Output and privacy

Output formats

Output	Flag	Use it for
Live progress	none	Watching a test in a terminal
Plain lines	`--unix`	Logs, and terminals that cannot redraw
One JSON document	`--json`	Scripts that read the whole result
One JSON line per server	`--jsonl`	Scripts that process servers one at a time

Things to know:

Use at most one of --json, --jsonl, and --unix. More than one is an invalid setting.
When the output is not a terminal, such as a pipe or a file, or with --debug, the results are plain lines without the progress, as with --unix.
With --json or --jsonl, nothing but the report goes to standard output, and errors go to standard error.

Plain lines look like this:

$ speedtest-go --unix

    speedtest-go v1.8.0 (1559e47, 2026-05-02)

✓ ISP: 203.0.113.7 (Fujitsu) [34.9769, 138.3831]
✓ Found 20 Public Servers

✓ Test Server: [6691] 9.03km Shizuoka (Japan) by sudosan
✓ Latency: 4.452963ms Jitter: 41.271µs Min: 4.395179ms Max: 4.517576ms
✓ Packet Loss Analyzer: Running in background (<= 30 Secs)
✓ Download: 115.52 Mbps (Used: 135.75MB) (Latency: 4ms Jitter: 0ms Min: 4ms Max: 4ms)
✓ Upload: 4.02 Mbps (Used: 6.85MB) (Latency: 4ms Jitter: 1ms Min: 3ms Max: 8ms)
✓ Packet Loss: 8.82% (Sent: 217/Dup: 0/Max: 237)

Rate units

Rates are shown in Mbps by default. --unit chooses auto-scaled units instead:

Unit	Shows
`decimal-bits`	bps, Kbps, Mbps, Gbps
`decimal-bytes`	B/s, KB/s, MB/s, GB/s
`binary-bits`	Kibps, Mibps, Gibps
`binary-bytes`	KiB/s, MiB/s, GiB/s

speedtest-go --unit binary-bits

Hide your address

--mask-isp replaces the letters and digits of your IP address, ISP name, and coordinates with *, so 203.0.113.7 becomes ***.*.***.*.

Output	What is hidden
The `ISP:` line and `--unix` output	Your address, ISP name, and coordinates
`--json` and `--jsonl` reports	Your address, ISP name, and coordinates
The `Test Server:` line and `list`	Distances to servers
`--json` and `--jsonl` reports	Distances to servers, which are left out

Distances are hidden too, since distances to servers at known coordinates would reveal where you are. Your country is still shown.

speedtest-go --mask-isp --json
speedtest-go list --mask-isp

Test protocols