Command line	Environment	Config file	Description
-f, --locustfile	LOCUST_LOCUSTFILE	locustfile	The Python file or module that contains your test, e.g. ‘my_test.py’. Accepts multiple comma-separated .py files, a package name/directory or a url to a remote locustfile. Defaults to ‘locustfile.py’.
-H, --host	LOCUST_HOST	host	Host to load test, in the following format: https://www.example.com
-u, --users	LOCUST_USERS	users	Peak number of concurrent Locust users. Primarily used together with –headless or –autostart. Can be changed during a test by keyboard inputs w, W (spawn 1, 10 users) and s, S (stop 1, 10 users)
-r, --spawn-rate	LOCUST_SPAWN_RATE	spawn-rate	Rate to spawn users at (users per second). Primarily used together with –headless or –autostart
-t, --run-time	LOCUST_RUN_TIME	run-time	Stop after the specified amount of time, e.g. (300s, 20m, 3h, 1h30m, etc.). Only used together with –headless or –autostart. Defaults to run forever.
--config-users	LOCUST_CONFIG_USERS	config-users	User configuration as a JSON string or file. A list of arguments or an Array of JSON configuration may be provided
--web-host	LOCUST_WEB_HOST	web-host	Host to bind the web interface to. Defaults to ‘*’ (all interfaces)
--web-port, -P	LOCUST_WEB_PORT	web-port	Port on which to run web host
--headless	LOCUST_HEADLESS	headless	Disable the web interface, and start the test immediately. Use -u and -t to control user count and run time
--autostart	LOCUST_AUTOSTART	autostart	Starts the test immediately (like –headless, but without disabling the web UI)
--autoquit	LOCUST_AUTOQUIT	autoquit	Quits Locust entirely, X seconds after the run is finished. Only used together with –autostart. The default is to keep Locust running until you shut it down using CTRL+C
--web-login	LOCUST_WEB_LOGIN	web-login	Protects the web interface with a login page. See https://docs.locust.io/en/stable/extending-locust.html#authentication
--tls-cert	LOCUST_TLS_CERT	tls-cert	Optional path to TLS certificate to use to serve over HTTPS
--tls-key	LOCUST_TLS_KEY	tls-key	Optional path to TLS private key to use to serve over HTTPS
--class-picker	LOCUST_USERCLASS_PICKER	class-picker	Enable select boxes in the web interface to choose from all available User classes and Shape classes
--master	LOCUST_MODE_MASTER	master	Launch locust as a master node, to which worker nodes connect.
--master-bind-host	LOCUST_MASTER_BIND_HOST	master-bind-host	IP address for the master to listen on, e.g ‘192.168.1.1’. Defaults to * (all available interfaces).
--master-bind-port	LOCUST_MASTER_BIND_PORT	master-bind-port	Port for the master to listen on. Defaults to 5557.
--expect-workers	LOCUST_EXPECT_WORKERS	expect-workers	Delay starting the test until this number of workers have connected (only used in combination with –headless/–autostart).
--expect-workers-max-wait	LOCUST_EXPECT_WORKERS_MAX_WAIT	expect-workers-max-wait	How long should the master wait for workers to connect before giving up. Defaults to wait forever
--worker	LOCUST_MODE_WORKER	worker	Set locust to run in distributed mode with this process as worker. Can be combined with setting –locustfile to ‘-’ to download it from master.
--processes	LOCUST_PROCESSES	processes	Number of times to fork the locust process, to enable using system. Combine with –worker flag or let it automatically set –worker and –master flags for an all-in-one-solution. Not available on Windows. Experimental.
--master-host	LOCUST_MASTER_NODE_HOST	master-host	Hostname of locust master node to connect to. Defaults to 127.0.0.1.
--master-port	LOCUST_MASTER_NODE_PORT	master-port	Port to connect to on master node. Defaults to 5557.
--web-base-path	LOCUST_WEB_BASE_PATH	web-base-path	Base path for the web interface (e.g., ‘/locust’). Default is empty (root path).
-T, --tags	LOCUST_TAGS	tags	List of tags to include in the test, so only tasks with at least one matching tag will be executed
-E, --exclude-tags	LOCUST_EXCLUDE_TAGS	exclude-tags	List of tags to exclude from the test, so only tasks with no matching tags will be executed
--csv	LOCUST_CSV	csv	Store request stats to files in CSV format. Setting this option will generate three files: <filename>_stats.csv, <filename>_stats_history.csv and <filename>_failures.csv. Any folders part of the prefix will be automatically created
--csv-full-history	LOCUST_CSV_FULL_HISTORY	csv-full-history	Store each stats entry in CSV format to _stats_history.csv file. You must also specify the ‘–csv’ argument to enable this.
--print-stats	LOCUST_PRINT_STATS	print-stats	Enable periodic printing of request stats in UI runs
--only-summary	LOCUST_ONLY_SUMMARY	only-summary	Disable periodic printing of request stats during –headless run
--reset-stats	LOCUST_RESET_STATS	reset-stats	Reset statistics once spawning has been completed. Should be set on both master and workers when running in distributed mode
--html	LOCUST_HTML	html	Store HTML report to file path specified. Able to parse certain tags - {u}, {r}, {t} and convert them to number of users, spawn rate and run time respectively.
--skip-log-setup	LOCUST_SKIP_LOG_SETUP	skip-log-setup	Disable Locust’s logging setup. Instead, the configuration is provided by the Locust test or Python defaults.
--loglevel, -L	LOCUST_LOGLEVEL	loglevel	Choose between DEBUG/INFO/WARNING/ERROR/CRITICAL. Default is INFO.
--logfile	LOCUST_LOGFILE	logfile	Path to log file. If not set, log will go to stderr
--exit-code-on-error	LOCUST_EXIT_CODE_ON_ERROR	exit-code-on-error	Sets the process exit code to use when a test result contain any failure or error. Defaults to 1.
-s, --stop-timeout	LOCUST_STOP_TIMEOUT	stop-timeout	Number of seconds to wait for a simulated user to complete any executing task before exiting. Default is to terminate immediately. When running distributed, this only needs to be specified on the master.
--otel	LOCUST_ENABLE_OPENTELEMETRY	otel	Instrument the Locust test run with OpenTelemetry.