stressor is a tool, that runs a sequence of activities in one or more parallel sessions.
The most common use case is to run a test script with HTTP commands against a web server, simulating a bunch of parallel user sessions.
As a result we get metrics about reponse times, failures, resource usage, etc.

Stressor can be used for testing, benchmarking, load testing, or to generate test data.
Stressor comes with prebuilt activities for HTTP-request and more, and can be extended by custom activity-plugins.

Test scripts can be defined as text files, using a special syntax, that is then executed by the stressor command line tool.
Stressor is also an Open Source Python library that can be included into your own projects. This allows to define test scenarios programmtically.


A run configuration describes all aspects of a test suite. It defines one scenario and additional options.

A scenario defines a list of sequences that are executed in order, possibly looping. Think of it as a kind of story book that describes one user’s behavior.
During a run, the scenario is executed in one or more parallel user sessions.

Sequences are lists of activities that are executed in order. Sequences named ‘init’ and ‘end’ are typically reserved to set-up and tear-down scenarios. Often we have a looping ‘main’ sequence in the middle, but we can define more sequences with arbitrary names.

Activities are the smallest building blocks of scenarios. Typical activies are GetRequest, PutRequest, RunScript, Sleep, …
Every activity can be configured, for example with a request URL and parameters, checks for expected results, etc.
Custom plugins can be developed and installed to make additional activities available.

While the scenario is executed, a dictionary of global variables is available. Activities can access this context in order to read configuration or pass information along.

Macros are used in activity definitions to pass context variables as options.

When a scenario is run, one or more sessions are executed in parallel. Every session has a virtual user assigned.

The command line interface (CLI) can be run from the computer console. It will read and compile the configuration file, execute the scenario, and display results and statistics.
Alternativly include the Python `stressor` package in your project, define, configure, and run the scenario programmatically.

The CLI can open a monitor application that displays the current execution statistics in real time.