Measurements

Finding servers

Call	Returns
`client.FetchUserInfo(ctx)`	Your IP address, ISP, coordinates, and country, as speedtest.net reports them
`client.FetchServers(ctx)`	The servers near you, or near the location option
`client.FetchServerByID(ctx, id)`	One server by its ID, or `ErrServerNotFound`
`client.CustomServer(url)`	A server that speedtest.net does not need to list, from its full URL, such as `http://speedtest.example.com:8080`. Its path is replaced with `/speedtest/upload.php`
`servers.FindServer(ids)`	The servers with those IDs. With no IDs, or none that match, the server with the lowest latency
`servers.FilterCountry(codes...)`	The servers in those countries, by two-letter code
`servers.Available()`	The servers with a measured latency

Tests

Each test takes a context and a server, and returns its own result. Ending the context ends the test early, which makes it fail.

Method	Measures	Returns
`Ping(ctx, server, opts...)`	Latency, with the client’s ping mode	`PingStats`
`Download(ctx, server, opts...)`	The download rate	`Transfer`
`Upload(ctx, server, opts...)`	The upload rate	`Transfer`
`DownloadMulti(ctx, main, pool, opts...)`	The download rate across several servers at once. The main server gets the main share of the connections, and the other available servers in the pool share the rest	`Transfer`
`UploadMulti(ctx, main, pool, opts...)`	The upload rate across several servers, shared like `DownloadMulti`	`Transfer`
`PacketLoss(ctx, server)`	Packet loss, until the context ends. See Packet Loss	`PacketLossStats`

Options for one test

Option	For	Sets	Default
`WithPingCount(n)`	`Ping`	The number of round trips	10
`WithPingInterval(d)`	`Ping`	The wait after each round trip	200 milliseconds
`WithLatencyCallback(fn)`	`Ping`	A function that receives each round trip as it is measured	None
`WithProgressCallback(fn)`	Transfers	A function that receives the rate estimate, the elapsed time, and the estimated time left while the test runs	None

Results

PingStats:

Field	Holds
`Latency`	The mean round trip
`Jitter`	The standard deviation of the round trips
`Min`, `Max`	The shortest and longest round trips
`Latencies`	Every round trip, in the order they were sent
`Duration`	How long the measurement took

Transfer:

Field	Holds
`Rate`	Bytes per second over the test’s capture window, or -1 when no data was counted and more than a tenth of the requests failed
`Bytes`	The bytes downloaded, or the upload bytes the servers confirmed
`Sent`	The upload bytes sent, confirmed or not. 0 for downloads
`Window`	The capture window the rate is measured over
`Duration`	How long the test took
`Requests`, `Failures`	How many requests the test sent, and how many failed
`Connections`	The bytes, requests, failures, and active time of each connection

A ByteRate such as Transfer.Rate prints in Mbps. Format chooses another unit, such as rate.Format(speedtest.UnitTypeBinaryBits), and Mbps and Gbps return numbers.

JSON

A speedtest.Result collects one server’s results. speedtest.JSON and speedtest.JSONL write results in the CLI’s JSON format, described in Reading the Results:

report, err := speedtest.JSON(user, []speedtest.Result{{
	Server:   server,
	Ping:     &ping,
	Download: &download,
	Upload:   &upload,
}})

Errors

Check errors with errors.Is and errors.As:

Error	Means
`ErrInvalidOption`	`New` rejected a client option, or `Ping` rejected a ping option
`ErrServerNotFound`	No server is available, or none has the requested ID
`*StatusError`, wrapping `ErrUnexpectedStatus`	A server answered with an HTTP status outside 2xx
`ErrUnsupported`	A server does not serve the packet loss protocol
`context.Canceled`, `context.DeadlineExceeded`	The test’s context ended before it finished

Client Options Packet Loss