speedtest-cli

Know your speed. Understand your connection.

speedtest-cli is a terminal network lab for measuring the connection you actually use—not just a headline Mbps number. It shows throughput, latency under load, jitter, bufferbloat, DNS behavior, stability, and local network performance in one keyboard-friendly tool.

Install  •  First test  •  Commands  •  License  •  User guide

_{Current development UI, captured from the application's renderer with illustrative test data. These are not measured connection speeds; published releases may differ.}

Most speed tests stop at download and upload. speedtest-cli helps answer the questions that matter when a video call stutters, a game lags, or Wi-Fi feels slow:

• Is the connection fast and responsive? Measure download, upload, idle and loaded latency, jitter, bufferbloat, and a quality score with workload grades.
• Where is the bottleneck? Compare Internet backends, inspect Wi-Fi, or test directly between two machines on your LAN.
• Did something change? Save results locally, browse history, pin a baseline, compare runs, and use offline statistics and insights to spot trends.
• Is the network reliable? Inspect DNS, benchmark UDP, DoH, DoT, or DoQ, monitor repeated runs, and measure ICMP response loss separately.
• Do I need a script? Use plain text, JSON, or CSV output with stable field names and units.

Prebuilt archives are the easiest option. Rust is not required to run one.

Every release also includes a matching .sha256 checksum. Extract the archive and run speedtest (speedtest.exe on Windows).

Invoke-WebRequest -Uri "https://github.com/cmdr-chara/speedtest-cli/releases/latest/download/speedtest-windows-x86_64.zip" -OutFile speedtest.zip
Expand-Archive .\speedtest.zip -DestinationPath . -Force
.\speedtest-windows-x86_64\speedtest.exe

curl -L "https://github.com/cmdr-chara/speedtest-cli/releases/latest/download/speedtest-linux-x86_64.tar.gz" -o speedtest.tar.gz
tar -xzf speedtest.tar.gz
sudo install -m 0755 speedtest-linux-x86_64/speedtest /usr/local/bin/speedtest
speedtest

case "$(uname -m)" in
  arm64) ASSET="aarch64" ;;
  x86_64) ASSET="x86_64" ;;
  *) echo "Unsupported architecture: $(uname -m)"; exit 1 ;;
esac

curl -L "https://github.com/cmdr-chara/speedtest-cli/releases/latest/download/speedtest-macos-${ASSET}.tar.gz" -o speedtest.tar.gz
tar -xzf speedtest.tar.gz
sudo install -m 0755 "speedtest-macos-${ASSET}/speedtest" /usr/local/bin/speedtest
speedtest

Building requires the current stable Rust toolchain:

git clone https://github.com/cmdr-chara/speedtest-cli.git
cd speedtest-cli
cargo build --release --locked --bin speedtest
./target/release/speedtest

See CONTRIBUTING.md for development and verification instructions.

speedtest                         # Open the interactive dashboard
speedtest --run                   # Start a test immediately
speedtest --plain                 # Human-readable terminal output
speedtest --json --no-save         # JSON output without writing history
speedtest --jsonl --no-save        # Live newline-delimited JSON events

The dashboard is safe to open and browse offline. Network activity starts only when you explicitly start a test or diagnostic. Completed tests are saved locally by default; add --no-save when you do not want to write a result.

For the interactive dashboard, use a terminal at least 80 × 24 characters:

1. Choose Run Speed Test.
2. Review the backend, duration, and stream settings.
3. Start the test and watch throughput and latency under load.
4. Open History to revisit a result or compare it with a baseline.

Full keyboard guide and cockpit behavior →

speedtest insights, history browsing, monitor reports, and the dashboard itself do not need a network connection. They read local data only.

The live view shows throughput alongside latency as the test progresses.

Browse saved tests, pin a baseline, compare it with another run, and open the full result.

All gallery images use deterministic fixtures rendered by the current application. Capture details →

Export a result, then check it offline against your own thresholds:

speedtest --json --no-save > result.json
speedtest check result.json --min-download 100 --min-upload 20 --max-latency 30

A passing check exits 0. A failed threshold exits 3. CSV is also available:

speedtest --output result.csv --format csv

Machine-readable output keeps canonical field names, units, command names, and provider identifiers regardless of interface language. Read the automation contract, offline checks, and storage guarantees for output streams, errors, cancellation, and concurrent jobs.

• Local history: results are stored locally and can be disabled per run with --no-save.
• Explicit network work: opening the dashboard, changing sections, reading history, and running insights do not contact a server.
• LAN mode: the LAN server is unauthenticated and unencrypted. Bind it only on a trusted network; never expose it to the Internet.
• DNS changes: inspection and benchmarks are read-only. Commands such as dns set and dns optimize change system settings—preview them with --dry-run first and read the DNS guide.
• Interpretation: quality grades are local heuristics, not certifications. HTTP availability and ICMP loss measure different things.
• Guided diagnostics: diagnose contacts the configured diagnostic, stability, speed-test, and handshake endpoints. It is explicit network work; use --no-stability or --no-speedtest to narrow the run.
• Protocol probes: HTTP/2, HTTP/3, DoT, and DoQ results depend on endpoint support, firewall policy, routing, and local resolver behavior. An unavailable optional protocol is evidence about that path, not proof that every service is unavailable.
• Project status: this is an independent project, not an official Cloudflare or LibreSpeed client.

The interface supports English, Italian, Spanish, French, German, Portuguese, Simplified Chinese, and Japanese. Choose a language in Settings → Language or start with, for example, speedtest --language it.

Choose Terminal (adaptive), Graphite, Light, or Monochrome palettes, plus Comfortable or Compact layouts. The interface reflows with the terminal window; use your terminal's own font-size controls to enlarge text.

Language and readability guide →

• User guide — installation, commands, keyboard controls, DNS, result semantics, and storage.
• Network cockpit architecture — state, services, and rendering.
• Verification reports — recorded checks and known limitations.
• Contributing — build, test, and contribution workflow.
• Report an issue — include the command, platform, and relevant output.

The current repository is distributed under the speedtest-cli Source Available License 1.0. Here is the short version:

• You may use, study, modify, and share the software without a fee.
• Personal, educational, research, and internal business use are allowed.
• If you distribute the software or a modified version, you must provide the complete corresponding source under the same terms and preserve the required notices.
• If you run a modified version for people over a network, you must offer those users the corresponding source for free while that version is operated.
• You may not sell it, bundle it into a paid product, or provide a paid remote diagnostic or measurement service using it without separate written permission.
• Private, undistributed modifications do not require source disclosure.
• Material that was previously released under MIT—including the published v0.6.0 release—keeps its MIT permissions. See the historical MIT notice in LICENSE.

This is a custom source-available license. It is not the AGPL and is not an OSI-approved open-source license. The bullets above are only a convenience summary; the full license text controls. For commercial permission, open an issue without including confidential or personal information.