speedtest-cli — Test Network Bandwidth from the Command Line

Introduction

speedtest-cli is a command-line interface for testing internet bandwidth using Ookla's Speedtest.net infrastructure. It lets developers and ops teams measure network performance from servers, containers, or CI pipelines without opening a browser.

What speedtest-cli Does

• Measures download and upload throughput against the nearest Speedtest server
• Reports latency (ping) to the selected test server
• Outputs results in plain text, CSV, or JSON for scripted consumption
• Lets you pick a specific server by ID or list available servers by distance
• Supports simple and share-image output modes

Architecture Overview

speedtest-cli is a single-file Python script that communicates with the Speedtest.net HTTP API. It fetches a server list ranked by geographic distance, selects the best candidate based on latency, then performs multi-threaded download and upload transfers to calculate throughput. Results are computed locally and printed to stdout.

Self-Hosting & Configuration

• Install via pip, pipx, or your distro package manager
• No configuration files needed; all options are passed as CLI flags
• Use --server to pin a specific Speedtest server ID for consistent benchmarks
• Integrate into monitoring with --json piped to a time-series database
• Works on Linux, macOS, Windows, and inside Docker containers

Key Features

• Zero-config instant bandwidth test from any terminal
• JSON and CSV output for integration with dashboards and alerting
• Server selection by ID, country, or automatic nearest-server detection
• Lightweight single-file script with no compiled dependencies
• Widely used as a baseline network diagnostic in DevOps runbooks

Comparison with Similar Tools

• Ookla Speedtest CLI — official binary from Ookla; speedtest-cli is the community Python alternative
• fast-cli — tests against Netflix Fast.com; speedtest-cli uses the Ookla network
• iperf3 — measures raw TCP/UDP between two endpoints you control; speedtest-cli tests internet bandwidth
• LibreSpeed — self-hosted speed test; speedtest-cli relies on public Ookla servers
• mtr — focuses on route-level latency and packet loss; speedtest-cli measures throughput

FAQ

Q: Is speedtest-cli the same as the official Ookla Speedtest CLI? A: No. speedtest-cli is a community open-source Python project. Ookla later released their own closed-source binary with the same name concept.

Q: Can I run it in a cron job for continuous monitoring? A: Yes. Use --json and pipe results into InfluxDB, Prometheus Pushgateway, or a log file for trend analysis.

Q: How accurate are the results compared to the browser test? A: Results are generally comparable. Differences may arise from thread count, server selection, and network conditions during the test window.

Q: Does it support IPv6? A: The tool defaults to the system's preferred IP version. Some Speedtest servers support IPv6 depending on their configuration.

Sources

• https://github.com/sivel/speedtest-cli
• https://pypi.org/project/speedtest-cli/