Custom Monitor
Custom monitors run reusable scenarios on shared Testable-hosted or self-hosted runners, or on per-check cloud VMs when that feature is enabled. Use them when a simple HTTP, ping, port, or heartbeat check is not enough to prove that a user flow or business process works.
Supported Scenario Types
| Type | Use it for |
|---|---|
| Playwright | Modern browser journeys and end-to-end checks. |
| Puppeteer | Chrome-based browser automation and generated URL checks. |
| Load in Chrome | Create a generated Puppeteer scenario that loads a target URL. |
| Selenium | Cross-browser or existing Selenium workflows. |
| Node.js Script | Custom JavaScript checks and API workflows. |
| JMeter | HTTP test plans and performance-oriented checks. |
| Gatling | Scala-based simulations and API workflows. |
| Locust | Python-based user flows and service checks. |
| PhantomJS | Legacy browser scripts. |
| HAR Replay | Replay captured HTTP traffic. |
| Postman | API collections and environment-driven checks. |
| Java | Custom Java checks. |
| Monitor | Reusable protocol-level HTTP, ping, port, and related endpoint scenarios. |
| AI | AI-authored monitoring scenarios when enabled for the organization. |
Configuration
Scenario Selection
Choose an existing scenario or create a new one from the monitor form. New scenarios are created in the selected folder and group, then edited inline with the embedded scenario editor.
Scenario Parameters
Scenarios can declare parameters so the same scenario definition can power multiple monitors. Required parameters are shown on the monitor form and saved with the monitor.
Scheduling, Regions, and Success Criteria
Custom monitors use the same schedule, region, notification, maintenance window, metrics, and success criteria panels as other runner-based monitors. A region can use a shared pool or a per-check runner. Success criteria can be configured globally, by monitor type, and by custom scenario type in organization monitor settings.
Results
Custom monitor incidents show the execution that caused the incident and, when available, the execution that resolved it. This makes it possible to inspect steps, timings, assertions, logs, screenshots, and other scenario artifacts from the incident page.
Use Cases
- Login, checkout, signup, or other browser user journeys.
- Multi-step API flows that require authentication or state.
- Business validations that combine UI, API, and custom assertions.
- Private workflows that need self-hosted runners inside your network.
- Reuse of existing Postman, JMeter, Gatling, Locust, Selenium, Playwright, or Puppeteer assets.
Best Practices
- Keep scenarios focused on one user-visible behavior.
- Use parameters for environment, usernames, paths, IDs, or other per-monitor differences.
- Prefer stable selectors and explicit assertions for browser checks.
- Choose runner regions close to the users or infrastructure you are validating.
- Use success criteria to alert on degraded performance before a scenario fails completely.