allow-spaces-after-header-name-in-responses— Accept spaces after header names.--http1-allow-obsolete-multiline-headers-in-responses— Accept obsolete line folding.--http1-ignore-invalid-headers-in-responses— Silently ignore malformed headers.--http09-responses— Tolerate HTTP/0.9 responses.
--http2-adaptive-window <true|false>— Enable adaptive flow control. Not available withhyper-h2.--http2-initial-max-send-streams <NUMBER>— Initial max locally initiated streams. Not available withreqwest.--http2-max-concurrent-reset-streams <NUMBER>— Max concurrently reset streams. Not available withreqwest.--http2-initial-stream-window-size <NUMBER>— Initial stream-level flow control window.--http2-initial-connection-window-size <NUMBER>— Initial connection-level flow control window.--http2-max-frame-size <NUMBER>— Maximum frame size.--http2-max-header-list-size <NUMBER>— Maximum header list size.--http2-max-send-buffer-size <NUMBER>— Maximum send buffer size. Not available withreqwest.--http2-keep-alive-while-idle— Enable keep-alive while idle. Not available withhyper-h2.
--global-queue-interval <TICKS>— Global queue interval.--event-interval <TICKS>— Event interval.--max-io-events-per-tick <NUMBER>— Maximum I/O events per tick.--disable-lifo-slot— Disable LIFO slot heuristic (requirestokio_unstable).
The io-uring client supports HTTP/1 only and does not support multi-threaded runtimes (-m).
--uring-entries <NUMBER>(default:4096) — Size of the io_uring Submission Queue.--uring-sqpoll <MILLISECONDS>— Enable kernel-side submission polling with idle timeout.
Basic GET request with 10 concurrent connections for 30 seconds:
plumbrs -c 10 -d 30 http://localhost:8080
POST request with headers and body:
plumbrs -t 4 -c 100 -M POST \
-H "Content-Type:application/json" \
-B '{"key":"value"}' http://localhost:8080/api
POST with body from file:
plumbrs -M POST -b ./payload.json http://localhost:8080/api
HTTP/2 with flow control tuning:
plumbrs -C hyper --http2 \
--http2-initial-stream-window-size 1048576 \
--http2-initial-connection-window-size 2097152 \
-c 100 -d 30 http://localhost:8080
Connections Per Second test:
plumbrs -C hyper --cps -c 10 -r 1000 http://localhost:8080
Latency-corrected benchmarking:
plumbrs --latency -c 100 -d 30 http://localhost:8080
The io-uring client delivers 382K RPS on a single thread and scales to 1.05M RPS with 4 threads. The hyper client also performs exceptionally (198K → 724K RPS), surpassing wrk. The reqwest client maintains competitive throughput (109K → 397K RPS).
The hyper-h2 client achieves 187K RPS on a single thread and 689K RPS with 4 threads. The standard hyper client with HTTP/2 follows closely (135K → 580K RPS). All Plumbrs HTTP/2 clients outperform rewrk in this benchmark.
Some options require Tokio's unstable APIs:
RUSTFLAGS="--cfg tokio_unstable" cargo build --release