speedtest-cli

Multi-stream internet speed test with bufferbloat + watch mode

v1.1.1

Linux

Quick Start

Install

curl -fsSL https://cli.johlem.net/install.sh | bash -s -- speedtest-cli

Uninstall

curl -fsSL https://cli.johlem.net/uninstall.sh | bash -s -- speedtest-cli

NixOS / Nix

nix profile install "tarball+https://cli.johlem.net/releases/cli-johlem-net-latest.tar.gz#speedtest-cli"

Features

Multi-stream bandwidth: spawns N parallel HTTP transfers (default 4); single-stream measurements under-report on long-fat-pipe links
Bufferbloat metric: samples latency *during* the load test and reports `loaded - idle` with a DSLReports-style A..F grade — the metric that correlates with video-call quality
Idle ping: min / max / avg / jitter / p95 over a configurable sample count
`--watch <secs>`: repeat-on-interval mode, appends one CSV row per run to `~/.local/share/speedtest-cli/history.csv`
Per-stream throughput breakdowns in JSON output
`--download-only` / `--upload-only` to limit which leg runs
`--ping-only` for a quick health check (no bandwidth load)
ISP, location, external IP detection via ip-api.com (best-effort)
Transfer-time ETA table for seven common file sizes
`--json` machine-readable output with bps + Mbps + per-stream + p95
`--no-color` for clean log capture; ANSI colours by default
Hardened defaults: minimum `--watch` interval of 30 s; max 16 streams
Zero runtime dependencies — single static binary

Requirements

Runtime

Linux x86_64 (zero runtime deps)

Dependencies

Zero third-party dependencies — Python standard library only.

Network

Outbound HTTPS access to speed.cloudflare.com (primary) and download.thinkbroadband.com (fallback). ISP/geo lookups use ip-api.com and api.ipify.org but are non-fatal if blocked.

Usage

speedtest-cli [OPTIONS]

Run speedtest-cli --help to see every flag.

Flags

Flag	Purpose
`--download-only`	Only run the download leg of the test
`--upload-only`	Only run the upload leg of the test
`--quick`	Fast single-sample test (less accurate, no warm-up)
`--size SIZE`	Custom size for ETA estimation (e.g. `1GB`, `500MB`, `2.5GB`)
`--no-color`	Disable ANSI colour output
`--json`	Output final results as JSON (suppresses live progress)
`--server URL`	Custom download test URL (must accept `?bytes=N`)
`--version`	Print the version banner

Examples

Full speed test

$ speedtest-cli

  ╔══════════════════════════════════════════════════════╗
  ║   speedtest-cli  v1.0.0  —  CLI Internet Speed Test  ║
  ╚══════════════════════════════════════════════════════╝

  ── Network Info ────────────────────────────────────────
  External IP: 203.0.113.42  Local: 192.168.1.50
  ISP: Example Telecom — Luxembourg, LU

  ── Ping / Latency ──────────────────────────────────────
  Ping: 14.2 ms avg  jitter 1.8 ms

  ── Download ────────────────────────────────────────────
  Result: 487.31 Mbps  ✓  Very Good

  ── Upload ──────────────────────────────────────────────
  Result: 92.18 Mbps  ◎  Good

Fast single-sample test

$ speedtest-cli --quick

Estimate transfer time for a custom size

$ speedtest-cli --size 2.5GB
  ...
  ─── Custom Size: 2.5 GB ─────────────────────────────
  Download: 42s
  Upload:   3m 38s

JSON output for scripting

$ speedtest-cli --json
{
  "timestamp":    "2026-05-26T15:42:11",
  "external_ip":  "203.0.113.42",
  "isp":          "Example Telecom",
  "ping_ms":      { "avg": 14.2, "jitter": 1.8 },
  "download_mbps": 487.31,
  "upload_mbps":   92.18
}

Download only, no colour, log-friendly

$ speedtest-cli --download-only --no-color >> speedtest.log

Install Layout

# Standard layout for all cli.johlem.net tools
~/.local/lib/speedtest-cli/                       # Tool source files
~/.local/bin/speedtest-cli                        # Executable wrapper
~/.local/log/cli.johlem.net/speedtest-cli_*.log   # Install/uninstall logs

After install, run speedtest-cli --help (requires ~/.local/bin in your PATH).

Changelog

# Changelog

All notable changes to `speedtest-cli` (Rust). Format: [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).

## [1.1.0] — 2026-06-06

Release notes pending — fill in before announcing.

## [1.0.0] — 2026-06-05

Initial Rust release.

Integrity

Verify your download against these SHA256 checksums:

File	SHA256

This tool is provided as-is with no warranty. Use at your own risk. Always review scripts before running them. Not responsible for any damage or data loss. Intended for authorized network diagnostics, research, and educational purposes only.