wscli

A lightweight and powerful Go command-line tool for interacting with WebSocket servers. Designed for testing, debugging, and scripting, wscli provides functionality similar to wscat but with additional features. Supports quick load testing.

🚀 Installation

Using Docker

$ docker run -it akshaykhairmode/wscli:latest -c "ws://example.com/ws"

Using go install

go install github.com/akshaykhairmode/wscli@latest

Using homebrew

brew tap akshaykhairmode/tools
brew install akshaykhairmode/tools/wscli

Download Prebuilt Binaries

If you don’t have Go installed, download the latest binaries from the Releases Page.

🔧 Usage

Connect to a WebSocket server

$ wscli -c ws://localhost:8080/ws

Connect with custom headers

$ wscli -c ws://localhost:8080/ws -H "Authorization: Bearer mytoken" -H "X-Custom: value"

Send a command immediately after connecting

$ wscli -c ws://localhost:8080/ws -x '{"action": "subscribe", "channel": "updates"}'

Send a close message with code 1000 and reason "normal closure"

$ wscli --slash -c ws://localhost:8080/ws
/close 1000 normal closure

Send a binary file

$ wscli --slash -c ws://localhost:8080/ws
/bfile /home/user/test.bin

✨ Features

• 🔹 Native Binaries: Easy installation across systems.
• 📤 Piped Input: Send piped input using | (disables interactive terminal features).
• 📨 Multiple Messages on Connect: Send multiple messages immediately after connecting.
• 🎭 Background Execution:
  • Run wscli in the background using nohup:

    $ nohup wscli -c ws://localhost/ws -w 1s > nohup.out 2>&1 &

  • Redirect output and run in the background:

    $ wscli -c ws://localhost/ws >> output.txt & 2>&1

• 📜 History Persistence: Maintain a command history for quick reuse.
• ⚡ Command Execution on Connect: Use -x to execute commands automatically.
• 📌 JSON Pretty Printing: Format JSON responses using --jspp.
• ⌨️ Terminal Shortcuts: Supports readline shortcuts like Ctrl+W (delete word) and Ctrl+R (reverse search). See full list.
• 🗂️ Binary File Transfer: Send a file as a binary message.
• 📊 Load Testing: Perform load tests using the --perf flag.

🛠 Available Flags

Flag	Shorthand	Description
--auth		HTTP Basic Authentication (username:password).
--binary	-b	Send hex-encoded data.
--ca		Path to the CA certificate file (optional).
--cert		Path to the client certificate file (optional).
--connect	-c	WebSocket connection URL.
--execute	-x	Execute a command after connecting.
--gzipr		Enable gzip decoding (server must send messages as binary).
--header	-H	Custom headers (key:value).
--help	-h	Show help information.
--jspp		Enable JSON pretty printing.
--key		Path to the certificate key file (optional).
--no-check	-n	Disable TLS certificate verification.
--no-color		Disable colored output.
--origin	-o	Specify origin for the WebSocket connection.
--proxy		Use a proxy URL.
--response	-r	Show HTTP response headers.
--show-ping-pong	-P	Show ping/pong messages.
--slash		Enable slash commands.
--sub-protocol	-s	Specify a WebSocket sub-protocol.
--verbose	-v	Enable debug logging.
--version	-V	Show version information.
--wait	-w	Wait time after execution (1s, 1m, 1h).
--print-interval		The interval for printing the output. Default is 1s.
--ping-interval		The interval for pinging to the connected server. Default is 30s.
--perf		Enable performance testing.
--std-out		print the received messages in standard output, default is standard error.

🛠 Slash Commands (Enable via --slash)

Command	Description
/flags	Show loaded flags.
/ping	Send a ping message.
/pong	Send a pong message.
/close	Send a close message (/close <code> <reason>).
/bfile	Send a file (/bfile <file_path>). Max size: 50MB.

📊 Load Testing (Enable via --perf)

Flag	Description	Data Type
--tc	Total number of connections.	unsigned integer
--lm	Load message to send. Can use templates defined below. File input supported.	string
--am	Authentication message. Can use templates defined below. File input supported.	string
--mi	Message interval. (default: 0s). If not set, then lm will be sent only once.	duration
--waa	Wait time after authentication before sending load messages.	duration
--wba	Wait time before sending auth message to the server	duration
--rups	Connections ramp-up per second (default: 1).	unsigned integer
--outfile	Do not open the tview output and write the output to file.	string
--pconfig	Take perf config from file. Pass the file path here. The format of the file is available here. This will override all other perf flags even if set.	string

Note: --lm and --am also support file input. Provide an absolute path to send messages from a file. The file reading will restart from the first line when EOF is reached. If file is less than 10MB then we store it in memory. "\n" is the delimeter.

Load Message Templates

Function	Description	Parameters	Data Types
RandomNum	Generates a random number between 0 and <max> (default range: 0–10,000).	<max> (optional)	Integer
RandomUUID	Generates a random UUID.	None	N/A
RandomAN	Generates a random alphanumeric string with the specified <length> (default: 10 characters).	<length> (optional)	Integer
UniqSeq	Generates a unique atomic sequence within a specified <group>. Multiple connections share the same sequence when using the same group. The <start> value sets the initial number (default: 0). If different start values are provided, the first one is used. Examples: - {{UniqSeq "1" 10}} != {{UniqSeq "1" 10}} (Not the same number) - {{UniqSeq "0"}} == {{UniqSeq "1"}} (Different groups generate the same number)	<group> <start> (optional)	String Integer
.Seq	Generates a sequence starting from 0 for each connection. No shared counters.

Example

$ wscli -c ws://localhost:8080/ws --perf --tc 1000 --lm "hello world {{RandomNum 50}}" --rups 100 --mi 1s

OR

$ wscli -c ws://localhost:8080/ws --perf --tc 1000 --lm "/tmp/load.txt" --rups 100 --mi 1s

# Flags used:
# --perf (enable performance testing)
# --tc 1000 (create 1000 connections)
# --lm "hello world {{RandomNumber 50}}" (load message, generate a random number from 0 to 50)
# --lm "/tmp/load.txt" (load message, read from file)
# --rups 100 (ramp up 100 connections per second)
# --mi 1s (send 1 message per second)

Normal Output

Perf output:

Perf Verbose output:

Demo