Loadster is a cloud-based load testing and synthetic monitoring platform for engineers who want to know how their applications behave under real traffic.

Tests run with three types of bots: Protocol Bots for HTTP testing, headless Browser Bots that render full pages and execute JavaScript in real Chrome browsers, and Playwright bots for when you want to use Playwright JS directly.

Loadster scripts can be recorded from Chrome or Firefox with the Loadster Recorder extension, edited in a built-in editor with variables, datasets, and shared includes, and then replayed from multiple cloud regions.

Each test run returns detailed page timings (TTFB, FCP, LCP, CLS, etc) alongside resource waterfalls, screenshots, and full traces you can step through in a self-hosted trace viewer. Tests scale from a handful of virtual users (bots) to hundreds of thousands across distributed cloud engines without you provisioning anything.

The same scripts can be set up as monitors that run on a schedule from chosen regions. Notification policies route incidents to email, SMS, voice, or integrations like Slack and PagerDuty. Projects, roles, and shared test history keep teams aligned on what passed, what failed, and what changed.

Pricing is usage-based via Loadster Fuel, with 50 free units on sign-up and no credit card to start.

Core HttpMaster features are: * HttpMaster project to store complete definition of API calls in one single place. * Broad set of http properties. * Dynamic parameters to simulate variations of input data or create global API values. * Response data validation with logical expressions. * Request chaining to use data from previous request with the next request. * Extensive data upload support, including 'multipart/form-data'. * Request data builder for creating request body with an optional dynamic parameters. * Request item execution with detailed progress monitoring. * Execution groups to create batches of requests. * Comprehensive execution data review and management. * Additional tools (basic request tool for ad-hoc execution, command line interface, OpenAPI import, etc).